Wikipedia talk:WikiProject Mathematics/Archive2005

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Jan 2005 – Mar 2005

Graph (mathematics) vs Graph theory

I am currently working on graph (mathematics) and graph theory. It is not clear to me what sort of distinction to draw between those two articles. User:Oleg Alexandrov has similar problems on matrix (mathematics) and matrix theory. Other articles having the same problem are

My opinion is the basic article (e.g graph) should contain

  • brief motivation
  • definitions
  • examples
  • generalizations of definition

whereas the theory article should contain

  • history
  • detailed motivation
  • relation to other areas
  • important problems

Any comments ? MathMartin 12:35, 7 Jan 2005 (UTC)

I don't think there should be two pages at all. One of them should be a redirect to the other and all the material should be on the same page unless some subtopic (maybe "History of X theory") grows large enough to be its own article. --Zero 13:18, 7 Jan 2005 (UTC)

I think for all of these topics, there should be the two pages mentioned (and more, each should eventually have a "history of" article also, giving a detailed and comprehensive history), and I think that MathMartin's description of how they should differ seems reasonable to me. See also Set theory, Set, Naive set theory and Axiomatic set theory. Paul August 14:19, Jan 7, 2005 (UTC)

I think Zero has a point. Ideally, one article should be enough. However, the longer articles get, the harder is to keep a "global picture" of the article. This has many consequences, among them being that mistakes are easier to slip through, consitency is harder to keep, etc. This is especially true on such an anarchic place like Wikipedia, where ultimately nobody is in charge of anything. So I would suggest splitting articles, which clear motivation, like MathMartin suggests. To to a good job at that, is not so easy though. Oleg Alexandrov 19:18, 7 Jan 2005 (UTC)

Here is my current (changed) opinion on this topic. In general there should be only one article called X theory. If this article grows too large certain parts of the article should be put into separate articles (like history of X theory) so that we get a hierarchical structure of articles. The subarticles (like history of X theory) should have a name making it obvious what sort of content belongs to the article. The subarticles should have a link to the main article at the top.

I think this hierarchy of articles is preferable to my earlier suggestion of parallel articles because it provides a

  • clearer and more intuitive structure for the reader
  • allows for better editing as the article can grow gradually from one article to a tree of articles without the need for restructering several articles at once

Several articles like french language, france or category theory already use this structure. I will merge graph (mathematics) into graph theory to provide a concrete example. MathMartin 15:15, 9 Jan 2005 (UTC)

Please don't. There is a specific need for short articles that give a definition and some examples, versus longer articles that talk about the theory in general. -- Walt Pohl 08:19, 10 Jan 2005 (UTC)
I already merged them. Can you point to any discussion on this subject or give a more detailed explaination ? MathMartin 10:12, 10 Jan 2005 (UTC)
MathMartin: As I said above, I think it would be better if these articles were kept separate. I agree with Walt Pohl, that there is a need for a short article that, for example, defines "graph",and gives some examples, so that a user doesn't have to wade through a longer article for that information. I think your original idea was correct, and so did Oleg Alexandrov, who gave some excellent reasons for supporting your idea. I don't understand why you changed your mind? I think you should consider changing it again ;-) Paul August 22:10, Jan 10, 2005 (UTC)
I also agree. It's nice to be able to say "In graph theory, the 'Petersen graph is a graph that ...". The first link gives the broad theory, the second gives a particular definition. Dbenbenn 22:26, 10 Jan 2005 (UTC)
I've always assumed that was the rationale for the division between X and X theory, though I'm not sure I've ever seen it spelled out. The rationale, as I have perceived it, is: most of the time, an article that mentions X just needs the definition, and not the whole theory. For example, the integers form a ring; it's sufficient to be able to jump to the definition, rather than a topic on ring theory, which will talk about noncommutative rings, ideals, etc. It makes using convenient math terminology somewhat more intimidating to use.
It could be that the way you're suggesting really is better, but since it's something of a de facto standard on math pages, I think it's something we should hash out here. -- Walt Pohl 23:10, 10 Jan 2005 (UTC)
I think MathMartin's action was a little premature given the active discussion on the issue, but on the other hand I think the structure is better now than it was before. I have no problem with an article containing mostly definitions, but the problem with the 2-part structure is that the theory page either has to repeat the definitions or to leave them out. The first is clearly undesirable. The second is also undesirable since someone reading the theory page should not need to flick back and forth to another page in order to understand it. I think the structure MathMartin has established is actually pretty good; of course there is always room for tweaking. --Zero 00:22, 11 Jan 2005 (UTC)
There is no harm in repeating the definition — as long as they are the same! ;-) Paul August 02:51, Jan 11, 2005 (UTC)
Even if they start off the same, sooner or later they will diverge. It always happens that way. --Zero 06:43, 11 Jan 2005 (UTC)
Well they don't have to be identically worded, as long as they are mathematically equivalent. Different ways of presenting the same definition can be a good thing. Of course, a definition may be edited, so as to become incorrect. And, of course, this can happen, whether there is one version of the definition or not. However, such an error is less likely to occur, and is easier to fix, if there is another "repeated" definition to which to refer;-) Paul August 15:21, Jan 11, 2005 (UTC)
Please, keep them separate. From a purely mathematical point of view, graph theory is a different entity than graph, it is like set of all theorems about graphs. Also, graph theory evolved (among other things) from study of minimal weighted spanning trees - where the spanning tree was defined as a rigid body of rods connecting set of points in Euclidean space, and the weight was given by the length of rods (that's definition Jarnik and Boruvka used, I think). See Boruvka's algorithm,Prim's algorithm (now I am looking at it, and don't quite understand the difference among these algorithms - it seems that they only differ in clever use of data structures, but the greedy method is always used; they should be merged in one article probably). Anyway, such historical connections are inapropriate in article about graph. Samohyl Jan 16:48, 11 Jan 2005 (UTC)

I will try to separate the pages again while trying to keep the hierarchical structure. My main point is, if we have separate pages on topics which are very similar, the ordering/relationship between the pages should be sufficiently clear even to a novice reader/editor. MathMartin 17:01, 11 Jan 2005 (UTC)

There is no need, necessarily, to remove any current content from Graph theory. As long as what is there now is relevant to it, which presumably it is. All that needs to be done, really, is recreate the Graph (mathematics) article, more or less as it was before the merge. There can be considerable content overlap between the "theory" article and the "graph" article. In my view, the main difference between them should be functional. The "graph" article should be narrow and concise, just explaining what a graph is. The "graph theory" article should be broad and comprehensive, saying what a "graph" is, in detail, as well as what "graph theory" is, in as complete a way as possible.
The problem of article "structure" is an important one. Martin is right to be considering it. I am glad he has brought it up here for discussion, and I would like to thank him for doing so. (Martin: Thanks ;-) As he says, having separate but related articles, for which the relationships are unclear is problematic. For example there is a real danger (and this may have already happened, to some extent) of our "graph" article becoming, more and more, like an article about "graph theory", without its editors being aware of, or taking sufficient notice of, the fact that there was already an article on "graph theory". We need to be vigilant against this. Adding some italicized disambiguation text at the beginning of each article explaining what the article is about and the existence of the other article, might help, in this regard.
Figuring out the best way to organize our mathematical content is a difficult problem with no easy solution. It will behoove us to give lots of serious thought to this and devote more time discussing it. I will say though, that I don't think that the ideal structure for these articles in Wikipedia is a "hierarchical" top-down one. Wikipedia just isn't like that. Nor in reality are most of the topics it covers. Even in mathematics where one might in principle organize all of the subject in one great hierarchy — and mighty and heroic attempts have been made to do just that — this is not, in my opinion, the best way, really, to think about mathematics, nor to learn it, nor to present it in an encyclopedia. The "true" structure of mathematics, in my view, while involving many hierarchies, is much more complicated. And, as it happens, Wikipedia is well suited to reflect this ;-)
Paul August 19:10, Jan 11, 2005 (UTC)

I have separated the pages and fixed the links. I did not duplicate the definitions because I think duplicating basic definitions is confusing for the reader. I think graph theory is understandable even without a definition of what a graph really is, because of the informal discussion in the introduction. MathMartin 18:39, 11 Jan 2005 (UTC)

I'm new here, so I can give an outsider's view on the split structure -- it's terrible. Not least because graph leads to a disambiguation page which confusing in itself -- until you finally realise you want graph (mathematics)... and then that all the information is under graph theory. A hierarchical structure under graph theory would lead to much less confusion. It does not necessarily mean graph theory has to grow out of hand as it can lead to more subtopics. Also on subtopics, I'd like to start a discussion on better linking to graph theory applications (as I said, I'm new, I'll take a look round first). Particularly I notice that network analysis and social networks could be better brought together. --stochata 20:33, 30 Jan 2005 (UTC)
I just flagged all three articles (Graph theory, Graph (mathematics), Glossary of graph theory) for a merge, ignorant of this discussion. I do agree that more than one page is a Good Idea, but I don't think the way the material is now sorted out is any good at all. I'm a fairly smart guy, with plenty of background. (Not to put on airs, but my mother was a prominent graph theorist and I grew up with the material the way other kids grew up with Curious George.) And still, when I read the "introductory" material at Graph (mathematics), I about drowned -- I am a little out of practice.
I just finished reworking and expanding Seven Bridges of Königsberg; this was one of my bedtime stories and I know it by heart, but I wanted to be sure to use all the correct terms. I ended up researching the jargon on the net external to WP and building my own glossary, which I slipped into Graph theory -- the only place I expected to see any general article on the subject. I'm not sorry I did, either; I sure didn't duplicate the advanced article at Glossary of graph theory, which reads more like a syllabus or perhaps a sheaf of classnotes.
I am going to go way out on a limb here and say I may be the most qualified individual to work over this stuff. Most folks know nothing at all about the subject and could care less. Experts know the material so well that they have difficulty explaining it to the unwashed horde. This is not the place for a textbook. Yes, there's no harm in presenting some advanced material (what experts consider to be the absolute minimum basics) for the few who are willing to work through it. But the bulk of people who visit just need to get a quick handle on the topic. I am a long way from being an expert on graph theory, but I believe I at least know enough to know when I don't know what I'm doing, and I won't monkey with anything like that without discussing it. I would like an expert to work with me on this, to check my work as I go along, to make suggestions.
If you want to see how I go about things, then besides looking at the seven bridges, you can check out my one-day glossary at Graph theory#Glossary. I think that is the kind of introductory material that needs to be most accessible to the casual reader. I shouldn't throw out the advanced stuff, but it should be clearly so labeled and better organized.
I see that this area has already been the subject of one hasty restructuring. I plan to replicate the existing material on a few dummy pages and edit them there. When this group reaches some sort of concensus on the dummies, we can change the "real" pages to follow.
Again, if it's not clear, I'm here recruiting an expert buddy for this effort. — Xiong (talk) 02:41, 2005 Mar 21 (UTC)

I have also been struggling with these unstructuredly interrelated pages. I have to say that I think what happened to the set theories is extremely horrible in ways of structure and duplication and ease of finding what you're looking for. Also in this way it is extremely hard to add information, since it is quite unclear what the best place for it is. Thus I would also ague for a hierarchic approach. The fact that mathematics may not be hierarchical itself doesn't present a problem, because of all the wikilinks. Graph theory may be an ideal area to work on, since there are so many excellent examples (wikipedia itself!) and could thus have a great motivational sections. As an aside I really dislike the glossaries. Perhaps we should incorporate them into the main storyline. And while we're at it add some lemma's, which are the reason d'etre for all those defs after all. -MarSch 13:37, 7 Apr 2005 (UTC)

joy of tex

I am trying to put a few equations in Hull-White model, but, at least on my browser the equations seem to come out in different sizes. Any tips on how to make the page look a little neater? Thanks. Pcb21| Pete 23:03, 13 Jan 2005 (UTC)

The size problem is because some of the equations are images generated by Wikipedia, which doesn't know the browser's font size. You could fix the problem by forcing all the displayed equations to be images, but I think that solution would be worse than the problem. Dbenbenn 23:33, 13 Jan 2005 (UTC)
Not necessarily - at least the page looks consistent. I've done so. Try to also avoid inline <math> (use HTML), since that usually comes out as a PNG inline and doesn't look very nice. Dysprosia 23:51, 13 Jan 2005 (UTC)

Bug in new version

Has anyone noticed that putting math tags inside a link (like this: [[Lp space|<math>L^p</math> space]]) no longer works? (See Sobolev space for an example). When did that happen? Should we file a bug report? Where do you file bug reports so that they are actually noticed? Uffish 02:56, 14 Jan 2005 (UTC)


A little note on using purple dotted boxes

Don't. JRM 19:02, 2005 Jan 16 (UTC)

Or less facetiously: at least use "class='theorem'" or similar in addition to the style comment. This will allow updated style sheets to render theorems in whatever fashion the user wants, and to override any style you put in.

Wikipedia:WikiProject Mathematics has this article lost focus?

Greetings from a fellow mathematician. I am happy there are so many of us hanging around on Wikipedia. And I like the Wikipedia:WikiProject Mathematics thing. However, it seems to me there is just too much stuff in there, which could be better organized.

For instance, the second half of it could be condensed in a usage and style manual for writing Wikipedia articles on Mathematics, and put on a separate page. It could also be merged with Wikipedia:Styles of Mathematics Articles which seems to have never got off the ground.

The list of participants is getting large. Maybe it could go in a separate article too.

Also, some of the stuff in the article could be safely moved to the talk page, after incorporating all the insights written there in the usage and style manual above.

These are just some thoughts. It just looks to me this page lost some focus. What do you think?

Oleg Alexandrov 05:15, 18 Jan 2005 (UTC)

Yes, we could use some subpages now. Charles Matthews 13:58, 18 Jan 2005 (UTC)
I wasn't ever aware of it having any focus. If the question is whether it lacks focus, I will agree. But it has never been clear to me what this page is for. -- Dominus 14:21, 18 Jan 2005 (UTC)
I agree with Dominus that this page never really had focus. We've just used it as a place to thrash out issues on math pages. -- Walt Pohl 20:18, 18 Jan 2005 (UTC)
I agree with all of the above. Oleg: If you want to try to improve the focus and organization of the page in some of the ways (or others) you mention, I think that would be fine with me. You could just go ahead and give it a go ;-) ( See: Wikipedia:Be bold). But be prepared for possible objections to any changes you make ;-) Or you could try to discuss changes here first, especially if they are significant. Paul August 20:59, Jan 18, 2005 (UTC)

To be specific, I want to make some of this stuff into a true usage guide for math articles, that is a Wikipedia: Manual of style for math articles. How's that? Oleg Alexandrov 21:31, 18 Jan 2005 (UTC)

And I do mean on a separate page.... Oleg Alexandrov 21:42, 18 Jan 2005 (UTC)

Wikipedia:How to write a Wikipedia article on Mathematics

Well, having heard several why`s, one be bold, and no no`s, I forked out an article with the title above. Such an article is obviously necessary, and while what is here at WikiProject Mathematics has good stuff, it looks too much like a talk page. This new article still needs lots of work. For now I did not do much, as I don't want to wake up tomorrow morning seeing in my watchlist things like "reverted", "redirected", or even "submitted for speedy deletion". :)

If nobody objects (if you do, say it now :), then in several days I will continue polishing the new thing. Of course, if you contribute things to it, or if you simply add it to your watchlist, it will help.

Oleg Alexandrov 02:55, 20 Jan 2005 (UTC)

Thanks Oleg. I have reorganised and updated the project page; now there is much common material, and you may want to cut out from the project page most of the issues covered in your 'manual'. Charles Matthews 10:19, 20 Jan 2005 (UTC)

\pi image in Template:Math-stub

There is some debate over the use of a \pi image in Template:Math-stub; there's small edit war going on. Please see Template talk:Math-stub#Pi_image if you care to voice an opinion. (Please do not discuss this here; discuss it there; thanks.)msh210 04:47, 27 Jan 2005 (UTC)


I've been talking with the guy that runs (we go back 6 years). I'm in the preliminary stages of setting up a project to move over the content from PM to WP. Uncreated articles can pretty much be copied directly over, but others can be merged in or if the WP article is better then nothing needs to be done. PM's under the GFDL. The major difference between WP and PM is that PM allows users to own articles. Anyway, I'm wondering what you all think of this, and whether it could be a subproject of this project or if it should go somewhere else. I haven't been able to find precedent on this sort of thing. If anyone wants more details/has questions, please let me know! CryptoDerk 05:06, Jan 27, 2005 (UTC)

Hi everybody, I run PlanetMath. I'm here to help out with this process as best I can. I also would like to go the other direction, porting some Wikipedia content to PM, but that is of course mostly my problem. I just need to figure out how to best get the math subset of articles from here. Though, I do have the same history preservation problem you've been discussing for the PM->WP port, so I am especially interested in that discussion. Please know that you have me as a resource to provide advice and possibly system enhancements that would make the porting job easier. --Aaron Krowne 05:40, 28 Jan 2005 (UTC)

That is a great idea. Just yesterday I copied the very nice Potential theory article from there, as here there was nothing. Their articles are more formal than what we have in here. So when copied over those articles (a) need some more introduction and motivation, (b) some sentences need to formulated to use less symbols and some formulas HTML-ized (e.g., make into x in C) (c) Links to other Wikipedia subjects need to be made, and this can be time-consuming. But doing all these is well-worth it.

Those people use an idea which I find extremely nice. Each article has an official maintainer who actually has a big picture of the article, and screens all the incoming changes.

Oleg Alexandrov | talk 05:37, 27 Jan 2005 (UTC)

Yes, formality is one reason why he doesn't just want to merge the two together -- he intends to keep running PM primarily for researchers and research-related interests. So... should an organizational page for this be a subpage of this WikiProject in mathematics, or should it go somewhere else? CryptoDerk 05:48, Jan 27, 2005 (UTC)
While that is the way the site has developed, we would actually like more introductory and, shall we say, more "pedagogically complete" articles. I think in terms of coverage it is probably more natural for PM to subsume Wikipedia's math section. However this is all academic... for now we should each just focus on how to copy over whatever portions of the other's content we want. --Aaron Krowne 05:40, 28 Jan 2005 (UTC)

There is of course room on Wikipedia for such a page. The big question is, what should be there and what is a good way of going about it. Oleg Alexandrov | talk 02:35, 28 Jan 2005 (UTC)

I can easily generate lists of pages of articles on PM as well as relevant redirects (PM entries a list of synonymous names at the end of the articles). The most important thing is coming up with a protocol for converting them (differences in style, including LaTeX, etc.) -- I'll come up with a draft page in my user space and post a link here within the next day or so. I think the most important decision that needs to be made is how to refer back to PM. It's my understanding that we need to provide a link to the history on PM, but do we do it like the EB 1911 notice "This article based in part on information from Encylopedia Britannica 1911" or do we put it in an "External link" section? CryptoDerk 03:12, Jan 28, 2005 (UTC)
I don't know that wholesale copying of PM articles to WP is appropriate, given the significant differences in purpose, organisation, presentation and form of PM -- but then I'm not sure that this is what you are proposing. The problem lies not only in identifying articles that don't yet exist on WP, but also in making sure that the topic isn't covered elsewhere (as is very common on WP). In a lot of cases, inclusion of a theorem or concept in a wider article is preferable in the context of WP, while it might reasonably be expected to have it's own entry on PM.
On other notes...
  • References back to PM might best be done (when content has been copied) using a new template for that purpose, if this becomes a common thing. That would make is trivial to append such a notice to the end of the relevant articles. Text to link back to the appropriate canonical name of the PM article can be included as an input into the template (IIRC).
  • A subproject of this one would probably be appropriate, I think. An excellent start (and this would go some way to addressing my reservations above) would be to compile a list of PM articles that don't appear to have WP equivalents, so that people can go there, take up the cause of a particular topic and work out what needs to be done with it. That would be a great place to track the status of such articles, too, as they will often need significant editing. This may be exactly what you are imaginging, in which case I'm all for it.
All in all: great idea, good luck with it, and I look forward to hearing more! Oh, and my kingdom for PM's TeX to HTML system, but I guess it wouldn't quite work on WP.
Ben Cairns 04:12, 28 Jan 2005 (UTC)
I agree with you that this shouldn't be a wholesale copying over of articles. In the draft page I'll be sure to set up some guidelines (that will undoubtedly be changed), but I'd say the majority of the encylopedia entries are probably useful. Some will need to be combined in some cases (they frequently have separate articles for proofs, for example).
A template is indeed what I had in mind, and yes it's possible to include a variable to link back to the appropriate PM article, even if it's named differently over here.
I imagine when all this is set up with just a raw listing of articles, some people can work on creating articles over here while others can work on categorization, perhaps with the following categories:
  • Article already exists on WP and PM content is already similar or less than what WP has, so no need to copy.
  • Article already exists on WP but PM content is different or better (stubs).
  • Article doesn't exist and should be converted.
  • Article has already been converted.
  • Unknown status, or unchecked (no category).
Once again, this is still preliminary, so don't yell at me if I'm leaving something obvious out :) CryptoDerk 04:34, Jan 28, 2005 (UTC)

Is there a list of PM article titles? One way to do all this would be to create a page like the mathematics Requested Articles page, but dedicated to PM articles. Since different articles will need to be treated different ways, we could see how much is accomplished by redirecting and sorting on such a page, and compiling a list of non-transfers, with reasons. In any case, it needs to be a case of involving the broad community, rather than having a rigid plan. Charles Matthews 10:45, 28 Jan 2005 (UTC)

I agree, with both the most recent posts above. Sounds almost like a (broad, community-based and certainly not rigid) plan... Ben Cairns 12:59, 28 Jan 2005 (UTC).
Now, I think what I understand from what Charles said is the following (I could be wrong, but this makes sense to me): We should make a list of PlanetMath articles, or maybe several lists, grouped by subject area, as there are many articles there. Each element in the list should have several things. First, very importantly, the title of the PlanetMath article, second, the title of the corresponding Wikipedia article(s) if any, third the status of the Wikipedia article as compared to the Planet math one (say, "WP article is just a copy of the PM article", "WP article is better than the PM one", "Some merger recommended (which way)", etc). This comment thing is very important, because people seeing this can decide what to do, and update the status line after they took action. This also implies that the status comment must be signed (four tildas) by the user who did the comparision, so that after a long enough time another comparison is made.
What do you think? Now, the first element on each list entry, the PM article title, can be easily auto-generated, and new elements in the list can be easily added automatically later as new articles show up on PM. The second and third elements for each entry will need to be community based, as will take a huge effort to comment on thousands of articles. Oleg Alexandrov | talk 16:06, 28 Jan 2005 (UTC)
This is what I was planning on doing. There will be a lot of grunt work by users that needs to be done. CryptoDerk 16:51, Jan 28, 2005 (UTC)
Something like this seems reasonable. Paul August 17:46, Jan 28, 2005 (UTC)

I'm not sure this is a good idea. Don't get me wrong, I love PlanetMath. But a world in which there is only one comprehensive open-content math reference is not as good as one in which there are two. -- Walt Pohl 16:37, 28 Jan 2005 (UTC)

User:akrowne (the PM creator) was receptive of the idea, and I think he may have even been the one to approach ME about it a few months age, although I'd have to dig through my IRC logs. Similarly, he plans on grabbing some WP content and using it in PM. I do think that even with content exchange the two will serve different audiences. You've got people who might prefer the author control, setup, and community of PM, and PM has growing sections on things that WP doesn't offer — such as papers, books, and expositions. CryptoDerk 16:51, Jan 28, 2005 (UTC)
I think PM and WP can share content and remain independent. Paul August 17:46, Jan 28, 2005 (UTC)
But what's the point? It's not like either Wikipedia or PlanetMath are hard to find. They both score high in Google searches. So it doesn't help readers any. Maybe someone would have come along and written a great new potential theory article. Now we just have the same text in two different places. What good did it do?
I think a better idea for a project would be one to make sure that Wikipedia has an article for each PlanetMath article, and that each Wikipedia article links to the appropriate PlanetMath article. Actually duplicating the content seems pointless to me. -- Walt Pohl 20:33, 28 Jan 2005 (UTC)
Well, I think for one it can help fill in some red links. Plus, getting content from other places is, at the very least, a good starting point for building our own. Also, in the case of articles we already do have, we can make them better. WP integrates other free content (PD images, 1911 EB), so why not this? CryptoDerk 20:53, Jan 28, 2005 (UTC)
PD images are obviously a good idea, but I think Wikipedia has been ill-served by including material from things like the 1911 EB. Most pages based on 1911 EB entries are either terrible, or have been so completely rewritten that you couldn't tell they ever used EB. A couple of the math pages has history copied from an old public domain source, and they just sit there, undigestible lumps of text that no one really understands and everyone is afraid to edit. I don't think that will be a problem with PlanetMath, but inclusion of 1911 EB material is not an inspiring example. -- Walt Pohl 01:59, 29 Jan 2005 (UTC)

OK. Draft up at User:CryptoDerk/planetmathproject. Feel free to comment and change it. CryptoDerk 18:03, Jan 28, 2005 (UTC)

See User talk:CryptoDerk/planetmathproject how an automatically generated list of articles from Planet Math looks. Does not look optimistic. Oleg Alexandrov | talk 02:59, 29 Jan 2005 (UTC)

Notice: Wikipedia:WikiProject Mathematics/PlanetMath Exchange is now the location for this project. Active discussion is also going on here: Wikipedia talk:WikiProject Mathematics/PlanetMath Exchange. Additionally, when it goes live we should include a link to it from the main WikiProject Mathematics page. CryptoDerk 16:51, Jan 30, 2005 (UTC)

(I took the liberty editing the above notice to add a link to the talk page. Paul August 17:27, Jan 30, 2005 (UTC))

Where to contribute math articles? Wikipedia or Planet Math?


I'm a newcomer here.

User:Oleg Alexandrov has insinuated on multiple occasions that the math articles that I write are far too complex and complicated for Wikipedia, and most recently suggested that I contribute to PlanetMath instead. I would like to get a clear statement from the Wikipedia math community whether this is indeed the key difference between Wikipedia and PlanetMath, and whether it really is the Wikipedia policy that practicing scientists/academics are encouraged to work on PlanetMath, leaving lay topics for lay authors on Wikipedia.

I am rather discouraged and disappointed; I wish I'd been told this *before* I got involved in wikipedia, and not after, as I have already invested a good bit of time in the enterprise, and its seems that it may all have been for naught.

I am also confused by Oleg's stance on this issue, as almost every math article in wikipedia seems (to me) far more complex and advanced than those which I write. For example: the list of articles that I've started or made major revisions to is here: User:Linas#Misunderstanding things; essentially all of these deal with undergraduate mathematics topics that some typical undergrad math major might encounter in school. By contrast, wikipedia has massive and massively complex articles such as Artin conjecture and Jet bundle and Banach space and Lattice (order) and Sheaf and Scheme (mathematics) which are not only advanced graduate-level topics, but are areas of active academic research. So this simple math /complicated math division leaves me perplexed.

My goal in writing for wikipedia was to have something to replace my paper copy of Abramowitz & Stegun: simple, concise, informative, filled with facts that you never knew or had forgotten, the universe of math at your fingertips. Just plain-old straight-ahead stuff, nothing fancy.

I think a clear editorial policy for acceptable content for math articles for wikipedia should be spelled out up front; if complexity is really an issue, then I strongly encourage a mass migration of the advanced math articles out of wikipedia and into planetmath, where they can serve some actual, useful purpose, instead of splitting the community between two wikis.

linas 06:04, 29 Jan 2005 (UTC)

Now I am in hot water. What I had mentioned to Linas was about style, not content, see character group for style which I don't quite like. But oh, well, it is good this topic is raised. What is a good Wikipedia aricle? I would also need that for the Wikipedia:How to write a Wikipedia article on Mathematics with which I am struggling. Oleg Alexandrov | talk 06:13, 29 Jan 2005 (UTC)
Hi Linas, I agree with you; Wikipedia should have as much "notable" math as possible. Please don't move to PlanetMath. "The universe of math at your fingertips": exactly! Wikipedia is not paper. We can always organize a subject so it has an easier overview with more detail later or in a subarticle. dbenbenn | talk 07:34, 29 Jan 2005 (UTC)

On further thought, I realize that I am (perhaps like everyone) using Wikipedia (and the web in general) in two very different ways, and that this is the source of the problem. When I am reading about a topic about which I know very little e.g. Banach space, I find the "lots of words; few formulas" approach to be excellent, as it lets me learn the subject quickly and painlessly. However, once I know the topic very well, I find that the words get in the way of the formulas: they start hampering understanding, not helping. They mislead, they are inexact intellectually, they clutter the page visually. The articles that I am contributing to wikipedia are mostly on topics I feel comfortable with; ergo, I like them better when they are mostly formulas with few words ... that is, reference articles in the style of Abramowitz & Stegun ... or my recent Christoffel symbols. I see the need in the world for both styles: the introductory article, and the compendium/reference. Now, how to resolve that tension in an editorially pleasing way? linas 07:48, 29 Jan 2005 (UTC)

Thus, perhaps, I nominate a new article style (and article naming convention), the style being called "reference" and the naming convention being that if "XYZ model" is the article that provides intro and examples and generalities, then "XYZ model (reference)" would be the long, exhaust(-ive/-ing) list of theorems and formulas. That would resolve several ugly pages I've been struggling with. For example, Upper half-plane is a prime candidate for this kind of split.linas 08:00, 29 Jan 2005 (UTC)

Linas - I don't think there is any problem with the level of the articles that you have started - the ones I have seen are, as you say, at the level of standard undergraduate mathematics. As for style, this will always be a largely subjective matter. A mathematical article that starts out as a concise summary of defintions and main results may be seen as a skeleton by other contributors, who will add introductory material, history, motivation, examples, applications etc. Eventually the article may become so large that the original neat skeleton is lost to sight, and the article needs to be re-arranged or maybe even re-factored. This is all part of the dynamic, open and collaborative nature of Wikipedia.
As an aside, I notice that the "ownership models" in Wikipedia and PlanetMath seem to be rather different. In the Wikipedia ownership model, an article does not have a single owner, and all users have free access to all articles. I understand (from reading [1]) that the default ownership model at PlanetMath is that an article has a specific owner (usually the person who started the article), and the owner must review each proposed change to that article, and may reject changes that they disagree with. It would be interesting to see if this leads to differences in the style, level and coverage of articles at the two sites. Gandalf61 10:33, Jan 29, 2005 (UTC)

I don't see that there is any overall feeling about level of WP articles, on mathematics. There was once a consensus that we were speaking to undergraduates with a year or so of university work behind them. That was just an indication; textbook material, as such, should be in Wikibooks. All one can really say, is that additions to a given article should in some sense match the approach there: any sudden changes of level can be unnecessarily confusing to readers, and should be flagged in some way, such as 'from the point of view of complex analysis' if one is switching away from a real-variable calculus topic.

Linas, I think you shouldn't generalise too much about this. There is certainly room here for any contributions of almost any level, if they integrate properly.

Charles Matthews 16:44, 29 Jan 2005 (UTC)

Linas: Please don't leave. From what I see, your contributions have been valuable and appropriate. Wikipedia is meant to be comprehensive. It should contain all of "notable" mathematics, from the general and introductory to the technical and advanced. "The best way to organize and present all this is not as clear. As Gandalf61 says, Wikipedia should provide "introductory material, history, motivation, examples, applications etc", Wikipedia can accommodate several overlapping and interrelated articles dealing similar subjects, see for example, this constellation of set theory articles:, set, subset, set theory, Naive set theory, Axiomatic set theory, Algebra of sets and the as yet unwritten History of set theory, Motivations of set theory, Applications of set theory, Frontiers of set theory, etc. See also the above discussion "Graph (mathematics) vs Graph theory". So something like what you suggest might be appropriate, but should probably be discussed some more, with some examples. Paul August 17:03, Jan 29, 2005 (UTC)

MathWorld references

So many mathematical articles reference MathWorld that I decided there should be a reference template, similar to Template:Book reference or Template:imdb title.

{{MathWorld | urlname=HappyNumber | title=Happy Number}}


Weisstein, Eric W. "Happy Number". MathWorld. 

Feel free to edit the template if you feel strongly about the form of the citation. (I purposely decided not to follow Weisstein's referencing instructions. I think "A Wolfram Web Resource" is a bit much.) What do people think? Start using it in math articles? dbenbenn | talk 04:31, 29 Jan 2005 (UTC)

I like it. I'm actually surprised we didn't already have one :o CryptoDerk 04:52, Jan 29, 2005 (UTC)

Main problem is that not all the MathWorld articles are written by Weisstein. Tompw 15:48, 29 Jan 2005 (UTC)

Yeah, I've noticed that too. They still say that Weisstein should be credited as the author, though. It isn't clear to me what kind of license they use at MathWorld for submissions; I suspect it's something like you transfer your copyright to them.
Do you think, for example, that a reference to Petersen Graph should credit "Pegg" as the author? I'm inclined to not bother; but if it's an issue, feel free to make another template, say Template:MathWorld author that would take a third parameter. dbenbenn | talk 20:48, 29 Jan 2005 (UTC)

Wikipedia:WikiProject Mathematics/PlanetMath Exchange -- version 0.1 -- comments requested (on this page)

Introducing the new subproject of WikiProject Mathematics:Wikipedia:WikiProject Mathematics/PlanetMath Exchange. Before you jump there, let me describe what to expect.

We have a purpose section, an instructions section, and the list of subjects in mathematics (according to AMS Subjects classification). Each subject list will contain the titles of all PlanetMath articles on that subject (automatically generated). For now, all lists are red links, except for Functional analysis, scroll down the page for that.

This is done on purpose. There is enough stuff to give people an idea of what to expect, and we are in preliminary enough stage that everything can still be modified.

I would like to invite people to share their thoughts here. Some of us believe that this project, rather than making Wikipedia a clone of PlanetMath, or the other way around, will instead benefit both of them. Oleg Alexandrov | talk 06:11, 31 Jan 2005 (UTC)

By way of summary, some of the things which have been discussed on Wikipedia talk:WikiProject Mathematics/PlanetMath Exchange) and tentatively agreed upon there and/or accomplished are:

  1. We should go forward with this project.
  2. The project name should be: "PlanetMath Exchange".
  3. It should be a subproject of this project with the project page at: Wikipedia:WikiProject Mathematics/PlanetMath Exchange. A first draft of that page now exists there,
  4. There should be an auto-generated list of all PlanetMath articles. The first auto-generated list of PlanetMath articles has been created here: Wikipedia:WikiProject Mathematics/PlanetMath Exchange/46-XX Functional analysis.
  5. There should be a template created to facilitate the creation of a link to the appropriate PlanetMath article in any newly created WP article based on a PM one. Such a template has been created: Template:planetmath. Additionally Template:planetmath reference has been created for a general reference.

Comments? Paul August 06:20, Jan 31, 2005 (UTC)

Note: I modified #5 to include the other template as well. CryptoDerk 06:29, Jan 31, 2005 (UTC)

Begging the question

I'd like to point people to the mathematical remark in the article Begging the question. See also my comment on the talk page which has thus far generated no responses. There's gotta be a better example than either of these two. - dcljr 06:01, 9 Feb 2005 (UTC)

New Mathematics Wikiportal

I know I've posted this on most of your user talkpages, but I felt it was important to add to the project page as well.

I wanted to point out to you the new Mathematics Wikiportal- more specifically, to the Mathematics Collaboration of the Week page. I'm looking for any math-related stubs or non-existant articles that you would like to see on Wikipedia. Additionally, I wondered if you'd be willing to help out on some of the Collaboration of the Week pages.

I encourage you to vote on the current Collaboration of the Week, because I'm very interested in which articles you think need to be written or added to, and because I understand that I cannot do the enormous amount of work required on some of the Math stubs alone. I'm asking for your help, and also your critiques on the way the portal is set up.

Please direct all comments to my user-talk page, the Math Wikiportal talk page, or the Math Collaboration of the Week talk page. Thanks a lot for your support! ral315 02:54, Feb 11, 2005 (UTC)

ral315: This is a better way to communicate to the Wikipedian mathematics community, rather than posting on everybody's talk pages — some people consider that to be spamming. Your portal looks interesting. I'll put in on my watchlist and lend a hand as time and interest permits. As for mathematics articles needing attention check out Wikipedia:Pages needing attention/Mathematics. Paul August 06:27, Feb 11, 2005 (UTC)
As I said on User talk:Ral315#Wikiportal, personally, I really appreciated the note you left on my talk page. It might have been months before I'd have found the portal without it, as I'm much more active in other areas right now. And over the years, whenever I've taken the trouble to identify the people I thought would be interested in something and give them each a personal heads-up on it, I've only ever had thanks. But within Wikipedia there are many sub-communities, and this one seems not to like it. I've noted that now, and I'm sure you have too. I'm not convinced it's representative of the whole of Wikipedia, or even the Maths community, but certainly take it as applying to the more active members of this Wikiproject. Andrewa 13:05, 11 Feb 2005 (UTC)

Tex rendering -- help!

Can someone sort out my TeX rendering at effective population size please? I have most of it, but I'm not sure how to group subscripts/superscripts together e.g. p [sub] 1 + q [/sub] sort of idea. Dunc| 15:03, 25 Feb 2005 (UTC)

Oh, I sorted that one myself. But I'm still stuck on having a fhat [sub]foo[/sub] because they won't go together, which leaves a gap and {} don't seem to work ?!? Dunc| 15:26, 25 Feb 2005 (UTC)
Fixed. dbenbenn | talk 20:38, 25 Feb 2005 (UTC)

binomial expansion of (p_1 + ... + p_n)^c

I've asked this on Wikipedia:Reference_desk#.5B.5Bbinomial_expansion.5D.5D too, but, what is the binomial expansion of ? I don't think this is covered in the articles that are there at the moment. (I want to derive the fully general Hardy-Weinberg law). Dunc| 19:22, 2 Mar 2005 (UTC)

Assuming c is an integer > 2, refer to the multinomial theorem. Charles Matthews 20:52, 2 Mar 2005 (UTC)

\phi or \varphi

It seems to be the norm on wikipedia to use for writing one of the angle coordinates in spherical coordinates. I think that it is usually the norm to use in mathematics and physics. I'd be willing to go through and change a bunch of the pages that use \phi to use \varphi instead. But I don't want to go against established policy. It just seems to me that the 'pedia should use the conventions that are common in mathematics. Has there been discussion about this issue before?

--Jacobolus 06:01, 6 Mar 2005 (UTC)

I believe the Wikipedia norm is the correct one. Dysprosia 06:19, 6 Mar 2005 (UTC)
As do I. Surely, it's a case of using one letter followed by another: theta () then phi (). If varphi () were correct, surely we'd use vartheta () for the first angle we designate? --stochata 13:32, 6 Mar 2005 (UTC)
I think that the "var" in "\varphi" just means "variant phi symbol", and doensn't necessarily imply that "\vartheta" should be used for theta. In all of the math books I just looked at (many of which are layed out in TeX), spherical and cylindrical coordinates were laid out using varphi. In the two physics books I looked at, the phi symbol was used. So I'll stick with phi I guess, as it appears (see discussion below this one) that the physicists' notation is winning out for other coordinate systems. --Jacobolus 18:19, 6 Mar 2005 (UTC)
I use \varphi when I write mathematics in TeX (In fact, I \let\phi\varphi), but I prefer \phi here. The wiki software is able to display \phi as an actual character, whereas it generates an image for \varphi. dbenbenn | talk 17:59, 6 Mar 2005 (UTC)
One pesky problem is that in many html fonts, phi displays inline as the varphi symbol, which means that there is visual inconsistency between rendered formulae and inline variable names. --Jacobolus 18:19, 6 Mar 2005 (UTC)
Note that in my comment below on the notation used by mathematics tutors for my undergrad -- I link to their book. They use phi rather than varphi. (Indeed, Jacobolus, the inline phi appears as varphi on my browser) --stochata 11:58, 8 Mar 2005 (UTC)

use of phi and theta in spherical coordinates

Hi all. I noticed recently that the articles on Vector fields in cylindrical and spherical coordinates and on Nabla in cylindrical and spherical coordinates have theta as the polar angle, phi as the longitude angle, r as the length of the vector, and rho as the length of the vector projected into the plane. In the article about Coordinates however, these uses of phi and theta, and respectively rho and r, are switched. This seems unnecessary conflict. I realize that physicists don't agree with mathematicians on the correct order of these terms, but at least some explanation should be given for the unwitting visitor, who might otherwise be very confused to see rho's and r's swapped so casually.

And then, some consistent drawings of coordinate systems and vector operations, etc. in these coordinate systems should be made. Here's my drawing of spherical coordinates: Image:Spherical_Coordinates.png. I'd be willing to make more drawings. But first some decision should be made about which convention to follow. That used in math or that used in physics.

Tied to this issue is my previous question about varphi and phi. Is one preferred as a coordinate name?

--Jacobolus 08:16, 6 Mar 2005 (UTC)

It should be only a matter of picking one standard and sticking to it. Dysprosia 09:49, 6 Mar 2005 (UTC)
I have never noticed a difference! I was taught to use theta, phi, r in my mathematics lessons at school, and later simply continued to use it through a physics degree. Which do we suppose is used by which category of people? (And maybe country of origin also affects the system used!) --stochata 13:38, 6 Mar 2005 (UTC)
I would agree with stochata that r is the prefered notation for the length of the vector, and so then ρ is the projection. And I agree with Dysprosia that consistency is what matters above all. So since you raised this issue, could you go through the pages using spherical coordinates, (like start at spherical coordinates, see what links there, etc), and change the notation in those places to keep things consistent? That would be much appreciated.
About the picture, I like it. Just one small remark. You will need to of course use a scaled version of it. In the scaled version you will need to make sure the fonts are the right size, and that aliasing is not too bad (pictures which have thin lines and thin curves tend to look ugly unless antialiasing is employed in some way). Oleg Alexandrov 16:24, 6 Mar 2005 (UTC)

I would argue in favor of the usage in Vector fields in cylindrical and spherical coordinates. Where

  • (r, θ, φ) are spherical coordinates with θ being the colatitude (angle with the positive z-axis) and φ the azimuthal angle.
  • (ρ, φ, z) are cylindrical coordinates with φ the azimuthal angle

The reason is that this usage is almost universally used by physicists. I think the reason stems from the fact that this is the notation used in Jackson's Classical Electrodynamics — the de facto textbook on electodynamics, where these coordinate systems are heavily utilized. Mathematicians may differ in their usage, but at least this way we include many mathematicians and nearly all physicists. -- Fropuff 17:34, 2005 Mar 6 (UTC)

Ok. So the notation used in Jackson and Griffiths and elsewhere in physics will be the norm. I'll make a prominent note at the top of the Coordinates (elementary mathematics) page (Aside: why is this called "elementary" mathematics... maybe just Coordinates (mathematics) would be better??), and then go with the physics notation. One last question. For inline text, is using the <math> and </math> tags frownned on? I've seen conflicting reports, and the usage seems to vary greatly between articles. I would generally be inclined to use them, but I'll try to stick to whatever the accepted standard is. --Jacobolus 18:12, 6 Mar 2005 (UTC)
One could argue that coordinates (mathematics) should discuss coordinates on arbitrary manifolds (or even more general spaces, i.e. with singularities). As far as inline TeX goes: the reason we try to avoid it is that the inline PNG's are too large and look bad with the surronding text. There has been lengthy arguments about this (see /Archive4(TeX)) and not everyone agrees. -- Fropuff 19:04, 2005 Mar 6 (UTC)
I've just checked the book by my undergrad tutors [2], and they certainly use theta, phi, r for spherical polars (and phi, rho, z for cylindricals as Fropuff suggests). Note that Riley was originally from a mathematics background. --stochata 11:55, 8 Mar 2005 (UTC)

My 2 cents: I am a mathematician, and I prefer the physics/engineering convention for several reasons.

Foremost is that, despite the beliefs of many ignorant American mathematicians and the usage of almost every American calculus textbook, the physics/engineering convention is simply by far the most widely-used convention of the two, throughout the world. It is the convention for virtually all (American and non-American) scientists, and for many, if not most, non-American mathematicians. American mathematicians are really the only group of users who enjoy a majority POV on this issue; it is only because of calculus textbooks that the whole world does not agree.

My second reason for favoring the physics/math convention is that it has far deeper historical origins in physics and science than the American usage does in math. The effort required for Americans to change would be far less than the effort required to re-write classical physics texts.

But, my most important reason is that the American convention is fundamentally flawed from a mathematical viewpoint. If this were simply a matter of two symbols getting interchanged, that would be one matter. But the American convention produces a left-handed coordinate system, and I don't think I need to explain why that poses a tremendous problem.

I taught a vector calculus class a couple years ago, doing something perhaps against better judgment -- teaching the non-American convention while the text used the American one. Of course, I also freely used differentials and the type of informal arguments physicists use for deriving tangent vectors, and so forth. I just made sure that I never assigned any problem using the textbook convention, and I told them not to read that part of the text. There wasn't too much confusion resulting, I mean, at least among those who weren't already confused by the time we reached general coordinate systems. Revolver 07:17, 12 Apr 2005 (UTC)

Relevant proposed naming convention: ambiguous adjectives

There is a proposal at Wikipedia talk:Naming conventions (ambiguous adjectives) that could affect several mathematics articles. -- Toby Bartels 08:40, 2005 Mar 7 (UTC)

Soliciting input on Estimation theory

Just seeking input on a new article: estimation theory. (Estimation didn't take a purely statistical explanation and I better know it as estimation theory.) Please leave article specific commentary on it's talk page instead of here. Thanks. Cburnett 06:56, 8 Mar 2005 (UTC)

straight or italic d?

What are your opinions about the use of upright d versus italic d in integration and for the exterior derivative? Currently, probably because it is less LaTeX, italic d seems predominant. Personally I prefer upright d as this more clearly contrasts with possible use of d as a function or number(distance). Examples

Also, when defining something, do you use := instead of = and why? MarSch 17:30, 11 Mar 2005 (UTC)

It is standard to use italics for differentials such as dx (e.g., see Wolfram: [3]). The spacing ought to give you a clue to the nature of the symbol, note that you should add a little space to distinguish the variable (see Lamport p.50). e.g., . --stochata 23:35, 11 Mar 2005 (UTC)
I like the idea of using a vertical "d", but it is not common. I think that in Wikipedia we are not supposed to be trend-setters but should follow common practice, so we have to use the italic ''d". --Zero 02:22, 12 Mar 2005 (UTC)

It's my estimate that this is largely a US/UK thing (with Americans using italics and the Brits using an upright shape). Personally, I prefer to use both a thin space and an upright shape -- why be coy? (I've added a row to the determinant example, so that we can all see what all four possibilities amount to there.) As usual, I oppose any sort of policy decision for all articles; we should follow the usual rule of tolerance for variation that applies to US/UK spelling differences. -- Toby Bartels 23:56, 2005 Mar 12 (UTC)

Toby, I am British (and currently in Britain) and I prefer the italic version (although I have seen the upright 'd', it doesn't strike me as that common -- although my area doesn't tend to use derivatives that much). I look forward to articles with phrases such as "dx, or dx in American mathematics" :-) --stochata 12:18, 13 Mar 2005 (UTC)

The Brits have spoken. :) I would say we need to restrict transatlantic differences to spelling (and politics) only. Italic dx has been the style on Wikipedia, and I think it should stay this way. Oleg Alexandrov 19:45, 14 Mar 2005 (UTC)
Shades of varphi! I think its a terrible idea to go out and try to retroactively edit hundreds of pages to use a different font in the math typsettings. Authors of new pages get to pick thier symbols, but they should make at least token attempts to be consistent with nearby articles. For the record, I have no love for := I sometimes use in the privacy of my own room, but I would not subject the public to such degradations. One man's definition is another man's theorem. linas 16:21, 14 May 2005 (UTC)
My vote goes to "thin space (/,) and upright d", for better semantics and for all the other reasons mentioned here PizzaMargherita 07:06, 1 December 2005 (UTC)

Reformat of Participants list

I'm thinking about changing the format of Wikipedia:WikiProject Mathematics/Participants, making it into a table like so:

User (T1 C2) Areas of interest Comments
Andrewa (T C)
AxelBoldt (T C)
Charles Matthews (T C) I've added about 300 mathematics pages, many biographies, and lists of mathematical topics. I now also work on other areas of WP, but a well-organised and credible collection of mathematical articles is very much what is needed. We now pretty much have the house style and topic classification in place; there are some missing areas, and a great need to explain current research areas, as well as good history. I'm a sysop - one of not too many on this list.
Chas_zzz_brown (T C) abstract algebra, group theory My knowledge of topics outside of group theory is a monotonically decreasing function of their relationship to abstract algebra.
Mark Dominus (T C)
FunnyMan3595 (T C) abstract algebra I'm a freshman majoring in mathematics, but I already have quite a few courses under my belt. My specialty is abstract algebra.
irrªtiºnal (T C) Let ε < 0 (hehe...) I am a highly unsuccessful mathematician. I am a man. I am single. I am free. I am an existentialist, therefore I am not.
Jeff (T C) dynamical systems, complex systems, real analysis I love to edit.
Kevin Baas (T C) I started the fractional calculus section. Though it is still embryonic, it is very much 'my style', which is still under development. -Also started Information geometry section. I am just learning about this, though.
Ling Kah Jai (T C) I have contributed an interesting article called last stone game.
LittleDan (T C) geometry, group theory, vector spaces I know up through geometry, and a fair amount of group theory and vector spaces. I can usually pick things up from wikipedia articles, if not from mathworld, then I can edit wiki articles for clarity.
Markus Krötzsch (T C) I think many math articles still lack: general intros/motivation, links to relevant literature, objective account of alternative definitions (even if one definition is prefered in Wikipedia).
MarSch (T C) geometry, category theory, physics
Miguel (T C) How come Toby didn't tell me about this?
Pierre Abbat (T C)
Ram-Man (T C)
Revolver (T C) Hi, I'm back.
Taku (T C)
Toby Bartels (T C)
Tomo (T C)

Notes: 1 User's talk page; 2 User's contributions

Any comments? Paul August 22:40, Mar 11, 2005 (UTC)

Much better, go for it -- so long as people aren't scared off to add their own entry. --stochata 14:36, 13 Mar 2005 (UTC)

Yes I had wondered about that. Figuring out the table syntax might discourage some. Although, perhaps we could consider a kind of IQ test, sort of like figure out the next term in this sequence … ;-) I'd be willing to write some instruction and/or provide a template. What do others think? It is a bit of work, so I don't want to undertake it if it is not deemed useful, or if we think it will put people off unnecessarily. Paul August 14:49, Mar 13, 2005 (UTC)

Well, trying to overcome the apathy...
I am against the table. I never learned the syntax of the Wiki table (all those absolute value signs everywhere :) and never plan to. And I don't see the gain of the table, besides the obvious rosy background. :)
Other thoughts? Oleg Alexandrov 16:21, 13 Mar 2005 (UTC)
PS And the background ain't even rosy! :) Oleg Alexandrov 16:21, 13 Mar 2005 (UTC)

Well I guess the main advantage of the table, in my mind, is that it encourages participants to enter fields of interest, plus it is eaisier to read, and I think the links to the user's talk page and contributions is helpful, for me at least. I'd be glad to help anyone with the syntax — or add a "rosy background" if that would help ;-) (Oleg: tables are fun! :) Paul August 16:56, Mar 13, 2005 (UTC)

I like it. Tomo 23:21, 13 Mar 2005 (UTC)

OK, although the response has been somewhat limited, I've decided to go ahead with the new format. Three users have expressed support, stochata, Tomo and MarSch (on my tak page). Oleg's was the only dissenting voice, but he has since warmed up enough to the idea to create a script to generate the table from the existing list ;-) So he is hoist on his own Perl petard, so to speak ;-) I would have preferred to have heard from some of the more senior participants (Charles Matthews, are you listening? ). Hopefully people are at worst indifferent. If anyone doesn't like it we can always revert it ;-) Paul August 21:41, Mar 18, 2005 (UTC)

"monotonicity" merged with "monotonic function"

After some discussion on talk:montonicity involving me, Toby Bartels, Michael Hardy, and Markus Krötzsch, it was agreed that monotonicity should be merged with monotonic function, which I have now done (monotonicity now redirects to monotonic function).

However there was a bit on a generalized notion of convergence for function between posets, which Toby thinks is worth keeping, but which I don't think necessarily belongs in the monotonic function article. Toby has suggested that perhaps it should be moved to its own article titled "order convergence". I made a stab at converting the orphaned text into a first draft for such an article (see: talk:montonicity) but I'm unfamiliar with this concept and am reluctant to actually create the new article myself. So If anyone knows anything about this, and would like to salvage this now orphaned content please do so.

Here is the text under discussion:

(Beginning of quoted text)

The notion of monotonicity allows one to express the principal instances of convergence (to a limit):

Given that a commensurate difference relation is defined between the members of S; that is, such that for any four (not necessarily distinct) members g, h, j, and k of S, either g − h ≤ j − k, or g − h ≥ j − k, and given that M from T to S is a map of equal monotonicity, then the values M(s) are called converging (to an upper limit), as the argument s increases, if either:

  • the set T has a last and largest member (which M maps explicitly to the corresponding limit value l in set S); or
  • for each member m of T, there exists a member <n > m such that for any two further members x > y with y > n, M(n) − M(m) ≥ M(x) − M(y).

As far as the set of all values M(s) does therefore have an upper bound (either within set S, or besides), and as far as every set which is bounded (from above) does have a least upper bound l, the values M(s) are called converging to the upper limit l as the argument s increases.

Similarly one may consider convergence of the values M(s) to a lower limit, as the argument s decreases; as well as convergence involving maps of opposite monotonicity.

(End of quoted text)

Paul August 21:13, Mar 14, 2005 (UTC)

Algebraic solution

Could someone here confirm that this new one sentence article is correct? An algebraic solution is a solution that is either a number or can be computed. That strikes me as so general as to be essentially meaningless, but google's been no help & I'm not competent in this area. Thanks. Michael Ward 03:06, 18 Mar 2005 (UTC)

It seems the definion does not make sense unless the term computation is explained. Maybe one should add a reference to or redirect to algebraic number or algebraic equation. Tomo 06:54, 18 Mar 2005 (UTC)

I've redirected this to closed-form solution. Charles Matthews 08:34, 18 Mar 2005 (UTC)

periods at the end of formulas -- request for comment

This is an edited version of my conversation with Omegatron, about periods at the end of sentence. I just wonder, what are your opinions about this? Thanks!

Is there a consensus that [period] is needed? looks bad to me. - Omegatron 00:19, Mar 19, 2005 (UTC)

I wonder if the reason it looks bad has to do with a peculiarity of using TeX on Wikipedia, as opposed to using TeX in the usual way. That is that if you put the period or comma outside the math tags, it gets mis-aligned. If you put it inside, however, it looks good. Michael Hardy 23:45, 19 Mar 2005 (UTC)
Period at the end of formula is the universal style in math. I am aware that in engineering for example, people do not do that. Did it happen that I modified something outside math (I try to stick to math, but sometimes the links from the list of mathematics topics lead into related subjects). If you would like, we can have a wider discussion about this. Oleg Alexandrov 00:24, 19 Mar 2005 (UTC)
Yeah it was an electronics article common drain, and they weren't sentences, either. I think even in mathematics articles it doesn't look good. I don't remember seeing it in my math books. It looks like a symbol, which could certainly confuse me; I don't know about other people. Perhaps it's something from typesetting that doesn't carry over perfectly to the web? - Omegatron 00:30, Mar 19, 2005 (UTC)
I just pulled two math books off my shelf (math math, not engineering math) :-) and they are different. One has no punctuation next to formulas unless they are inline with the sentence. The other has periods the way you are using. - Omegatron 00:35, Mar 19, 2005 (UTC)
I just randomly pulled 5 applied math and probably books off my shelf. They all use period at the end. Would you like us to discuss this at Wikipedia talk:WikiProject Mathematics. Or would you take my promise that I will not mess up with any articles which are not either linked from list of mathematics topics, or in some math category, or listed as a math stub? Either way is very fine with me. Oleg Alexandrov 00:41, 19 Mar 2005 (UTC)
The encyclopedia of physics uses periods, too.  :-) You are winning my bookshelf 2 to 1 so far. The engineering books don't, as you said. - Omegatron 00:42, Mar 19, 2005 (UTC)
If it's standard mathematics practice I guess go for it, and leave the engineering articles without. Of course, there are some articles that exist on the intersection between these two worlds. Has there been any discussion about it before you started adding them? - Omegatron 00:44, Mar 19, 2005 (UTC)
No, I did not consult anybody [about this]. But, I am already at letter "C", and at at least 5 Wikipedians I know had one or more of those on their watchlist (well, I assume so, as they contributed to those). I can certainly stop until we talk this over at Wikipedia talk:WikiProject Mathematics. All up to you. Oleg Alexandrov 00:47, 19 Mar 2005 (UTC)

Let's just move this conversation there and see what other people have to add, and you can keep going with the math articles. - Omegatron 00:49, Mar 19, 2005 (UTC)

I don't care for them when the formula is on its one line (I see a lot of "cleanup" on my equations). Inline with sentences is fine like this . But the period *not* inside the math tags. Cramér-Rao inequality is mixed with and without periods: Cramér-Rao inequality#Single-parameter proof doesn't but Cramér-Rao inequality#Multivariate normal distribution does.

In the end, I don't see you can really justify either no more than if why it should be Jones' or Jones's. Entirely style. Cburnett 02:13, 19 Mar 2005 (UTC)

I did not get to Cramér-Rao inequality yet. I think one needs to be consistent at least on a per-page basis. Oleg Alexandrov 02:33, 19 Mar 2005 (UTC)
That's primarily from one section having already been there. Might as well wait and see what results from this discussion. :) Cburnett 04:33, 19 Mar 2005 (UTC)

Yes, this is standard style in mathematics textbooks. But on screen I think it looks clumsy, is potentially confusing, and is unnecessary - I think the effect on continued fraction, for example, has not improved the article. My vote would be not to do this - and certainly to stop until you have a consensus. Gandalf61 13:46, Mar 19, 2005 (UTC)

I am reluctant to comment on this rather trivial matter, but I think the convention to treat formulas as part of the text for the sake of punctuation rules is useful and logical, and widespread in maths style guides. So I support Oleg's efforts. I don't see Gandalf's point that there is a distinction between maths in books and maths on the screen in this matter. -- Jitse Niesen 15:36, 19 Mar 2005 (UTC)
Agree. Charles Matthews 17:20, 19 Mar 2005 (UTC)
Also agree. Now may I get a pardon from Oleg for being one the worst offenders against this commandment? CSTAR 18:56, 19 Mar 2005 (UTC)
Penance required - start the Weil representation article ... Charles Matthews
OK, OK I suppose that's better than saying 500 padre nuestros.--CSTAR 18:00, 11 Apr 2005 (UTC)

From User talk:CesarB

I am now doing myself a bad service, but there is discussion going on at Wikipedia talk:WikiProject Mathematics about period at the end of formula if formula is at the end of sentence. So, you can go there and put your vote (which will be against me). I would like to ask you to specify there your background. It seems that mathematicians are mostly for period at the end of formula, while engineers (and now I see, computer scientists) are against.

In the future, I will avoid modifying non-math articles, like bra-ket notation, which is physics. I try to stick to math, but sometimes non-math articles (again, like bra-ket notation) are put in a math category, and then this kind of disagreements arise. Cheers, Oleg Alexandrov 19:42, 19 Mar 2005 (UTC)

I don't care either way, as long as it's obviously separate from the formula (like a big fat period). You not only added a period which looked like part of the formula, but you added it inside the <math> tags, which made it even more like part of the formula. cesarb 19:45, 19 Mar 2005 (UTC)
Often all it takes is to precede the period by a little bit of space and it no longer intrudes on the formula. --Zero 12:07, 20 Mar 2005 (UTC)
Agreed. Of course, how much space is needed depends on the formula (a formula full of whitespace would need more space than a formula with no whitespace at all). cesarb 13:42, 20 Mar 2005 (UTC)
I am for proper punctuation of formulae. BTW the bra-ket article is a really bad example IMHO, since it has lots and lots of miniscule formulae, which would probably benefit from inlining.MarSch 15:27, 20 Mar 2005 (UTC)

Period before or after </math> -- please comment on this as there are opinions on both sides.

It seems that the opinion leans (I would say overwhelmingly) towards putting period at the end of formula. There are situations in which there needs to be some space between formula and period, and in some situations one could be better off without a period if that would confuse things, but these are rather special cases, when careful and individual judgement needs to be made.

There is another quite dividing issue which needs to be settled. Shoud the period before or after </math>?

I would agree with Michael Hardy that the period should be before </math> so that it becomes part of the PNG image. Otherwise, if the period is separate, if the formula is at the edge of browser window, the period moves to the next line. Also, this introduces a big space between formula and period (and comma) which can look quite unnatural (I don't mean one quarter space, like \, in LaTeX, rather a full space).

On the other hand, Cburnett believes that (taken from his talk page):

I'm vehemently opposed to having to make an article work around bugs or unexpected behavior (see discussion above to see what I mean [there Cburnett argues that one should put one category and language link per line, even if that causes some extra space at the bottom]). I did get my browser to wrap periods to the next line with equations (images really). However, I don't readily see this as a WP issue but rather a browser issue. Either way, whatever is decided on the wikiproject page I'll go with. Just can't promise I'll always remember. :) Cburnett 04:04, 19 Mar 2005 (UTC)

I wonder what everybody else thinks. Comments would really be much appreciated. Thank you. Oleg Alexandrov 17:21, 20 Mar 2005 (UTC)

Another point to go for after </math> is like with the new grammar bot. Rending the period in the tags means a bot might see the period if HTML rendered or might not if PNG rendered. It makes for an inconsistency even if the period is placed consistently. If placed external to the tags then it will always be there. And, no intention of insulting here, you have to be ****extremely**** pedantic to worry about a browser wrapping a period. :) Cburnett 18:32, 20 Mar 2005 (UTC)
About the bot thing. The bot does the queries based on the wiki source, not the final html, so will have no problems sticking its nose in math formulas. Oleg Alexandrov 02:48, 21 Mar 2005 (UTC)
The grammar bot (I forget the exact user name, perhaps User:GrammarBot) ignores math tags because of the commas. If you're going to require a bot to parse math tags then you've just added more complexity to keep a period from wrapping. Cburnett 03:26, 21 Mar 2005 (UTC)
I think so far GrammarBot was very sucessfully messing inside of formulas. Maybe it will be a new feature that it will not do that anymore. Now, about your concern. Let me tell you that the bot I wrote to put periods at the end of formulas semiautomatically had to deal with issues similar but worse than that (there is lots of variabitity to how people type formulas). Besides, the GrammarBot has nothing to do in or around a math formula anyway, since after the period (or comma) in an aligned formula one goes to a new line. Either way, I think our concern for bots should probably be the last thing to worry about. Oleg Alexandrov 03:59, 21 Mar 2005 (UTC)
If the bot is to detect sentences without a period then it'll have to parse inside and around formulas. Really, though, if you want to worry about wrapping periods then I'll worry about bots. Both are equally pedantic and both are concerned about a mundane detail instead of actually writing or editting articles. Cburnett 04:05, 21 Mar 2005 (UTC)
If you are not pedantic yourself, and if you don't care if there is a period at the end of formula to start with, why are you so pedantic about where the period is? :) I think you are right. We are wasting time here. You can do what you love most, editing articles, and I will continue with the issue which has been concerning me me for at least one month, that is, proper punctuation of math articles. How's that? :) Oleg Alexandrov 04:18, 21 Mar 2005 (UTC)
Try rereading what I wrote. Notably, the second sentence. Cburnett 04:27, 21 Mar 2005 (UTC)
You are right again. I focused on your very provocative third sentence. So let us not imply that what the other is doing is irrelevant, because then you should not take part in this discussion to start with.
On your second sentence, I do not buy the bot argument. We will probably not agree on this. Let us see what others have to say. Oleg Alexandrov 04:32, 21 Mar 2005 (UTC)
When did I call it irrelevant? Cburnett 05:06, 21 Mar 2005 (UTC)
My fault. I overreacted. I read it (the third sentence) to mean that some people spend their time in an useful way writing good articles, and some other people have nothing better to do than argue about pedantic issues ultimately of little importance. But I had time to think about it, and agree that what you said can be interpreted as saying that there are two kind of issues, one of writing articles and the other one of taking care of the fine details. So, sorry!
Either way, I think better arguments can be found than the bot thing, and it seems that ultimately nobody really cares about this issue except us two and cesarb. Let us see if more developments happen. Oleg Alexandrov 05:12, 21 Mar 2005 (UTC)
I would put it after </math>, because it's not part of the formula. Only things that are part of the formula should be inside the tags. As a bonus, it gives some extra spacing before the period.
I found an easy way to prevent breaking: the <nobr> element. Since it's not supported by mediawiki (and in fact not part of the HTML standard), I created a template nobr using the standard way of doing a <nobr> (and in fact, the way used by Mozilla's default HTML stylesheet).
Here's how to use it:
I disagree with Cburnett about it being pedantic; with some large formulas (I've seen formulas that take more than half of my screen, and I use a huge resolution), it's quite easy when using lower resolutions to end up with a period by itself in the next line.
A more extreme example (you can comment it out after the discussion is over, it will cause scrollbars to appear):
cesarb 19:40, 20 Mar 2005 (UTC)
Oh, and by the way, if this is too verbose, it would be easy to create a template to simplify it, containing something like:
cesarb 19:57, 20 Mar 2005 (UTC)

Vote for after. We should not compromise logic. There should be better workarounds. Isn't there a Unicode character specifically to glue parts together? – Sebastian 05:33, 2005 Mar 21 (UTC)

If you are thinking of the non-breaking space, it won't work (it would only work if it was replacing a space character; there is no space character). The nobr template I made works. --cesarb 10:01, 21 Mar 2005 (UTC)
The template cesarb suggests would work. However, I don't see it getting widely adopted (it is hard enough to convince people to care about putting that period to start with).
I agree with Sebastian about the logic thing. When I type LaTeX papers I don't like the period to be inside of the formula. However, on Wikipedia we have just three options (a) put the period after /math and not worry about misalignment, as this is a browser bug — this is what Cburnett says (b) put the period after, but do some kind of quick fix like a template, which cesarb suggests and (c) put the period inside, which is kind of a hack too.
Dealing with numbered formulas, like

does not make things easier. Here, probably the period should go before (1) rather than after (with some spacing between the formula and the period in some situations — if necessary — but probably not in this case).

So, no perfect solutions, but I would still think the third option is better than the first two. Oleg Alexandrov 12:50, 21 Mar 2005 (UTC)
I don't see the problem with the numbered formulas. The number is not part of the formula. In fact, it usually is written in the same font as the text. Sometimes you even find a name for the equation before the number - so it should really be outside of the . Moreover, it is not uncommon to put the punctuation after the the number, which I also regard as more logical. Example: Eddington, The Constants of Nature in The World of Mathematics, Vol. 2.Sebastian 09:45, 2005 Mar 22 (UTC)
Well, it is not standard to put the period after the equation number. (Actually, LaTeX does not even give you a choice.)
It seems that people are pretty split about this (2 for period inside, 3 for period outside), and there were not as many people involved in this as could have been.
So, I guess a solution would need to wait until the browser and display technology will advance — do you hear that Cburnett? — like switching to MathML where hopefully this will not be an issue.
However, there was broad agreement that sentences with formulas at the end must have a period. Unless I hear any objections, in several days I will resume putting the periods. I will put them inside the math tags, as again, it seems to me that this is the least problematic way. But, I will not attempt to convert the formulas where the period is there, but outside the math tag, as I had originally planned.
If, again, I hear no objections, I am aware that there could be disagreements about individual instances, where one might feel there needs to be some spacing between the period and the formula, or that a period does more harm than good in that instance. Since my work will be semi-automatic anyway, just feel free to revert or change those cases. In most situations however, I do not expect these to be an issue.
Anyway, let us see how it goes. Oleg Alexandrov 21:18, 23 Mar 2005 (UTC)
Objection. The (admittedly narrow) majority voted for outside, and it's technically feasible with the stub mentioned above; so there's no reason to put them inside. I also disagree with using LaTeX's inability as an argument. Our criterium should be what we deem most straightforward logically. — Sebastian 22:09, 2005 Mar 23 (UTC)

Vanity references?

I wanted to alert everyone to some edits I've just noticed. Take a look at IP's contribution list: [4]. Notice that all of the edits were adding links to abstracts or papers by someone named " J.Foukzon". They were not, as far as I could tell, particularly relevant to the articles (I could be wrong). I'm wondering if someone might be engaging in something which could be called "vanity references". This could be a particularly insidious form of vandalism. One that could be difficult to deal with, since it can be hard to verify that a reference is really relevant. Paul August 20:37, Mar 20, 2005 (UTC)

Certainly references like both the ones on Path integral formulation (now only visible in the history) are unnecessary and, while broadly 'relevant' to the subject at hand, at best add nothing to the article and at worst distract from more suitable references. The Foukzon references in that article are in fact conference papers that have not yet been presented (appearing July 2005); sheesh! Well spotted, Paul. Ben Cairns 22:06, 20 Mar 2005 (UTC).
I would say, delete without further fuss. Oleg Alexandrov 22:16, 20 Mar 2005 (UTC)

Structure of math articles

I have seen some mathematics articles that suffer from too narrow a perspective, like laplace operator, which completely ignored generalization to forms and still ignores a discription in terms of covariant derivatives so it would apply to all tensors. The laplace article is still very far from decent since it does not say anything usefull about the (general) Laplace operator, but that's another issue.

Also I have seen some mathematics articles which are now physicist territory, like Noether's theorem and Lagrangian. I think that a good article should start at it's highest level and then explain how lower levels are special cases of it. These lower levels may then also have their own page if necessary. And if something has application to physics or anything else, these should then be treated. Sometimes people say that this is an encyclopedia as a reason for excluding certain information that is considered too specialised/difficult. I don't see their point. Any comments? MarSch 16:07, 26 Mar 2005 (UTC)

I agree that we should discuss generalizations. However, I strongly disagree with your statement that "a good article should start at its highest level". Instead, we should "start simple, then move toward more abstract and general statements as the article proceeds" (quote from Wikipedia:WikiProject Mathematics). This has the advantage that we don't scare away people that are not interested in the generalizations; people that do want to read about the most general case will understand (and skip) the lower levels. For instance, I think the article on the Laplace operator should start with the definition
But by all means, proceed to treat the definition .
The split mathematics/physics should be handled on a case-by-case basis. I definitely agree with you for Noether's theorem and I would be very happy if somebody will tackle this article. For another view, read Wikipedia:Village pump (miscellaneous)#where are the chemists?, from which I quote: "Turning to physics, I often find articles which appear to have been hijacked by mathematicians, causing them to loose insight into _physics_ principles." -- Jitse Niesen 22:31, 26 Mar 2005 (UTC)

Ugh. I completely disagree with the form of the recent edits to Laplace operator by User:MarSch. As a geometer, I like the fact that the full abstract definition has been added, but it should appear later in the article, after a simpler high-school/college-level definition.
Please keep in mind why people come to Wikipedia in the first place: to learn something new, to refresh thier memory, to look up a forgotten formula. There is nothing worse that one can do to a reader than to overwhelm them with abstractions they don't understand. For example, any chemist, who may have had a few semesters of quantum, would be lost in this article as it currently stands. Ditto for any structural engineer, or electronics engineer. These are people who would use wikipedia, and frankly, they outnumber the geometers by a hundred to one. The article should cater to that level of understanding first, and then, only later, turn to the more abstract definitions. As an example of where this works, see the definition of the discrete laplace operator, which appears at the end of the article, not at the beginining. linas 02:02, 27 Mar 2005 (UTC)
Agree with Jitse and Linas. Most people will not appreciate seeing things in their higher perspective upfront. Besides, bottom-up, from particular to general, is the natural way of learning things. Oleg Alexandrov 02:44, 27 Mar 2005 (UTC)

Thanks for your comments. My above viewpoints reflect my feeling of a lack of modern math content. I agree that by making the article more difficult I have, hopefully temporarily, made Laplace operator worse, because there wasn't and still isn't any informal stuff. I have been reading the project pages on structure of mathematics articles and searching for a good example article, and I have not been able to find what a good article should look like. I have given it some thought and I think what is most lacking from, as far as have seen, all articles is a good motivation at the beginning of the article (everything before the TOC) of why that article is interesting to read. After that should come a good informal treatment with few or no formulas and still after that should come the formal treatment. After this section should come some applications. What i was trying to say earlier was about the formal section, it should be as general as the article title warrants and then reduce to some special cases. At the moment Laplace operator has only a formal section, which is why it is very difficult to understand right now. Writing good motivational and informal stuff is probably one of the most difficult things one can do, because they require a very clear understanding of a subject. MarSch 11:34, 28 Mar 2005 (UTC)

I think we will all agree that math articles here need more motivation, more applications, more connections with other articles and relevant real world examples. This is mentioned at Wikipedia:How to write a Wikipedia article on Mathematics (maybe not in such uncertain terms as MarSch would like). However, I think no amount of motivation or explanation is going to make Laplace operator a good article, if instead of starting with the Laplacian as a sum of partial derivatives one goes right to the Laplacian on manifolds, a huge number of formulas, and a very general abstract treatment. I think that some kind of consensus was reached that going from most general to the particular is not the way to go. Oleg Alexandrov 18:29, 28 Mar 2005 (UTC)
The ideal on Wikipedia is to give a 'concentric' treatment: brief lead paragraph, then more details, then further details for the reader who needs them ... and even link to other pages when the extra details become very long. This is actually the opposite of the Bourbaki idea that you start with the supposedly 'correct' general definition. Now, we as mathematicians have some problems doing it that way; but in the end it is better to give an accessible treatment. Charles Matthews 15:00, 1 Apr 2005 (UTC)
This discussion and the one on Laplace operator have changed my mind. All parts of the article should start simple and end very very hard ;) -MarSch 14:34, 4 Apr 2005 (UTC)

encouraging references for formulas

formulas and constants are especially vulnerable to malicious vandalism. adding a square root, changing a single digit, etc. how do we fight it? two possible treatments:

  • encourage references for every formula
  • encourage people who know the formulas and numbers well to watch the pages

see Fourier_transform#Continuous_Fourier_transform for an example where I included an image from another site as a reference in comments after an anon removed an erroneous sqrt sign.

- Omegatron 16:01, Mar 28, 2005 (UTC)

the square root probably went over the 2pi? This is just a problem of definition. Do you want the Fourier transform and it's inverse to "look the same". It is a convention. You should probably mention that two versions exist.
In general I guess we gotta watch our formulas. If we use them to derive a few simple properties or prove something then mistakes will be spotted sooner.-MarSch 17:26, 28 Mar 2005 (UTC)
You're right. It was just over the 2pi. But I've seen other small changes here and there that were incorrect. - Omegatron 17:35, Mar 28, 2005 (UTC)
It's tricky to reference formulae as we often want to fit in with the style of related articles within Wikipedia, meaning we might use a "paraphrased" formula rather than one directly from a paper or book. (As a trivial example, we might write "sum nx" rather than "n sum x".) Just as for any other topic, that means those that know the subject need to watch the pages and check for subtle changes. --stochata 21:27, 28 Mar 2005 (UTC)
I agree in principle with Omegatron. I've added a section to Wikipedia:WikiProject_Mathematics/Proofs specifically deal with this type of issue. linas 03:58, 3 Apr 2005 (UTC)

Apr 2005 – May 2005

Educational trampoline

I'd like to propose the creation of a new WP math policy (and category) concerning articles that are of particular educational value. I have in mind articles, such as Pi and Torus, which, if properly written and edited, could be accessible to pre-teens and still be interesting and fun for experts. Articles in this category would provide a portal for bright kids or teens (or even college freshmen) to launch into sophisticated math topics. For example: torus: when I was 9 years old, my teacher wrote formulas for a sphere, cylinder and torus on the blackboard: this is clearly a topic accessible to youth. Yet the article continues on to mention Lie groups and cohomology (and links to modular forms), which are advanced undergrad or grad-student topics. If this article is properly structured, it could provide a fine entrance to many fantastic topics in math.

The suggestion here is then only to create and apply some special editorial guidelines to articles in this class, and to create a special category so that educators could easily find them and thus suggest them for brighter students. If there is general agreement, I'd like to make this an official WikiProject Mathematics policy. linas 03:49, 3 Apr 2005 (UTC)

I'm very confused. Why does the inclusion of Lie groups and cohomology, esp. later in the article, make the elementary discussion any less accessible?? If an article is not accessible enough for the audience you talk about, then what is needed is more attention to the elementary presentation, not a deletion or excision of the advanced material. Of course, if the advanced material starts to overwhelm the entire article, a split may be called for. But not including things about the advanced properties is a disservice to those who are looking for this. The point is, if the elementary treatment is first, then the audience you are talking about it will read it, go as far as they can, and then turn away when they're overwhelmed by terminology or abstraction. And the people looking for an abstract treatment will be mature enough to recognize the various levels presented and navigate around the article. If we're worried about scaring people off simply by presenting an advanced treatment in addition to a wonderful elementary treatment, then we're underestimating the readers. "Knowing where you starting to get lost" is sort of a skill itself that will become more and more important as the information age goes on. And besides, why should we guess where a reader's "level" stops? They might read the elementary part, come back a year or two later and read more, and a year or two after that and read the advanced. The article could become an old friend rather than an enemy. And for me, at least, reading about things I don't quite yet understand often leads me to investigate further and I sometimes end up learning quite a bit I didn't know before. Maybe there are precocious undergrads (or evne high school students) who are really interested what the heck a Lie group is, or what cohomology is. It's not Why close these opportunities off? Revolver 14:36, 12 Apr 2005 (UTC)
It would be very nice to have such articles. I suggest you choose one article to convert/improve as an experiment. Hopefully this could lead to improved structure of all our articles. -MarSch 14:25, 4 Apr 2005 (UTC)
It's Wikibooks that is the designated place for textbook development. The suggestion seems to be along the lines rather of the material in the kind of popularising, accessible book that really does have a chance of interesting readers without much background. Still, it does sound more like a Wikibook, to me. Charles Matthews 14:52, 4 Apr 2005 (UTC)
I don't believe in wikibooks. Yet. I like linas vision of the future of WP. -MarSch 13:51, 7 Apr 2005 (UTC)
Providing an introduction for math articles (or wikipedia articles in general) is a good thing. It makes the articles accessible to a wide range of people. But writing an article which can be used for studying a certain topic is an entirely different matter. Wikipedia is an encyclopedia as such is primarily used for looking up information. The structure of the articles should reflect this and present the information in an accessible and neutral way. A textbook on the other hand should be structured according to pedagogical principles. These principles vary from author to author as does the selection of material. MathMartin 15:25, 7 Apr 2005 (UTC)
I agree with MathMartin. We need to keep the encyclopedic style. So, several styles (described below) which were mentioned in places in the discussions on these pages are not quite encyclopedic. They are:
(a) Writing very concise articles containing just formulas and listing theorems (a la Abramowitz and Stegun)
(b) Writing things in a top-down approach.
(c) Making articles with pedagogical bent.
(d) For that matter, putting proofs in the articles, unless they are useful to the statement of the theorem or are otherwise instructive. Oleg Alexandrov 17:05, 7 Apr 2005 (UTC)
If you want encyclopedic then that is the Bourbaki way and thinigs should be top-down. Nobody wants this. Instead everybody wants our articles to be easily understandable. I believe linas proposed to make some articles _extremely understandable_ and thus accessible to children. In addition he proposed to make these articles more interesting by providing connections with other subjects. Don't we want interesting understandable articles? Also proofs are always usefull, and if someone is not interested than they can be skipped, but they provide a way of checking that a result is properly stated and should always be included. MarSch 12:49, 12 Apr 2005 (UTC)
These generalisations are always only indicative. It is pretty clear that some proofs should be included, others not, and so on. Some articles, particularly on recent work (from the past 40 years, maybe) are likely just to be surveys. Something no one has said yet, I think: accessible often will mean visual, so one direction in which to concentrate efforts is to add many more diagrams, not more words (waffle). Charles Matthews 12:52, 12 Apr 2005 (UTC)

I think Revolver got my meaning completely reversed; I wholly agree with him. In fact, I intended to suggest that an article like "torus" could safely include more links to various complex topics. I also wanted to suggest, that the progression from simple to complex be made a tad less challenging, so that the article becomes slightly easier to follow. However, one must stop short of writing a book. Borwein wrote a book about Pi, but if you look at his book, much of the material in it is already covered by various wikipedia articles. For example, Borwein's book on Pi has a chapter on modular forms or something like that (not sure); whatever that connection is, via Ramanujan's series, it could be spelled out in a a few sentences, followed by a wiki link. Similarly, a torus is a great example of a simple Teichmuller space. We don't have to write the book; but adding the words to establish the link would be good.

Very few articles in Wikipedia have the opportunity to bridge from simple to complex. Pi, Torus and modular arithmetic are a few that come to mind. Most of the rest of the articles cover topics that are either too advanced, or have no natural ties to a wide range of topics. This is why I wanted a special category for the few articles that have this magic property of being broadly relevant. linas 15:27, 13 Apr 2005 (UTC)

Disagree with some of this. As far as I know a torus isn't a Teichmuller space. You can relate π to modular forms if you want; you can relate it to Buffon's needle too - I'd be surprised if there was anything you couldn't relate it to, in mathematics. I'm not here to sell anything specific, and I think Wikipedia policies make it better just to build up 'core material' in a steady way. Charles Matthews 18:40, 19 Apr 2005 (UTC)

Error in rendering of html math

''L<sup>p</sup>'' gives Lp (rendered as <i>L<sup>p</sup></i>)

''L''<sup>''p''</sup> gives Lp (rendered as <i>L</i><sup><i>p</i></sup>)

Apparently, for a lot of users, these expressions are identical but I see something close to Lp for the second (where the p is slightly smaller font). I use the konqueror browser version 3.2.1. My question is: is this a bug in the wiki software or in my browser?

''L''<sup>p</sup> renders the way I would expect: Lp Jan van Male 18:45, 12 Apr 2005 (UTC)

They look the same in Firefox. Ibelievethisis the correctbehaviorfornested tags.
(Although the wiki software seems to remove nested tags! Interesting. Because it assumes they are mistakes? What if you need to print xfs? Oh. That works. But nested supers do not: xfs) hehehe - Omegatron 19:12, Apr 12, 2005 (UTC)
I use Konqueror, they look the same to me. (and both look good). Your choice of default fonts, maybe? linas 15:31, 13 Apr 2005 (UTC)
Using different fonts does not help here. I'll see whether the konqueror bug database turns up anything usefull. Jan van Male 16:22, 13 Apr 2005 (UTC)
Yes. Nested sup/sub tags are broken in MediaWiki!! :( Vote for bug #599 and maybe it will get some attention and be fixed. Dysprosia 03:02, 20 May 2005 (UTC)

Articles needing diagrams

Is there a page listing mathematics articles which are in need of diagrams? If not, we should create one somewhere. There are plenty of articles which could be listed. I am handy at doing commutative diagrams and don't mind doing them but I'm completely inept when it comes to anything requiring artistic talent. I'd like a place where I could put up some requests and handle others. -- Fropuff 17:02, 2005 Apr 14 (UTC)

Well, there already is Wikipedia:Requested_images#Mathematics. - Omegatron 19:20, Apr 14, 2005 (UTC)
There are presently no requests in there. Maybe I'll try populating it and see if I get any turnaround. -- Fropuff 22:04, 2005 Apr 21 (UTC)
I think a separate page for mathematics-related articles would be a good idea. Fredrik | talk 22:08, 21 Apr 2005 (UTC)

Template:MacTutor Biography — what about Template:MathGenealogy like it?

I have noticed a recently created Template:MacTutor Biography — looks like a cool idea. I've found 26 articles on people linking into the Mathematics Genealogy Project database, and thought about creating a template to link to it, similar to the MacTutor one. Does anybody have any objections against me going ahead and doing it? BACbKA 18:54, 16 Apr 2005 (UTC)

Update: I have done the above. Please use the template when linking to the mathematical genealogy project database entries; also you're welcome to improve the template text. BACbKA 12:50, 17 Apr 2005 (UTC)

Plutonium recalculations

Can someone please redo the calculations involving the half life of Pu on pages RTG and Voyager program to reflect the proper half life of 87.7 years instead of 85 year current value? thx.--Deglr6328 01:55, 17 Apr 2005 (UTC)

Have done this on RTG. -MarSch 12:49, 19 Apr 2005 (UTC)

Several proposals to modify the List of mathematical topics

The List of mathematical topics is a very useful resource, as from there one can track the recent changes to all the listed math articles (try Recent changes in mathematics articles, A-C). Its only weakness is that quite a lot of math articles are missing from there (in addition to the 3537 articles listed at the moment, there are at least 2000 not listed — and this is a very conservative estimate, the actual number could be as high as 3000 or more).

Now that we have the math categories, and most math articles are categorized, one idea is to add to List of mathematical topics by harvesting the articles listed in the math categories. I would be willing to do that, especially that I already have written some scripts which do most of the work.

One issue would be how to sort the articles, this is discussed at Talk:List of mathematical topics, and seems to be a tractable problem, even if one needs to sort the mathematicians by last name.

That was the first proposal. I wonder what people think. Now, the second proposal. Charles Matthews suggested (see again Talk:List of mathematical topics, at the bottom), to remove the mathematicians listed there altogether, as they have their own list, List of mathematicians. So, some feedback on this is also needed.

Now, to the third proposal, closely related to the above. You see, adding lots of new articles will make the lists quite big, and even now some are big (for example, List of mathematical topics (A-C) is 58KB, with almost all contents being links). This causes issues when the server is slow, and when updating with new entries (it happened in the past that the lists actually got corrupted because of that). It can also be hard to check the diffs if lots of changes happen. So, the proposal is to further split the lists, with each letter getting its own article.

Backward compatibility can be ensured by using a template-like thing. If we have the articles List of mathematical topics (A), List of mathematical topics (B), List of mathematical topics (C), one can insert in List of mathematical topics (A-C) the lines:

{{:List of mathematical topics (A)}}

{{:List of mathematical topics (B)}}

{{:List of mathematical topics (C)}}

and the appearance of this list would be as before, and can be also edited as before. The link Recent changes in mathematics articles, A-C will still work (I tried these).

So, I wonder what people think of these proposals. Note that they are related, but a decision on one of them need not affect the decision on the other ones. Oleg Alexandrov 02:33, 19 Apr 2005 (UTC)

All the above seems fine to me. Paul August 02:57, Apr 19, 2005 (UTC)
Having heard no objections, I will proceed. I will also create a List of mathematics categories, which I will populate as I move along. I will try to work on this this weekend, or either way do it by next Wednesday. Oleg Alexandrov 21:40, 21 Apr 2005 (UTC)
All three proposals sound good to me. The template trick is rather nifty; I had no idea that worked. -- Fropuff 22:02, 2005 Apr 21 (UTC)

Scanned math monographs of Polish mathematicians

Today after following an external link from Lebesgue-Stieltjes_integration I found the following gem [5]. On this page journals and monographs from Polish mathematicians can be downloaded free of charge. (for example the complete french translation of Stefan Banachs Théorie des opérations linéaires.) If nobody objects I would like to start a section in Wikipedia:WikiProject Mathematics with a list of webpages where older mathematical monographs and journal articles can be accessed. I know there are simialar projects in France and Germany going on. I think it is fantastic that many important math journal articles can now be found online making it possible to link them directly from the relevant wikipedia articles.MathMartin 21:24, 19 Apr 2005 (UTC)

Gathering together our conventions

The new page Wikipedia:WikiProject Mathematics/Conventions is to collect up our current set of working conventions. Please add any more to it, and use its talk page to discuss the adequacy or otherwise of those conventions. Charles Matthews 11:13, 23 Apr 2005 (UTC)

Renaming the List of lists of mathematical topics ?

There is a discussion at Talk:List of lists of mathematical topics#Renaming this list. I wonder what you think about those suggestions, and which, if any is preferred. Thanks. Oleg Alexandrov 00:31, 24 Apr 2005 (UTC)


Someone has listed Pearson distribution for deletion:

For some reason this is picking up a few delete votes, and I don't understand why. It's not my field but I know this is a fairly popular distribution nowadays. Any help with cleanup, keep votes, etc, welcome. --Tony Sidaway|Talk 02:18, 28 Apr 2005 (UTC)

"Things to do" section?

I'm thinking about adding a "Things To Do" section to the project page, some thing like:

Things to do

Looking for something to do? There are several places on Wikipedia where mathematics related requests, suggestions and tasks have been collected together:

What Where
Suggest or edit a mathematics article needing attention Pages needing attention: Mathematics
Suggest or edit a statistics article needing attention Pages needing attention: Statistics
Suggest or write a mathematics article Requested articles: Mathematics
Expand a mathematics "stub" Mathematics stubs
Suggest or edit a redirect which could have its own article Redirects with possibilities: Mathematics
Help move PlanetMath content onto Wikipeia PlanetMath Exchange

Any comments? Paul August 18:26, Apr 28, 2005 (UTC)

Sounds fine with me. Some of these links already show up at the bottom of Wikipedia :WikiProject Mathematics. The PlanetMath Exchange link shows up somewhere higher on the same page. To integrate all of these nicely would be good. Oleg Alexandrov 18:41, 28 Apr 2005 (UTC)

Ok I've added the above to the project page. Paul August 22:03, May 3, 2005 (UTC)

Template:Calculus -- is that needed?

Topics in Calculus

Fundamental theorem | Function | Limits of functions | Continuity | Calculus with polynomials | Mean value theorem


Product rule | Quotient rule | Chain rule | Implicit differentiation | Taylor's theorem | Related rates


Integration by substitution | Integration by parts | Integration by trigonometric substitution | Solids of revolution | Integration by disks | Integration by cylindrical shells | Improper integrals | Lists of integrals

Vector Calculus

Vector | Vector field | Matrix | Partial Derivative | Directional Derivative | Gradient | Flux | Divergence | Divergence Theorem | Del | Curl | Green's Theorem | Stokes' Theorem | Path Integral

Tensor Calculus

Tensor | Tensor field | Tensor product | Exterior power | Exterior Derivative | Covariant derivative | Manifold

I just wonder, are things like Template:Calculus so useful? I put it to the right just for illustration.

(Note: the template refered to above is now at Template:Calculus2 the first template displayed to the right is the "old" template, the "new" template, now at Template:Calculus is displayed below. Paul August 02:19, May 10, 2005 (UTC))

To me, as I followed its evolution, it looks like an ever growing monster of links, popping up in many places. Besides, it is very long and wide, taking up lots of room even on a 19" monitor with high resolution. Also, I thought the category system should take care of linking articles to each other.

I would suggest this template be eliminated, or otherwise be trimmed to the true calculus, which is integrals and derivatives on the real line, no vector calculus, tensor calculus, and what not. Opinions? Oleg Alexandrov 23:08, 29 Apr 2005 (UTC)

I do not like the template. The scope is too broad and it takes up too much space in the article. So either trim down radically or delete entirely. MathMartin 10:03, 30 Apr 2005 (UTC)

My attitude: I have removed it in a number of places. I think it might actually be useful to some readers; but it doesn't need to be on every calculus article. Charles Matthews 12:49, 30 Apr 2005 (UTC)
I agree. It takes up too much space. I think the vector and tensor calculus stuff should go. Perhaps moved to their own templates. Paul August 13:23, Apr 30, 2005 (UTC)

I have an idea. We could put Vector Calculus and Tensor Calculus as topics under Topics in Calculus, get rid of all the subtopics that were under those two headings, and then make the overall sidebar narrower. I think that might sufficiently trim it down. Sholtar 21:25, May 3, 2005 (UTC)

I've made a template to show what it would look like the way I suggested. It's located at Template:Calculus2 (now at Template:Calculus see note above Paul August 02:19, May 10, 2005 (UTC)). If you compare it to the former one, I think this one is much more reasonable in size and would be adequate as far as links are concerned as well. What do you all think? Sholtar 22:21, May 3, 2005 (UTC)
Looks good, thanks! But I can't promise that at some later moment I won't feel like trimming more the template. :) By the way, what do you think of creating a Category:Vector calculus? That will put the related topics in the same box. Same might work for the tensors. Oleg Alexandrov 22:25, 3 May 2005 (UTC)
Hmm... yeah, having a Vector calculus category and a Tensor calculus category would probably help. Should they have sidebars, or just categories? Sholtar 22:46, May 3, 2005 (UTC)
I thought the very purpose of categories is to group similar subjects together. And my own humble opinion is that one does a better job that way than by using templates (sidebars, that is). One day, when I get to it, I will carve out Category:Vector calculus as a subcategory in Category:Multivariate calculus. Oleg Alexandrov 22:59, 3 May 2005 (UTC)
This is true, but templates do make for somewhat easier navigation between topics within a category. Anyways, unless there's any disagreement, I'm going to put the slimmer template in to replace the current one and back the current one up in Calculus2 if it's needed for future reference. Sholtar 23:10, May 3, 2005 (UTC)

I suggest limiting the use of templates to articles most likely to be read by high-school and college students, and then only on articles that are widely and broadly taught. They have pedagogical value for a student trying to master the material. Thus, the fat template might actually be a lot more useful than the thin template. However, it should be used on only a few pages. linas 17:02, 14 May 2005 (UTC)

Now on VfD: Evaluation operator

The mathematical article evaluation operator is now on VfD; see Wikipedia:Votes for deletion/Evaluation operator. It is claimed to be original research. Unfortunately, it is now too late for me to investigate it. Related articles are multiscale calculus and theta calculus. -- Jitse Niesen 00:39, 10 May 2005 (UTC)

I should have added that I spotted this while listing an another article, namely John Gabriel's Nth root algorithm. Its VfD entry is at Wikipedia:Votes for deletion/John Gabriel's Nth root algorithm. -- Jitse Niesen 08:15, 10 May 2005 (UTC)

Reminds me of this group: eucalculus, differation, atromeroptics. These seem to be personal definitions/original research, and should presumably go to VfD. Charles Matthews 08:47, 10 May 2005 (UTC)
The evaluation operator surfaced on the german Wikipedia, was discussed at de:Portal Mathematik and put to VfD there. After assuring myself that only the original author uses this term but was rather busy creating a net of articles here, I put it on VfD here. --Pjacobi 09:58, 2005 May 10 (UTC)

I listed eucalculus on VfD, after verifying that I could not find a peer-reviewed article about it. The VfD entry is Wikipedia:Votes for deletion/Eucalculus. -- Jitse Niesen 22:57, 12 May 2005 (UTC)

Discussion on german Wikipedia seems to indicate, that Theta calculus and Multiscale calculus, at least in their current form, are original research by User:Dirnstorfer. Opinions? VfD? --Pjacobi 15:26, 2005 May 13 (UTC)

Evaluation operator has now been deleted, and the other two articles are listed on VfD; their entries are at Wikipedia:Votes for deletion/Theta calculus and Wikipedia:Votes for deletion/Multiscale calculus. -- Jitse Niesen 22:24, 17 May 2005 (UTC)

Major fields of mathemtics

I've added an 'Major fields of Mathematics' template to the Matematics Categories page. It's based on the classification used in The Mathematical Atlas. Any comments or suggestions? --R.Koot 13:38, 10 May 2005 (UTC)

The template in question is at Template:Mathematics-footer.
Now, first of all, the style here is not too use that many capitals. That is, one writes "Linear algebra" instead of "Linear Algebra", and "In mathematics" instead of "In Mathematics".
About the template. I myself do not think it is a good idea. There is already a Areas of mathematics article, having good information.
I would like to note that the very purpose of categories is to group related subjects together. As such, navigational templates should not be used that much, they just become link farms showing up all over the place.
This is my own personal thinking, and I am somewhat biased against templates for the reason above. I wonder what others think. Oleg Alexandrov 20:36, 10 May 2005 (UTC)
On this one, I'm going to have to agree with Oleg Alexandrov. I like templates personally, but they have to be used with moderation. I just don't think this one is neccessary. Sholtar 23:23, May 10, 2005 (UTC)
I agree with Oleg. I am against using a template for this category. Note: I believe that templates are useful and nice in certain pedagogical settings, see debate on the calculus template above. However, a template is inapporpriate for this cat. linas 17:30, 14 May 2005 (UTC)

To be honest I think that this template shouldn't be neccessary, I had two (good) reasons for creating one. The first is that is is also done in the Category:Technology and more importantly, the current categorisations of articles is quite a mess, which makes it very difficult for the non-mathematicain to quickly get an overview of mathematics major fields. --R.Koot 00:32, 11 May 2005 (UTC)

The Category:Mathematics is not a mess. Math has many more facets than just subject areas. The categories reflect this. Oleg Alexandrov 00:47, 11 May 2005 (UTC)
We should probably come to a consensus about whether or not to do this in all categories, but just because someone did it for technology doesn't seem to be a feasible reason to do it for mathematics. I think unless a consensus is reached about the subject, default to whether or not it's neccessary. This one I just don't think is neccessary, especially because there's an article about the major fields. Sholtar 05:23, May 11, 2005 (UTC)

I agree that mathematics is much richer than it's fields. Therefore the template is biased, but adding more links to it make it lose it's purpose so I suggest the following:

  • Remove the template.
  • Put all the articles that are categorized direcly under mathematics in a subcategory, except for the Mathematics article itself, and maybe a select group of introductory articles like Areas of mathematics (articles that help navigate you quickly and would propably be found in a real encycolpedia).
  • Rename a lot of the categories from Mathematical foo to Foo_(mathematics), this would make the index more readable and is the prefered Wikipedia style, I believe.
  • Design a good categorization system and make people aware of it. A suggestion
   Logic             Computer Science                   Literature
   Set Theory        Signal Processing                      Journals
   Arithmetics           Digital Signal Processing      History
   Combinatorics         Transforms                     Recreational Mathemtics
   Number Theory         Wavelets                           Games
   Algebra           ...                                ...

Now you could either put all the categories in the three columns together under Category:Mathematics or put them in their own subcategory (Pure Mathematics, Applied Mathematics), resulting in a rather tiny index, whcih would probalbly be my preference, but I think this might be a bit too controversial? --R.Koot 10:52, 11 May 2005 (UTC)

(This was written before I saw R.Koot's comment above.) At the moment, we have several ways to navigate through the articles:
  • Wikilinks. This works well, but requires the user to read a lot of text to find the link he is interested in.
  • Categories. They are very useful, but in my opinion not very user-friendly. I actually agree that Category:Mathematics is a bit of a mess; part of the problem is that the list is sorted alphabetically, another part is the lists mixes very different kinds of subcategories, like Cellular Automata (a small subfield), Geometry (a big subfield), Formula needs explanation (a category meant for editors) and Theorems.
  • Lists like list of linear algebra topics. They provide more flexibility (one can sort articles as one wants, introduce subheadings, annotations), but the experience shows that these lists are difficult to maintain.
  • Navigational boxes. Again, I think these can be useful, but they take up space (especially when implemented as sidebars instead of footers) and they tend to grow out of control.
Unfortunately, none of these is perfect. I believe Charles Matthews has written a whole piece comparing these navigational aids, but I cannot find it anymore. But it would be good to build some sort of consensus on which to use where. -- Jitse Niesen 11:10, 11 May 2005 (UTC)
The point about our existing systems of lists and categories is that they have grown up organically, in line with the articles. They are not an imposed, top-down categorisation. I support strongly the idea of doing it this way. After all, where do top-down lists come from? They are basically a bureaucratic idea, and not very compatible with wiki self-organising principles. What we need are a few structures to support the existing system. For example, a 'guide' page outlining the category system, and some project page on which to discuss areas where the coverage remains weak. Charles Matthews 08:55, 13 May 2005 (UTC)
This is a very good point. MathMartin 16:44, 14 May 2005 (UTC)

I see that R.Koot went ahead and performed the edits anyway, despite the discussion. I disagree with a number of the edits. About a month ago, Category:mathematics had approx 300 articles. I categorized almost all of them, leaving behind about 30 articles that gave a flavour of mathematics, that dealt with topics that were broadly applicable to all branches of mathematics, or that were inter-disciplinary, giving a sense of the relation of mathematics to broader society. While not perfect, the remaining lone articles in combination with the list of categories, gave a pretty good overview of what math is about. I am rather distressed that the collection of individual articles were shorn out of the category (I started reverting last night, I plan to continue when my spirits increase). linas 17:46, 14 May 2005 (UTC)

As to the 65 subcategories of mathematics, its certain that this list could be cleaned up a bit and shortened; but I'm sure I'd shit the proverbial brick if it was not done correctly. linas 17:46, 14 May 2005 (UTC)

vote for MarSch's adminization

Please visit Wikipedia:Requests for adminship and vote on my application. I want to do some edits on protected pages, but I have too few edits yet to get enough anonymous support, so since you guys know me a little better I'm hoping that my edit count will be less of an issue. So please take a look. -MarSch 14:43, 13 May 2005 (UTC)

Hoaxer is back

Kimberton's Poppages Theorem, now deleted, was the Bryleigh (Cayley/Newbirth) hoaxer again. Not possible to do a long-term block on the IPs used. Everyone please look out for hoaxes. Charles Matthews 14:08, 14 May 2005 (UTC)

Is there a way of monitoring what articles are added to (or removed from) a category? I'm wondering how you discovered the existance of the above page. (No doubt, you're aware of my recent bout of categorization and thus interest in such things.) linas 17:54, 14 May 2005 (UTC)
It's possible to monitor added articles, but not removed articles; see m:Help:Category#Detection_of_additions_to_a_category. Daniel 18:26, 14 May 2005 (UTC)

mathbf or boldsymbol?

Typically, bold font is used for vectors, as in . Note that does not have the desired effect. I think it would be better to use \boldsymbol as in (Igny 23:52, 15 May 2005 (UTC))

Well, we'll use whatever works. We can use mathbf, and when it doesn't work, we can use boldsymbol. Observe also that does not show up the same as , which may be undesirable. Dysprosia 23:49, 15 May 2005 (UTC)
I didn't know about boldsymbol, but I like it. Use whatever is more appropriate. -MarSch 11:43, 16 May 2005 (UTC)
Vector valued variables should be written bold but not italic so you should use \mathbf not \boldsymbol --R.Koot 00:37, 17 May 2005 (UTC)
Agree with R.Koot. Oleg Alexandrov 01:18, 17 May 2005 (UTC)

Problem with the "what links here" feature, affecting the recent changes to list of mathematical topics

If you check what links to the article Osculating circle, one can see that it linked from the List of mathematical topics (O). However, it does not look as if it is linked from list of mathematical topics (M-O), which is very strange, because if you click on that page you will certainly see the article listed.

On the other hand, if you look at what links to Alan Turing, you will see a link from List of mathematical topics (S-U), which is wrong, as if you visit List of mathematical topics (S-U) you will not see Alan Turing listed there. I removed this article from there a long while ago (since it shows up in list of mathematicians).

As such, the "what links here" feature does not show links which exist, and does show links which do not exist. This affects the "rececent changes" from list of mathematical topics. I find this very strange. Anybody having any ideas with what is going on? Oleg Alexandrov 19:15, 18 May 2005 (UTC)

I seem to remember that there are some bugs with What links here when combined with templates. I think you should look in the list with wikimedia bugs for details, or wait and hope that somebody gives you a more precise answer. Jitse Niesen 21:06, 18 May 2005 (UTC)
I've been seeing stuff like this in more than Mathematics, but I can't really help you out in knowing what the problem is. It's probably just some kind of bug with the overall feature, as Jitse said. Sholtar 04:13, 2005 May 19 (UTC)
I went to List of mathematical topics (J-L) and just inserted a comment and saved the thing. Miraculously, the "what links here" feature worked just fine afterwards! The moral I think is that every once in a while applying a dummy edit will refresh the database, and quirks as above -- where linked articles did not show as linked and unlinked articles showed as linked -- will not show up. Oleg Alexandrov 19:39, 21 May 2005 (UTC)

Move of "Mathematical beauty" to "Aesthetics in mathematics", comments?

(Discussion moved to Talk:Mathematical beauty#Move of "Mathematical beauty" to "Aesthetics in mathematics", comments?. — Paul August 20:00, May 27, 2005 (UTC))

Covariant, contravariant, etc.

Here is some discussion from my talk page. -- The Anome 14:57, May 20, 2005 (UTC)

User:Pdn wrote:

The entry Contravariant has a notice: "This article should be merged into covariant transformation. If you disagree with this request, please discuss it on the article's talk page." I very much disagree. I wrote something on the discussion page but the notice is still there, so here I go.

The term covariant has two very different meanings. In relativity theory (and probably differential geometry) it refers to the invariance of a quantity (generally a measurable one) when coordinates are changed, including changes among relatively moving reference frames. For example, the velocity of light is covariant, and the rest mass of an object can be determined in a way that does not depend on coordinate system or reference frame, i.e. a covariant way. But covariant also refers, unfortunately, to certain components of a vector or tensor that do usually change very much when the coordinates change. The simplest example is the vector from one point to another in ordinary three dimensional geometry. In the usual Euclidean metric, the numerical values of the contravariant and covariant versions of the vector are identical. If we perform a coordinate transformation doubling all the coordinates, (x',y',z') = (2x,2y,2z) then all the contravariant coordinates double but the covariant ones are cut in half. The distance, which depends only on the products of the coordinate differences (contravariant times covariant) (summed, and then the square root taken) does not change. It is covariant, but the covariant coordinate increments were all cut in half. The transformation is a covariant one, but does not preserve the covariant components. The invariance of the distance relates to the discussion of "covariant transformation" while the discussion of the changes in individual coordinate values, contravariant vs covariant, belongs in "contravariant". Thus, the notice suggesting merge should be removed. If you want to match "contravariant" with something, then you should create a page "covariant component" as opposed to "covariant transformation." Else you could rename "contravariant" as "Contravariant and covariant components" and I will port some of this discussion in there. These very concepts are rather passé now, at least in relativity theory, as the use of differential forms is supplanting old fashioned tensor analysis, but some folks still use tensors for fluid and continuum mechanics [6], rheology [7], mechanical vibration, crystal optics [8] and other fields not so suitable for the fancier newer maths so the entries should not be dropped. Simple tensor analysis is helpful when a cause (force, mechanical stress, polarized optical beam, e.g.) produce an effect imperfectly aligned with it. Such usages do not lend themselves as much to exterior differential form analysis so there's no reason to toss old-fashioned tensor analysis. Pdn 13:48, 19 May 2005 (UTC)

[...time passes...]

Dear Anome (sorry to put this as a trailer on some vandalism , but I do not know how to create new messages without appending to old.) I'm afraid that the two usages of "covariant" are so very different that your concept of parallel disambiguation pages won't fly. I have never heard of a "contravariant transformation", though you could ask a person more expert than I in differential geometry or differential forms. As I explained, "covariant components" and "contravariant components" are two faces, so to speak, of the same thing. The second one, in the case of the differentials of coordinates (hope I restricted my remark to that case) is an integrable quantity, a thing many people do not realise. Thus, if one totals the contravariant component of "dx" around some closed curve one gets the change in x, a property not generally shared with the covariant component of dx. I do not know how "covariant" came to be used for vector components, but I do not see it as related to the invariance under transformations. The devil of it is that we can't just change "covariant transformation" to "transformation with invariants" for many reasons, including wide usage probably started by Einstein. You could make up a disambiguation page for "covariant" pointing to "covariant transformation" on the one hand and "covariant tensor components" on the other. Unfortunately you cannot just use names like "covariant tensor" and/or "contravariant tensor" because these are two faces of one item. So you would have to work with "covariant tensor components" and make up a page like the existing one for "contravariant" for that case, so you could change "contravariant" to "contravariant tensor components." Actually, now that I think of it you could rename "contravariant" as "contravariant and covariant tensor components" and I'd be glad to fill in the "covariant" portion - you can leave a stub. Then the disambiguation page would fork between "covariant transformation" and "contravariant and covariant tensor components."

I think we probably need to discuss this at the Wikipedia:WikiProject Mathematics I agree with you about the covariant and contravariant components of tensors; tensors seem to be a particularly tricky subject here for some reason. The term "contravariant transform" seems to have been used: see Google for a few examples of what seem at least at first sight to be valid uses. The other terms really need some thought; you've certainly convinced me that a simple merge/redirect alone will not do the job. To that end, I'm copying your recent comments and this reply into the Wikipedia talk:WikiProject Mathematics page. -- The Anome 14:51, May 20, 2005 (UTC)
Some confusion here. Differential forms, which are always contravariant, can only 'replace' tensors that are already contravariant and antisymmetric with respect to interchange of indices. The "components" terminology causes more confusion than anything else in this area, I think. In the presense of a metric you can indeed 'raise and lower indices', so have the option of taking the components of the variance you want; but that is very much not the basic situation with tensors. Charles Matthews 15:14, 20 May 2005 (UTC)
When physicists say covariant, they mean tensorial as far as I know. Since tensors exist without reference to any coordinate system they don't transform.
This is a fine mess we have here. I think the article about covariant transformations is really about coordinate transformations. Then the components of tensors transform co(ntra)variantly as per their nature. Perhaps we should merge the lot with tensor or tensor field. You can only take covariant components and contravariant components of a (co)vector when you have a metric.--MarSch 15:34, 20 May 2005 (UTC)

I am afraid you maths guys are taking the definitions and discussion too far away from what is used by engineers and the more pedestrian of physicists. I have taught relativity using differential forms, but not for a while and had forgotten that part about their always being contravariant. Engineers would be floored by trying to use differential forms and I am not even sure they are useful for elasticity, fluid mechanics in Newtonian theory, birefringent optics, and so on. In all the cases normally used by physicists and engineers, you do have a metric. So the math is getting far afield by discussing cases with and without metric. There are some anomalous theories in physics where the metric is affected by another field (e.g. Brans-Dicke theory and other "conformal" theories,) and it may be that branes can make the usual usage of a metric muddled (path dependent) but you are getting so far from what can be used in most colleges and in university courses in physics or engineering up through second year graduate school, that I am getting queasy. In relativity, we distinguish general covariance and covariance under the special theory of relativity. In the latter case, measurable quantities have to be invariant to the Lorentz transformation (in the most general sense, including translations and rotations, as well as [constant] velocity differences, but not to time-varying rotation). In the former, the measurables must be locally invariant to change to systems in relative acceleration, including time-varying rotation. While coordinate changes are not measurables in the strictest sense, distances are. By "the strictest sense" I mean that a reliable measuring tape or clock does not measure a coordinate, but it measures the distance, including the metric. I will stop here or the debate entries will become too long. Anyway, to physicists "covariant" does not mean "tensorial" in my opinion, it means invariant to certain coordinate and reference frame changes as I described above. Pdn 14:42, 21 May 2005 (UTC)

I'm confused by the confusion. A covariant transformation is the thing that changes the coordinate system on a covariant tensor component on a (mixed) tensor. Ditto for contra. Mass and speed of light are invariant and not covariant. The people who study branes and Brans-Dicke know differential geometry inside-out and upside-down, so I'm not worried about them. The above seems to be implying that there is something else out there, not yet documented in WP, that is called a "covariant transformation" ?? what is that thing? linas 00:19, 22 May 2005 (UTC)

You are absolutely right - sorry - there is no such thing as a covariant or contravariant transformation. If one wants to make up separate names for the operations on covariant and contravariant components, one could use these names, but that would obscure the fact that (when there is a metric) both kinds of components are just different aspects of one thing, the tensor. So I would think that the two items could be combined into one about how to transform tensors, in component form. And also you are right that I should have used "invariant" for scalars that remain fixed in transformation. I just now referred (way) back to Peter Bergmann's book "Introduction to the Theory of Relativity" (Prentice-Hall, 1942) and my memory is returning: equations can be covariant under certain kinds of transformation; the transformation is not the covariant thing. When the equation (such as ) is preserved under coordinate transformations it is covariant. I also agree, and I am glad you agree, that people doing advanced work such as branes and conformal theories do not need any help from Wikipedia; that is why I wanted to steer away from cases where there is no metric, which were referred to by MarSch on May 20. So I suppose we need entries for tensors and their transfromation rules, covariant and contravariant components, and covariance of equations - the exact titles are not clear to me. In regards to the previous comment (also by MarSch): ":::When physicists say covariant, they mean tensorial as far as I know. Since tensors exist without reference to any coordinate system they don't transform." I agree in part - the tensor is "there" and we just see different views of it when we take components in different systems, but we need to retain some of what was taught to engineers, physicists and maybe even some differential geometers, who can't easily be weaned from components. I am now probably going to cease writing here because there is, indeed, so much confusion over covariant, covariant transformation and contravariant, and you mathematicians should be the ones to settle it. I just hope you leave something useable by scientists and engineers who do not want to learn more advanced mathematics than they have to, but want to use tensors.Pdn 03:12, 22 May 2005 (UTC)

Yes I agree, three articles on essentially one topic is too much. All three, covariant, covariant transformation and contravariant should be merged. Yes, the expression "covariant transformation" is a poor choice of language, and the new article should be purged of this expression. Oleg is right, there are times when a metric doesn't exist, or the metric is not invertible, but these cases should be treated in distinct articles (non-invertible metrics occur in subriemannian geometry; a special language exists for this case.). The component notation is just fine for the merge article. (The metric-less and componenent-free case is already dealt with in the pullback/pushforward articles.) Not sure what MarSch is going on about with this component-less thing; I'd like to see him write a computer program that graphs pictures of tensor quantities without using components ;-). If an equation is invariant under a change of coordinates, one calls that equation invariant in modern terminology, not covariant. I guess some folks might still use the term "covariant" in this case, but suspect its anachronistic. I'm not planning on doing any merging myself. linas 06:40, 22 May 2005 (UTC)
Oh, and I do see one point of confusion: the "transformation" of tensors under changes of vector basis is related to, but not at all the same thing as the "transformation" of tensor fields under change of coordinates. Unfortunately, these two distinct concepts often do get conflated. linas 06:48, 22 May 2005 (UTC)

I do not see any difference between a tensor and a tensor field, unless the former is a very special case, being defined at only one point, and therefore of little use. I do not consider terms like "covariant" (for invariance of an equation under special-relativistic transformations) and "generally covariant" for invariance under more arbitrary transformations in GR (I say "more arbitrary" because I want to keep the light cones etc preserved) to be out of date. That's what Einstein used so it is worth preserving; otherwise people need to ask the mathematicians who changed the definition what Einstein meant. This kind of thing is often tried by well-intended people who like, nevertheless, to play "follow-the-leader." One outstanding case was the late (I believe) Parry Moon of MIT. He wrote the article on illumination in the 1956 Encyclopedia Brittannica, wherein he tried to replace ordinary concepts like brightness, illumination, luminous flux, the lumen etc by a new breed of terms such as "pharosage","lamprosity" (sounds like something that invaded the Great Lakes, killing many gamefish), "blondel," "stilb" and "apostilb." The terms have not stuck very well but can be found here and there. Moon and collaborators (such as Domina Eberle Spencer and Euclid Eberle Moon) wrote many bizarre papers. Early on, Moon and Spencer claimed, in J.Opt.Soc.Am. 43,635(1953), that according to relativity, light from distant galaxies could reach Earth in a few hours or days. This was picked up by young-earth creationists, and stil is, but it is nonsense. More recently, the indomitable trio published items supporting a ballistic theory of light in Physics Essays, and for the latest see this: [9]. So be careful about renaming things like the covariance of an equation. It may be a sign of impending senility. OK, nowadays a janitor is a "building engineer" and an overweight person is "gravitationally challenged," but that's harmless, while to side-track people who want to understand the writings of Einstein, Minkowski, Weyl, Pauli, and many capable if not illustrious successors by requiring them to consult Wikipedia talk pages to find out that the "covariance" of an equation is now called "invariance" is uncool. The forgoing was not a filibuster and I am not a filibusterer [10]. One final point: Somebody (I believe he was named Kretschmer) once pointed out that you can make anything into a tensor by defining it in one system and transforming it to any other by tensor transformation rules. So, reflecting on that, we see that "covariance" of a physical quantity or scientific equation means that the same measurement process used to measure it in one system will measure the transformed version of in (transformed using tensor rules) in another system. For example. E^2-B^2 where E is electric field and B magnetic is covariant. E-B is not, but if you measure E-B in one frame and then transform it to other frames by brute force with tensor rules you can claim that it is covariant or invariant etc. So "general covariance" has more to it - that the physical content is carried over to new frames - not just math.Pdn 05:09, 23 May 2005 (UTC)

What I don't like about merging into covariant and contravariant is that those are adjectives, so the article is about a descriptor instead of a thing. As a physicist I came across covariant transformation long before covariant, but that's because we usually define co(ntra)variant vectors by how they transform. If they're going to be merged into one article, how about at least something like covariant tensor. But personally this differential geometry talk is above my head, and I'm just pulling for them ending up somewhere that makes sense to physicists, too. --Laura Scudder | Talk 22:41, 26 May 2005 (UTC)

Since this issue is being clouded by various points-of-view, I think we need to talk structure and organisation first. Nouns are better than adjectives, as Laura implies: so we need to treat covariance and contravariance in some central place. I suggest making covariance and contravariance the 'top level', most general article, and hang things like tensor field (all those indices) off it. Charles Matthews 09:17, 27 May 2005 (UTC)

Talk:Squaring the circle

Perhaps my fellow math-nerds should look at Talk:Squaring the circle. I have taken the position that the article is about the legitimate mathematical problem of squaring the circle and the proof, published in 1882, that it is impossible; that although it should mention crackpots who continue working on squaring the circle, nonetheless that that topic is at most tangential (to the circle?)Pdn 15:10, 21 May 2005 (UTC). As nearly as I can tell, a Wikipedian named Sebastian Helm is saying that squaring the circle is a topic invented by crackpots rather than a legitimate mathematical problem. He seems very angry at my assertion to the contrary, which he called "BS". Michael Hardy 04:06, 21 May 2005 (UTC)

I am sorry about the misunderstanding. What i called BS was your "example of a conspiracy of space aliens". I never said that "squaring the circle is a topic invented by crackpots". And i got angry because you keep putting words in my mouth which i never said or meant (on three counts including this one). You don't even have to assume good faith, if you just stick with the facts. — Sebastian (talk) 16:30, 2005 May 21 (UTC)
I think all of this started with Sebastian putting Squaring the circle in Category:Pathological science, which is kind of undeserved. Oleg Alexandrov 17:45, 21 May 2005 (UTC)

I agree with Michael and Oleg in questioning the appropriateness of the category "pathological science", for this article. In fact, I think that "pathological science" is a problematical name for a category. The description given here seems to imply as much, and Sebastian seems to agree, quoting from here: "I don't like the name "Category:Pathological science", either, but this was the closest i could find." A good category name should be self-explanatory, which this one is not. It should not require a paragraph to define, and then still be not quite clear (to me at least). Having said that, there is some merit to what this category is trying to describe. And it does have some relationship to this article. And there are other mathematical topics which might share this relationship, for example other impossible contructions like angle trisection (do people still try to do this?).

As to the somewhat unpleasant discussion between Michael and Sebastian, I think there has been some misunderstanding going on. I do not see that Sebastian said or implied that "squaring the circle is a topic invented by crackpots rather than a legitimate mathematical problem". Nor do I think he meant to imply that by assigning the article to the category "pathological science", although I can see why Michael might have thought so. I think everyone agrees that "squaring the circle" was a legitimate problem considered by serious and reputable mathematicians, prior to the proof that it is impossible. However, that people nevertheless are still trying to square the circle, is an interesting phenomenon, which is deserving of some thought and discussion, and perhaps even a category. Paul August 21:08, May 21, 2005 (UTC)

Yes, I agree. This is exactly what i meant! Thanks for getting back on topic! Possible names include:

  • pointless scientific efforts
  • misguided scientific endeavours
  • research which flies in the face of facts

Sebastian (talk) 22:10, 2005 May 21 (UTC)

Squaring the circle is not the right article for a more-than-tangential mention of mathematical crackpots. Certainly a separate article could treat that. Michael Hardy 01:24, 22 May 2005 (UTC)

Micheal, I think the request is to come up with a catchy category name that says "this topic is a legit topic that tends to attract crackpots"; not just math but in general. free energy and casimir effect spring to mind. linas 06:56, 22 May 2005 (UTC)
What exactly is the motivation behind creating a category bringing together subjects 'attracting crackpots'? Surely not to attract crackpots more effectively. It seems kind of unencyclopedic to give these things too much attention. Charles Matthews 20:51, 27 May 2005 (UTC)

Perhaps category:pseudoscience is the category which Sebastian is looking for. Although I don't think it would be appropriate for Squaring the circle. And pseudomathematics could be the right place for a more lengthy description of the phenomenon represented by the continued attempts to square the circle. Paul August 21:19, May 27, 2005 (UTC)

I'll say first of all that it's clear all this resolves around the aggressively named category "Pathological science". Let me draw a more modern parallel.

In complexity theory, a classical result is that the class NL, and indeed the entire log-space hierarchy, collapses to NL — that is, NL is closed under complement. I've read papers predating this discovery by the most eminent of researchers, still alive today, that claimed that most researchers reasonably believed that the log-space hierarchy did not collapse, and they based some of their results on this. A similar thing happened with the discovery that SL is closed under complement, widely believed to be false not so long ago and now trivial as a consequence of L=SL.

The short of it is, very smart and very reasonable people have good reasons to believe that things that are false. Neither they nor the goals they pursue are "pathological" or even "misguided"; rather, they are reasonable actions based on available knowledge.

Finally, one more example: I can't remember the name, but one of the founders of noneuclidean geometry actually believed that Euclid's parallel postulate could be derived from the remaining axioms — in other words, his aim was to disprove the existence of any alternate geometry. He assumed that the axiom was false for purposes of contradiction, going on to write a large book deriving many results from noneuclidean geometry, eventually uncovering a "contradiction" which was actually an error and proclaiming the theorem proved. Was he a crackpot? No. Was his effort pointless? Not at all! He didn't achieve the unattainable goal he set, but he discovered a lot of useful things in the process. You don't tell a kid they'll never be an astronaut.

So what's a good category? I vote for Category: Disproven conjectures.

Deco 09:44, 28 May 2005 (UTC)

Possible crackpot pages

Seems that User:Laurascudder has unearthed a cluster of physics pages of highly dubious content. I'm not sure what to do with them. I'd suggest VfD except that I don't quite know that process.

and possibly also

although this last one almost does make sense.

As a whole, these pages seem to be filed with errors, ommisions, indecipherable formulas, a mixture of trite and deep statements, notation pulled from many different areas of physics and mashed together in highly non-standard, incoherent ways. My gut impression is that most of this stuff is dubious "original research" by an out-of-work Soviet nuclear technician who has a strong grounding in physics, but was unable to master quantum field theory as it is taught today. So what's the WP process for stuff like this? linas 16:39, 22 May 2005 (UTC)

Linas, I recommend heading over to Wikipedia:Votes for deletion and going to the bottom of the page, there are instructions there for listing on VfD. Even if these pages end up being worth keeping, it's still a good thing to know. Sholtar 17:11, May 22, 2005 (UTC)

These are all created by the same guy - Rudchenko (no user page, so link shows all contributions to date). Maxwells nonlinear equations looks especially suspect to me... (I always understoof Maxwell's equations are the whole and the entirity of non-quantum electromagnetism). I will try contacing people I know to get some definate answers. Tompw 17:07, 22 May 2005 (UTC)

Gluonic vacuum field should also be looked at. It seems to belong to the same cluster of articles. Paul August 03:28, May 23, 2005 (UTC)
Well, it seems they have gone to VfD anyway, which is a process hard to stop once it is started. Rather than theorising about the author, I think it is important to focus on what we know about the content. Which is indeed about an alternate line of field theory, to standard QFT. There is a key passage on one of the pages, which I will cite when I find it. Charles Matthews 10:01, 23 May 2005 (UTC)
Right, the place to begin is certainly w-field, with its reference to an approach to field theory attributed to Gustav Mie. One approach is to assume that all essentially all these pages are working out consequences of that idea. Original research they may be - I wouldn't know enough about this corner of theoretical physics to know. I don't think they should be deleted simply because the approach is different from standard QED. Charles Matthews 10:08, 23 May 2005 (UTC)
Hi Charles, I'm the one who VfD'ed it. The reason for this is not so much that they're non-standard (you should know by now that I have a weakness for non-standard things), but rather 1) they're pretending to be something they aren't: one could formulate a non-linear electrodynamics, but this isn't what's being done here. 2) They're filled with deductive errors. Sure, the pionic field is pseudo-scalar, (it changes sign under parity), but to argue that this means that the associated (non-relativistic) potential is purely imaginary is bizarre/wrong; the (non-relativistic) Hamiltonian wouldn't be hermitian, which is wrong. I suppose one could try to build up some quantum theory with non-Hermitian pseudo-Hamiltonians, but you'd have to lay oodles of groundwork first, and it might not work out in the end. 3) The same formulas show up in gluonic vacuum field and quantization of pionic field. That's wrong. If it had been called pionic vacuum field, that might have flown, but gluons are non-abelian, they belong to the adjoint rep of su(3); they're very different than pions, which would be a singlet of su(3). One musn't write an article about gluon-anything without saying su(3) at least once. 4) Multiple instances of the usage of the non-relativistically covariant Schroedinger equation, followed by remarks such as "we can use the Klien-Gordon equation". 5) article on coherence condition: one can't write down a kinetic term that way, at least not without oodles of justification. The 'coherence condition', a purported variational minimization of the Lagrangian, is missing a few terms. The presentation turns incoherent shortly thereafter; the variation δ s should not be thought of as "non-fixed numbers".
As far as I'm concerned, this stuff is a word salad of formulas, the likes of which is common in the underworld of flying saucer theory. Sure, one can build alternative theories, but one needs to lay a groundwork, define terms and the like. One mustn't say "D^2s=0" without first explaining what "D" is. And next, one must point out in the preface that these are "alternative theories", rather than pretending that Maxwell had invented some kind of non-linear equations (and thereby implying legitimacy). That's why I VfD'ed them; these articles are beyond repair. linas 14:49, 23 May 2005 (UTC)
FWIW, here's why I expound so confidently: my PhD thesis was on the Casimir effect inside of protons/neutrons, so I know a lot about the quantum vacuum state and QCD in general. This quark vacuum was coupled to a topological soliton made out pions. That's how I got my grounding in math. As to pions ... somewhere (misplaced) I have a copy of the "Pion-Nucleon Interaction", signed by the authors, Andy Jackson (my advisor) and Gerry Brown, (his advisor). Gerry, unwelcome in the US, spent the McCarthy years running around Europe setting up nuclear research centers; one might say things like RHIC and the neutron star equation of state are his legacy. You can find a few of my lame publications from that era on e.g. "Justifying the Chiral Bag", cited by 21, hot damn!linas 15:15, 23 May 2005 (UTC)
One more quickie remark: The standard formulation of a non-linear version of Maxwell's equations is known as Yang-Mills theory, which these days is understood to be a principal bundle with fiber SU(N). Rudchenko's attempts seem to be an effort to use SU(2), given the appearence of the cross-product. Until he explains how it differs from the 'standard' SU(2) formulation, its just bunk. linas 16:51, 23 May 2005 (UTC)
The articles are of such low quality they would have to be rewritten anyway. Further, the only person that seems to know anything about it Rudchenko stopped contributing several months ago. And last but not least I could not find any papers on the subjects (except for w-field and nonlinear magnetic field) meaning this will never be verifyalbe. So I'm in favor of a delete. --R.Koot 12:45, 23 May 2005 (UTC)
Rudchenko is still contributing but is using anon IPs, see:, and probably: and Paul August 16:52, May 23, 2005 (UTC)
I'm confused. From and he tweaked some formulas, which you wouldn't do if this was a hoax. While he has been creating a link farm and given some very strange replies on talk pages from (If your known similar calculation please give sign here. Rudchenko.)? --R.Koot 18:27, 23 May 2005 (UTC)
inetnum: -
descr: Donetsk Regional General Scientific Library
country: UA (Ukraine)
inetnum: -
country: UA
address: Scientific & Technological Centre FTICOM
inetnum: -
descr: Dial-up pools and interface addresses. FARLEP-TELECOM-HOLDING, a subprovider of Farlep-Internet in Donetsk, Ukraine
country: UA
I think it is more likely that these articles are original research than hoaxes. Paul August 19:07, May 23, 2005 (UTC)

Extended Yukawa Potential, Yukawa Potential. Maybe this is of some use to anyone? --R.Koot 13:04, 23 May 2005 (UTC)
Be aware that google and even is blissfully unaware of most modern physics and math. Dead-tree media still underpins the dominant publishing paradigm. linas 16:07, 23 May 2005 (UTC)

Revert to an old version of manifold

(Moved to Talk:Manifold. Oleg Alexandrov 16:59, 27 May 2005 (UTC))

Use of this page

It is better, I think, if discussions on page content are left on the talk pages of the articles. It is perfectly fine if, in the case of an article of basic importance to mathematicians, an invitation to participate is made on this page. I really don't think long discussion threads on specific content issues are correctly placed here. Charles Matthews 10:11, 27 May 2005 (UTC)

Right. Sorry, I did not think it will go that far. Not again. Oleg Alexandrov 15:33, 27 May 2005 (UTC)

I agree with Charles. For obvious reasons, page-specific discussions, usually best occur on that page's talk page. I think there is a tendency to raise page-specific issues here, in order to reach a potentially wider audience, which I must say I do find useful, both as one who wants to "reach", as well as be reached. But as Charles implied, that can, to some extent at least, be accomplished by posting a notice (perhaps together with an excerpt of an ongoing discussion) here, with a request that further discussion occur there. In any event, any page-specific discussions which do occur here, should, at some point, be copied or moved to the associated talk page, so as to preserve a more complete historical record there. To that end, unless anyone objects, I will move the above section "Move of "Mathematical beauty" to "Aesthetics in mathematics", comments?", which I initiated, to Talk:Mathematical beauty. Paul August 16:32, May 27, 2005 (UTC)

By the way, I also wanted to say that I quite value this project's active and vibrant discussions. The more we do it, the better we should get at it. A project needs a certain critical mass of activity to remain viable. This is a great project and it has a great group of participants, and if it takes an occasional "off-topic" discussion to keep it active or to assure ourselves that some of us are still alive and kicking, then it is worth it ;-) (Perhaps, from time to time, we should take attendance!) However, as this page's only archivist, Charles may have mixed feelings about the volume of discussion ;-) — so I pledge to help out with that task in the future and also in accord with my earlier comment, I volunteer to go through all of this page's archives, and copy any page-specific discussions to the appropriate talk page. Paul August 18:02, May 27, 2005 (UTC)

I think we should create a section on this page to note important discussions: obviously if big edits to mathematics, manifold and so on are being mooted, it is of general interest. Charles Matthews 18:07, 27 May 2005 (UTC)

Should there be a distinct math-related VfD page? Are VfD's common in math? At any rate, if any come up, I think announces should be posted at least here. linas 20:34, 27 May 2005 (UTC)
They are not so common. There have been a few 'crank' pages in the past. Mostly poor material can just be dealt with by redirecting. Also, it is not always clear when topics are technically wrong: who knows enough to be an expert in all branches of mathematics? So my policy is not to rush to VfD. Of course sometimes we need it. Charles Matthews 14:08, 30 May 2005 (UTC)

Two math pages set for deletion

Algebra I has been submitted for deletion, and I did the same thing today for Algebra II. They are about courses with the same name. I think does not look encyclopedic. But either way, here are the links:

Oleg Alexandrov 00:10, 30 May 2005 (UTC)

Might I direct your attention to Long-tail traffic as well. It has a VfD banner on it, but isn't on the list. At least one of the pictures seems to be scanned and the rest of the article gives that impression too. Reference [1] are lecture notes on ELEN5007 so this is probalby someone who put his paper on Wikipedia. --R.Koot 00:27, 30 May 2005 (UTC)
This article is part of a collection of articles, which are all part of a class project. They are being discussed here: Wikipedia:Deletion_policy/Teletraffic_Engineering. Paul August 01:45, May 30, 2005 (UTC)
Thanks, I missed that. Very strange though... --R.Koot 11:40, 30 May 2005 (UTC)

Vfd for space mixing theory

The page on space mixing theory seems to be unpublished work. I called for a vote for deletion. I hope this is the right forum for announcing that. If not, I apologize, and would really appreciate it if someone could point me to the right place to discuss deletion of unreal science. Bambaiah 10:39, May 30, 2005 (UTC)

Current active content discussion

Please edit this section to keep it up to date (major topics only)


for some of the more important content discussions now active in this WikiProject.

Nominated article


  • I nominate Lebesgue integral. Charles Matthews 08:17, 19 Feb 2004 (UTC)
    • Hello Charles. I do like the Lebesgue integral article, although it gets bogged down toward the end -- it seems like the discussion sections can be tightened up quite a bit. Comments? Wile E. Heresiarch 02:33, 8 Apr 2004 (UTC)
      • Always room for improvement. I chose it mainly because it touches all the major bases (motivation, some history, towards applications, picture, real content), so is quite a good template. Charles Matthews 06:31, 8 Apr 2004 (UTC)
  • I second the nomination for Lebesgue integral. I'll also nominate Bayes' theorem. Wile E. Heresiarch 02:33, 8 Apr 2004 (UTC)

Other articles I think are good in their ways are Boy's surface (graphics) and Nicholas Bourbaki (perspective and NPOV - I have worked on this one). Charles Matthews 09:19, 15 Jul 2004 (UTC)

Wikipedia:Classifications of mathematics topics

Seems this page was not updated in ages. And right on top is a suggestion to maybe delete. Indeed, what people think? We already have areas of mathematics, list of lists of mathematical topics, and list of mathematics categories. So, Wikipedia:Classifications of mathematics topics seems kind of reduntant. Or does this article have a purpose? Oleg Alexandrov 02:15, 22 May 2005 (UTC)

It proposes 2 categorizations one of which is original work and the second is included in areas of mathematics. Looking more closely this seems to be a talk page not an article? --R.Koot 15:24, 22 May 2005 (UTC)
What do you mean by original work? Oleg Alexandrov 16:01, 22 May 2005 (UTC)
I meant original research. --R.Koot

For now, I redirected Wikipedia:Classifications of mathematics topics to areas of mathematics, as the two aritcles have exactly the same purpose and the latter is more compete and better written. Both pages seem to be concerned with classifying the math on Wikipedia based on the American Mathematical Society's math subject classification, MSC2000.
Also, some content in Wikipedia:Classifications of mathematics topics makes me think that this page was either vandalized, or otherwise very sloppily edited.
By the way, I have a feel that areas of mathematics would need some work, but I don't know exactly what kind of work; it just feels somewhat unfinished. Any ideas on what to do with this page? Oleg Alexandrov 00:22, 2 Jun 2005 (UTC)

question about formatting of standard symbols

I am wondering whether there is any policy in this project about formatting for standard symbols like Q (the set of rational numbers). I sometimes see Q, sometimes Q, sometimes just Q, and on a few occasions the blackboard-bold version wrapped in <math> tags, i.e. . It's particularly jarring when these different versions appear in the same article (or sentence). I realise that if a single article uses both inline and <math> formats, then some inconsistency in appearance is unavoidable. Also I realise there's some conflict here between freedom and rules, with the concomitant effects on productivity. Still, I'm wondering if at least there is some consensus on the 'ideal' notation. Dmharvey 18:47, 31 May 2005 (UTC)

I think one needs to use either Q or . The first is preferable in inline formulas, as the second yields an image, which is undesirable, see Wikipedia:How to write a Wikipedia article on Mathematics. The second one is more preferrable in big formulas I think. Now, to use Q or plain Q for the rationals is not correct; it needs to be changed to one of the two if encountered.
Now, all this is my own opinion, but this seems to be the unwritten tradition. Oleg Alexandrov 01:46, 1 Jun 2005 (UTC)
I like to use both Q and . The blackboard bold should be reserved just for that: the blackboard. --MarSch 16:22, 1 Jun 2005 (UTC)
I think I agree that is a definite improvement on . Certainly in my regular work with LaTeX I stick to . Although usually it doesn't turn out so huge. And it could be argued that, in certain important respects, WP has a lot in common with the humble blackboard :-) If other people agree, perhaps the math(s) project needs somewhere for this kind of notational suggestion to belong. Does it belong under Wikipedia:WikiProject Mathematics/Conventions? Dmharvey 17:38, 1 Jun 2005 (UTC)

I always prefer using blackboard bold even in typeset work, as bold is used for too many things. This will always be a matter of opinion though; there will always be those who disagree. If more browsers supported it I would use ℚ in all my articles. For the time being I stick to Q and . -- Fropuff 18:25, 2005 Jun 1 (UTC)

I'd stick with blackboard bold, not only because I find it more pleasing aesthetically, be because it's a defacto standard. Maybe Wikipedia's policy of no original research should be extended to no original typesetting? --R.Koot 22:07, 1 Jun 2005 (UTC)
I personally like the LaTeX rendering, but I think it would be best to use only when it is not disruptive to the general flow. If an effort were made to set formulae aside from other text, perhaps making the statements first in "math lingo" and then restating what was just stated in TeX with standard English perhaps the entire issue could be resolved. Guardian of Light 5 July 2005 14:46 (UTC)

Jun 2005 – Jul 2005

Featured list nomination

Please see Wikipedia:Featured_list_candidates#Nominations.

I have nominated list of lists of mathematical topics (not to be confused with list of mathematical topics) to be a featured list. Please go to that nomination page to vote for or against it. Michael Hardy 01:22, 1 Jun 2005 (UTC)

PLEASE VOTE ON THIS at Wikipedia:Featured_list_candidates#Nominations. Some of the opinions expressed there are from persons who are naive in more ways than just mathematically. If you doubt this, see the accompanying discussion page at Wikipedia_talk:Featured_list_candidates#Nominations. Michael Hardy 00:59, 2 Jun 2005 (UTC)

why are the latex images so big anyway?

Again: why are the latex images so big anyway? I generally have my browser text set pretty large, yet the latexs still often look rather silly. Is there some kind of preference setting to adjust the rendering size? If not, is it technically possibly for somebody to do that? Dmharvey 17:45, 1 Jun 2005 (UTC)

In my work browser images look same size as text, while at home the images look much bigger. I don't know the reason. It might have to do with the screen resolution besides font sizes. So we again arrive at the time-established truth that one should not use latex images mixed with text, only on a separate line. That's why, back to the question of versus Q, one should use the latter when inline. Oleg Alexandrov 23:13, 1 Jun 2005 (UTC)
If only the MathML mode worked... --cesarb 23:32, 1 Jun 2005 (UTC)

OK, let's try something:

Consider the integral which is blah blah blah .....

(1) Look at this here equation: So there!

(2) Look at this here equation: AX2 + B = 0. So there!

(3) This renders all right: So ereht!

No, it does not. It looks exactly identical to (1) above; the characters are comically gigantic. Michael Hardy 01:44, 2 Jun 2005 (UTC)
FYI For me, (1),(2) and (3) are exactly the same size, and (2) and (3) visually look identical. I have a 1600x1280 monitor so use large fonts.linas 03:04, 3 Jun 2005 (UTC)

I generally use the format (2) rather than (1) for two reasons: the math notation in (1) is ridiculously too big, and it gets mis-aligned. Possibly this could be overcome by using a different browser or altering my preferences. I have long said that TeX looks good on Wikipedia when it is "displayed", but often looks terrible when embedded in lines of text. Note also: 1+2 does not look as good as 1 + 2; n + 2 is better than n + 2; and also better than n + 2. Michael Hardy 00:57, 2 Jun 2005 (UTC)

Number (3) render pretty good here (but this might look horrible if you have a larger/smaller font). This is actually quite an interesting question. What if rendering of math becomes unbroken in a future version of MediaWiki? You'd rather have the stuff between <math></math> than marked up using html. --R.Koot 01:21, 2 Jun 2005 (UTC)
See the link Archive4(TeX) at the very top of this page, discussing this in as much detail as one can get. Oleg Alexandrov 01:32, 2 Jun 2005 (UTC)

(3) looks exactly identical to (1) from my browser. Michael Hardy 01:43, 2 Jun 2005 (UTC)

Hmmm.. It looks SO good over here (Firefox/SuSE 9) that I thought it was a PNG, but it isn't it's HTML
<span class="texhtml"><i>A</i><i>X</i><sup>2</sup> + <i>B</i> = 0.</span>
The problem must be with the class="texhtml"? --R.Koot 01:56, 2 Jun 2005 (UTC)

Interestingly, the font in the TeX output is smaller on Wikicities. See example at [11]. Would this look better on Wikipedia? One problem is that it may be harder to read. - Fredrik | talk 01:49, 2 Jun 2005 (UTC)

Looks better inline but equations are MUCH harder too read. However is you could manually select the size (with two separate tage like <math> and <equation> for example it might work? --R.Koot 02:08, 2 Jun 2005 (UTC)
I was thinking the same thing. Also, clicking the image could show a very high resolution version in addition to the wrapped TeX code. Fredrik | talk 02:11, 2 Jun 2005 (UTC)

For me, the LaTeX images are slightly smaller than the surrounding text. But then, I'm using a 12pt font at 132DPI. Since most Windows boxes are at 96DPI (since a lot of Windows programs look weird if you try to change it), I can see how it can look huge. --cesarb 02:23, 2 Jun 2005 (UTC)

You will never get text in images and text not in images to mesh well for everyone. Saying it should be done one way or another because "it looks better" is just nonsense. It looks better to you on your screen, maybe; that says nothing about how it looks to everyone else. (BTW, I must interject at this point that the font used in the TeX images changed several months ago and I really preferred the old font!) The best solution, perhaps, would be to add a preference setting to scale LaTeX images to a (user-) specified relative size — for example, "80%" or "110%", etc. — so that each user could, if they cared, have the images scaled to match the size of the regular text in their own browser (I guess this would also have to include a vertical-shift option, as well, if that's possible to implement). The only problems I can see with this plan would be: (1) server load, since every (TeX) image would have to be tagged with height and width calculated using the user's scaling preference; and (2) readability since some browsers probably have terrible algorithms for scaling images. - dcljr (talk) 11:11, 2 Jun 2005 (UTC)

For me, (2) and (3) are identical. Only (1) looks bad. I think this is because I have selected "HTML if very simple or else PNG" in my prefs - it is not determined by my choice of browser. Lupin 12:32, 2 Jun 2005 (UTC)

(3) is the best, because I think using images for any kind of text is not a good thing to do.--Reubot 10:19, 5 Jun 2005 (UTC)

Thanks everyone for your comments and examples. I think I now understand a little better why this is such a complicated issue.

I have a question: how good is MathML at rendering inline equations (as opposed to displayed equations)? Does it handle things as well as LaTeX, like line wrapping?

Dmharvey Talk 12:56, 2 Jun 2005 (UTC)

I think the previous suggestion of a user-definable relative size attribute is quite nice. Note also that CSS (I don't know if this is true for "old style HTML attribs") allows for sizes given in "ex", e.i. the height of an "x" in the current font. maybe this could also used to fix the problem. But I also agree that (maybe unless you have a 1600x1200 screen, which is still rather exceptional - maybe wiki has statistics on screen resolution...) the images are always way too big w.r.t. the text, so a fix should definetly be provided. (Maybe also alternate style files (at worst through user prefs) could allow to cope with this issue.) MFH: Talk 22:32, 20 Jun 2005 (UTC)

tangent bundle and vector field

I would really like to know your opinion on what these articles should be about. Since the tangent bundle is basically the collection of vector fields, it would be useful to make it clear what info should go where. --MarSch 14:26, 2 Jun 2005 (UTC)

These articles certainly need a lot of work. For example, the vector field article should also have a more "introduction to several variables"-level version, with explicit formulae in terms of partial derivatives etc. There should be a version of tangent bundles in terms of submanifolds of euclidean space, as well as the more abstract version there currently. Dmharvey Talk 4:52, 2 Jun 2005 (UTC)
Tangent bundle should cover the holomorphic version, the version in algebraic geometry, too. There are also replacements (microbundles) to consider; and mappings on tangent bundles (not on vector fields - see the notorious push forward talk page discussion). Vector fields in plane regions is already an interesting area. So there seem to be reasons to have two pages. Charles Matthews 15:48, 2 Jun 2005 (UTC)

Wikipedia:Mathematics Collaboration of the Week

So what is happening there? The tag has been taken down from tensor, which was current. I don't see another nomination has been made. Charles Matthews 16:00, 2 Jun 2005 (UTC)


I'm sorry if this is the wrong place, but I wonder if there's copyright on proofs? Can I copy some proof from my lecture notes (in my own words)? Hugo 08:30, 2 Jun 2005 (UTC) (Moved from Wikipedia:WikiProject Mathematics/Proofs by Oleg Alexandrov)

Try asking at Wikipedia:Village_pump and then summarize the answers you get; I'd like to know myself. linas 01:07, 3 Jun 2005 (UTC)
(I'm not a lawyer) You will have to make a distinction between the structure of the proof and the text of the proof itself. The stucture is not copyrightable only patentable, and that is not possible because you can't patent mathematics. Whether the/a text is eligible for copyright depends on wheter or not is considered original. A proof consisting mainly of formulas, "let ... denote ...", and "from which we conclude", could hardly be considered orginal (and would be very hard to prove in court). However this might change if the proof contains original/creative explanations of the proof. Note that even rewiting the text in your own words is considered plagiarism (this might again be hard to prove in court but you or other Wikipedians might (should) have some moral problems with this). The safest would likely be to ask the author of the lecture notes if you could copy part of it to Wikipedia. --R.Koot 19:11, 3 Jun 2005 (UTC)
I would like to mention that if some theorem is missing a proof, that might be on purpose. Some of us (if not the majority) think that proofs should be a part of the article only if they ellucidate the article, and if they are not too hard. So, proofs for their own sake are not very encouraged. Discussion on this is under way at Wikipedia:WikiProject Mathematics/Proofs. Oleg Alexandrov 04:18, 4 Jun 2005 (UTC)
R.Koot, you are mistaken, it is possible (in the US) to patent pure mathematics when the math is the embodiment of some functional procedure or algorithm. Examples include the RSA encryption algorithm and the inversion procedures used in MRI scanners. So while in general you can't patent a proof there may be occasional exceptions if that proof is somehow a necessary component in the description of some otherwise patentable process. Such cases are likely to be very few and far between however. Dragons flight 01:15, Jun 23, 2005 (UTC)

Wikipedia:How to write a Wikipedia article on Mathematics

There are some interesting discussions going on at Wikipedia talk:How to write a Wikipedia article on Mathematics. I believe as many of us should be involved in that as possible, as that article is the main document defining how math is to be written. So, comments welcome. Oleg Alexandrov 22:25, 2 Jun 2005 (UTC)

Conjecture for deletion

According to newly created polygon sum conjecture article,

The Polygon sum conjecture is a geometric conjecture that states that the sum of the interior angles of a polygon are equal to 180(N-2), where N is equal to the number of sides that the polygon has.

I almost put it in Category:Conjectures, when I realized conjectures in elementary geometry do not happen that often... :)

Anyway, see Wikipedia:Votes for deletion/Polygon sum conjecture. Oleg Alexandrov 01:21, 3 Jun 2005 (UTC)

Also see Wikipedia:Votes for deletion/Roman letters used in mathematics Oleg Alexandrov 01:28, 3 Jun 2005 (UTC)

complex multiplication and e^(pi sqrt(163))

Dear all, I have added the fascinating fact concerning e^(pi sqrt(163)) to the article on complex multiplication. It doesn't really fit very well at the moment, but hopefully one day that will change. The only reason I mention this here is that I'm not sure if this formula appears anywhere else in WP, perhaps it is already stated elsewhere. Thanks peoples. Dmharvey Talk 01:32, 3 Jun 2005 (UTC)

I've added the equation to Pi, under "Numerical approximations of π". Fredrik | talk 05:00, 6 Jun 2005 (UTC)
There is currently an "explanation" with links to modular form and something else, which is quite frustrating because nothing is explained there. I would appreciate a more precise indication on "how", even if w/o details. MFH: Talk 12:58, 23 Jun 2005 (UTC)
I agree the explanation is drastically lacking in detail. I will try to do something about this at some point, but I don't promise anything soon. The problem is, to make this work sensibly would require an article on complex multiplication considerably more in-depth than the presently existing one. Dmharvey Talk 15:00, 23 Jun 2005 (UTC)

long-term of future of mathematics in wikipedia

(copied from the talk page of Charles. This is an interesting discussion, and I wonder what others would like to say Oleg Alexandrov 04:37, 3 Jun 2005 (UTC))

I am wondering what your opinion is of the possible long-term future of maths in wikipedia? In particular, do you think that wikipedia (or some other wiki-based medium) has the capacity to (eventually) become an authoritative source on well-understood material? I guess 'authoritative' and 'well-understood' are somewhat rubbery terms. For an arbitrary starting point, perhaps 'well-understood' might mean "material that has made it into book form by 2005", and 'authoritative' might mean that a professional mathematician might consider making WP their first port of call for learning material they are unfamiliar with. I appreciate your insight, you seem to have had a lot of experience on WP. Dmharvey 17:21, 30 May 2005 (UTC)

To try to sum up my take on this - mathematics is short of good survey articles, and not really short of textbooks, except for things that are quite recent. It is quite hard to get a good historical perspective, from the technical literature alone; and much harder to understand what is going on in the Russian or Japanese perspectives, than in Paris or Princeton. We ought to be trying to give a good broad coverage, by survey article standards, with reasonable references. We ought to be giving the sort of background that makes the current preprints more accessible (so, basic definitions to answer 'what the hell is X?' questions). We should reach for a good overview of the whole tradition, and what is going on globally. I don't think it is so sensible to aim to compete directly with the conference literature, say. WP ought to complement academia, and make the effort to explain 'how it all fits together' and 'why any of this matters' - which academics generally don't find the time for. Charles Matthews 21:01, 30 May 2005 (UTC)
Interesting. (BTW thanks for your time in answering these questions; you must be a pretty busy guy.) I certainly agree with your last sentence, i.e. that WP should help explain 'how it all fits together', I'm very keen on that. I'm also very keen on giving historical perspective. On the other hand, it seems that WP provides an ideal vehicle for a piece of writing to start off as a survey article, but then slowly morph into something providing textbook level detail, while nevertheless remaining a survey article to a reader not concerned with details or proofs. (They just don't have to follow all the links.) Mathematics seems to be a subject area especially suited to this, since there tends to be less disagreement about correctness than in most other academic discplines.
I'm sure this meta-wiki discussion has been had by plenty of people already :-). Perhaps I should spend some time reading what everyone else has had to say. As I am a wiki newbie, I am probably suffering from some kind of wiki-thrill, believing that WP can solve all of humanity's problems. It does seem to me to be a genuinely new form of communication/publishing media, which as you can tell I find very exciting.

WP can do some good, no question. Trying to audit quite how much progress is interesting, taxing and sometimes chastening. The first five years, for mathematics, is going to look like 10000 pages with much 'core' material. Chronologically the solid coverage can get us into the 1950s, mostly; but not past 1960. I would project, that in 2010 it would look more like 1970 rather than 1960; and even that is ambitious and would require much more expertise in the 'rarer' topics (algebraic geometry and topology, for example) than we currently command. I'm quite upbeat, but it is still very easy to find the gaps. Charles Matthews 10:13, 31 May 2005 (UTC)

Hi Charles, Dmharvey. I don't mean to butt in on this conversation, but I've enjoyed reading both of your thoughts in this and the above section (the "multiple audience" issue particularly), and I would expect others involved in Wikipedia:WikiProject Mathematics would find these discussions interesting and beneficial as well, and perhaps even want to join in ;-) However if you prefer to keep this a private discussion, I respect that. Paul August 15:13, May 31, 2005 (UTC)

As far as I'm concerned, I'm not saying anything private - go ahead, Paul. Charles Matthews 15:27, 31 May 2005 (UTC)

Charles, yes, I didn't really think that what you were saying was meant to be private (I was just trying to allow for the possibility that you or Dmharvey might prefer to have a two-person conversation). And anyway there isn't anything I really want to add to the discussion — yet. I just think that you guys have been having a couple of interesting discussions that others would be interested in also. So I was trying to encourage you to consider discussing these ideas on Wikipedia talk:WikiProject Mathematics. (By the way thanks for your vote in support of my admin nomination ;- ) Paul August 16:45, May 31, 2005 (UTC)
As far as I'm concerned, nothing on WP is private :-) (Unless of course you're using PGP, but that, as they say, is just not cricket.) I'm quite happy for anybody to move the above text to an appropriate venue, or to do whatever is appropriate. Dmharvey 18:22, 31 May 2005 (UTC)

Wow, yes, agree with both Charles and Dmharvey. Realistically speaking, WP has huge gaps in just about any topic, and will need to grow at least 50-fold to fill these gaps in. It will take many many years for this to happen. But I also agree with Dmharvey in that it seeems inevitable that WP will become the authoritative reference in a decade if not sooner; its already beyond in many areas.

But please note that we will have to tackle many serious structural issues first; and if these are not solved, then it will make growth harder. For example: Charles "survey" articles are already outnumbered by more "mundane" articles that mostly list facts. (I myself generate "mundane" articles because I'm not knowledgable enough to write surveys in any but a few fields, and those fields bore me...). I would like to see some system that somehow makes the survey articles more visible, more prominent. They tend to be lost in the mire.

I don't know how to fix this. Maybe have different classes of articles? This is kind of like the "proofs" discussion, but in reverse. With proofs, the problem is how to hide this third-tier material so that it doesn't impede article flow. With "survey articles", the problem is how to highlight them above and beyond the rest of the bulk.

Note also the existing tension between "simple" and "advanced" treatments of the same material is going to get worse. We'll need to devise some mechanism for dealing with this, as I wonder if the current ad-hoc approach can last. I've had Oleg delete some of my edits because they were too advanced, I've had Fropuff delete some of my edits because they were too trivial. I'm not complaining, I'm rather trying to make note that this is a potential problem area that will recur in WP and is worthy of attention. linas 00:19, 4 Jun 2005 (UTC)

Yes, the greatest problem I'm having is where to put things. I really think we need to structure all our articles hierarchically and make it clear what should go where. --MarSch 10:50, 4 Jun 2005 (UTC)

In the context of Wikipedia, I think I have come to the opinion that the issues being discussed do not really raise any problems.

Suppose that we have an article X that discusses topic Y. There are lots of people who might end up looking at page X. A priori, they might be arriving there with a huge range of different levels of mathematical experiences. However, I claim that the gap between

  • The lowest level of experience a person could have before they conceivably could get anything on that topic; and
  • The highest level of experience a person could have and still be interested in that topic,

is actually not that large. It may seem large, but there's some kind of "logarithmic scale" operating here. I think it is possible to have a well-written introduction that can simultaneously branch off to cover many different levels of pre-experience. Obviously, not everyone will be able to write that introduction, since some people simply don't have the background to see it all in context. But, almost by definition, someone will have that context, and will (eventually) supply it. Dmharvey Talk 11:34, 4 Jun 2005 (UTC)

Mostly agree, just please note that there are some exceptional pages: Torus and Laplacian operator are examples. Torus can run the range of middle-school "volume of a torus" to grad-school "Teichmuller space". Laplacian runs from engineering school to harmonic analysis. Maybe these can be treated on an ad hoc basis. Somewhere I suggested an "educational trampoline" for things like "torus", since it can be a doorway to higher math for younger students. linas 17:03, 4 Jun 2005 (UTC)
One way to deal with it is to take advantage of Wikipedia's subsection facility. The first paragraph is a corse overview, which should be understandable to the journeyman, and will probably have little valuble content for the expert. It's allright it the total novice is a *little* floored by it, because the first proper section starts on the ground floor and explains things simply. Linkouts are good, but we shouldn't expect even a novice to have to search 10 links deep in order to understand something. Following sections can build up from there. Experts who know everything can skip to the bottom, where the heavy theory lies, and the novices can stop after a section or two, when they have a good overview of the topic, but before they get into the deep math. The trick is to compromise, and cede the top of the article to the complete novices, and only put the Masters level theory at the bottom. (Summary: Novice on top, Intermediate in the middle, Expert on the bottom.) 15:35, 22 Jun 2005 (UTC)

I would also like to mention something else about "authoritativeness" of WP. It seems to be widely acknowledged that there are issues with reliability in WP, and that this seems an insurmountable barrier to WP becoming useful to the academic community (in the present discussion, the academic mathematical community). I agree with the first half of the sentence but not the second half. Something can be useful even if it's inaccurate. And it seems that WP has a strong tendency to become more accurate over time, at least on topics that are not too sparsely covered. In the real world, no one source is enough anyway. When I want to learn about a maths topic I don't know much about, I don't just get a book out of the library. If I really want to learn something, I get at least three books or journal articles, and talk to my colleagues, asking them what their point of view is on the whole subject area, and where they think is a good place to read about it. Dmharvey Talk 11:34, 4 Jun 2005 (UTC)

I'm wondering if some semi-formal peer-review/voting/audit-trail type system might help with authoritativeness. I'd like to mark up a page or a portion of a page to somehow state "yea verily I have reviewed this and attest to its accuracy". Kind of like wear marks. Have no idea how to implement this. linas 17:03, 4 Jun 2005 (UTC)
I've sometimes wondered if a symbiosis with Planet Math might work; they'd hold peer-reviewed content, which the public cannot edit. It could be copied from WP after some sufficient quantity of review. linas 21:35, 4 Jun 2005 (UTC)
That's why the project we have here is called Wikipedia:WikiProject Mathematics/PlanetMath Exchange (please note the word Exchange; it was hoped that the map from PlanetMath to Wikipedia is invertible, and PlanetMath people could use our stuff). Oleg Alexandrov 23:56, 4 Jun 2005 (UTC)

On the other hand, on the more general topic of "long-term future of mathematics in WP", I have some other concerns. My first concern regards typesetting. I summarise by saying that in the present situation, I don't think WP has sufficiently sophisticated typesetting for serious mathematical work. This may become a long term problem, because one important group of people we would like to attract to write articles, serious mathematicians, will be put off by something that visually looks amateurish. For those who don't believe me, I suggest trying to write a complete paper in LaTeX. It's incredible how LaTeX is able to make even completely incoherent babble look like the most brilliant piece of mathematics written since the 16th century. This might improve if browsers improve, I'm not sure.

A second concern is that there are other interesting things that a WP-like system could conceivably do, but which the current software does not support. For example, it would be lovely for WP to support a parallel development of some kind of formal proof system; i.e. symbolic manipulation software where people could enter formal proofs which are checked automatically for correctness. I don't believe such a system exists yet, except in fairly primitive forms. I think there have been a fair number of attempts, but I haven't heard of any that have scaled up well. I think in time, the collaborative nature of something like WP will solve the scaling-up problem. Then, if you believe the axioms that the system is founded on, and you believe that WP is doing its proof checking correctly, then you can be happy that the theorem you are looking at is OK. (Please don't take this paragraph too seriously; there are ENORMOUS problems, both theoretical and practical, with automated proof systems, and I just wanted to throw it up as a random thought.)

OK I've really chewed up enough bandwidth now. Dmharvey Talk 11:34, 4 Jun 2005 (UTC)

That's an interesting concept (mixing automated reasoning with mathematical exposition), but that's another beast entirely, in my opinion. You probably are thinking of Mizar or Isabelle? Proofs there tend to be long and not easy for the non-expert user to construct.--CSTAR 14:59, 11 Jun 2005 (UTC)
The proofs do tend to be longer, but the difference is getting smaller nowdays. I put a small pdf file at [12] with an example of modern declarative formalized proof style (generated by Isabelle). Having a link to a formally verified proof of a theorem certainly increases "authoritativeness". Formalized proofs of many theorems mentioned in Wikipedia:WikiProject Mathematics are accessible on the web. --Slawekk 23:49, 14 December 2005 (UTC)

Wallpaper groups

Dear peoples, I have spent quite a number of hours the last few days working on Wallpaper groups. It looks almost completely different now, and I hope it is an improvement.

The only thing I plan to do with it for the next few days is finish labelling the pretty pictures. Apart from that it is in all of your capable hands.

Then I need to take a break from wikipedia, so I can do some other things.

I will return in a few weeks.

Dmharvey Talk 17:09, 4 Jun 2005 (UTC)

Wow! Paul August 18:31, Jun 4, 2005 (UTC)
That is indeed stunning. --14:51, 11 Jun 2005 (UTC)

I've just come across a nice template slapped onto talk pages of chemistry ({{chemistry}}):

WikiProject on Chemistry This article is supported by the WikiProject on Chemistry, which gives a central approach to Chemistry and related subjects on Wikipedia. Please participate by editing the article WikiProject Mathematics/Archive2005, or visit the project page for more details on the projects.

Should/do we want to have something similar? Might bring more people to the project. --MarSch 18:06, 5 Jun 2005 (UTC)

Some reaction might be nice. Any reaction. --MarSch 13:24, 12 Jun 2005 (UTC)
I didn't react since I don't have much of an opinion either way. It is quite a bit of work, and I think our current approach of inviting people personally to have a look works much better; on the other hand, it doesn't do any harm, and it will rake in some more people, so go ahead. -- Jitse Niesen 20:45, 12 Jun 2005 (UTC)

Personally, I hate banners. Ditto for topic templates, and such. I suggest that you just watch a lot of pages. If you see the same person making good edits on a number of pages, invite them here. I made hundreds of edits before I even bothered to look at this page, and am deeply suspicious of anyone who would be interested in process who hadn't been an active editor first. linas 04:16, 13 Jun 2005 (UTC)

List of lists of mathematical topics

There is a proposal at Talk:List of lists of mathematical topics to reformat that list according to subdivisions of math. Comments welcome. Oleg Alexandrov 19:51, 5 Jun 2005 (UTC)

WP etiquette question

There has been a recent addition to Pythagorean theorem by which although appears to be in good faith, I feel is unnecessary. I tried for a while to think of a way to rephrase it so that it would fit, but eventually decided it just shouldn't be there. What's the best thing to do in a case like that? Thanks Dmharvey Talk 11:59, 6 Jun 2005 (UTC)

Write to the talk page explaining your reasoning and why you're going to delete it. Then be bold and delete it. Be firm but polite. If the editor clarifies or suggests alternative wording, be reasonable. --Tony Sidaway|Talk 12:45, 6 Jun 2005 (UTC)

OK thanks. I'll try that. Dmharvey Talk 13:02, 6 Jun 2005 (UTC)
Try moving it somewhere else (another article), if it is information. If it's just words then delete. --MarSch 14:57, 6 Jun 2005 (UTC)
Assuming that you have the time and find the right spot, that's a good idea. Otherwise, just moving the text to the talk page, together with your explanation for why you moved it, is perfectly fine. Deleting the text altogether, with an explanation also works. Oleg Alexandrov 15:09, 6 Jun 2005 (UTC)
One of the exasperating things about WP is suddenly to find an article changed in totally bizarre ways. It 's very very hard to be polite in these circumstances. --CSTAR 15:55, 11 Jun 2005 (UTC)
It can be exasperating, but you have to expect it. There will always be new users coming into Wikipedia who will act in very unusual ways. It is just the price we pay for the open model, which has been so enormously successful. And of course politeness is always the best strategy, no matter the circumstances or the exasperation level. Paul August 16:47, Jun 11, 2005 (UTC)

carmichael's theorem

Is my brain broken, or is this theorem just silly? It seems to be saying that the definition of the carmichael function is, in fact, identical to the definition of the carmichael function. Surely the theorem should instead say something like, "the recursive formula given for the carmichael function is correct, i.e. satisfies the property alluded to in carmichael's theorem"? Really these should go into the same article with a redirect on one of them. (And then one day I'll write something about larger examples of carmichael numbers, and of its relevance to primality testing, and fix up some nasty markup.) Dmharvey Talk 23:57, 6 Jun 2005 (UTC)

  • Aaah. Just found Carmichael number, strangely enough not linked to either of the above articles. That makes life easier. Dmharvey Talk 00:01, 7 Jun 2005 (UTC)

The recent total re-write of list of lists of mathematical topics

(NOT to be confused with list of mathematical topics)

User:Samohyl Jan has completely re-written this list of lists, with some input from me as well.

Please vote on list of lists of mathematical topics at Wikipedia:Featured_list_candidates#Nominations. Michael Hardy 00:23, 9 Jun 2005 (UTC)

I'm tempted to support, but I'm not really into featured lists. --MarSch 10:49, 9 Jun 2005 (UTC)


What about a specialized wikify template for mathematics articles? This might make it easier to keep our to-do-lists recent. See also the discussion at TFD about some of these templates: Wikipedia:Templates_for_deletion#Template:Foo-wikify --MarSch 10:58, 9 Jun 2005 (UTC)

I really think this would work much better than Wikipedia:Pages needing attention/Mathematics since categories automatically keep an uptodate list of articles. If you still want to vote, you can do so at Wikipedia:Categories_for_deletion#Category:Foo_articles_that_need_to_be_wikified. --MarSch 13:23, 12 Jun 2005 (UTC)
I am not sure about a Category:Math articles that need to be wikified, for the reasons given in the CfD discussion (everybody can wikify), but a Category:Math articles needing attention does seem to have some use. -- Jitse Niesen 20:04, 12 Jun 2005 (UTC)

Article on VfD

I nominated topic-based vector space model for deletion because this is a method proposed in a paper in 2003 (see the external link in the article), so it is very new and too early to say if it is proeminent. So I think it is not yet something to be included in an encyclopedia. But I am not 100% sure. I wonder if other mathematicians would visit that article, then post their opinions on the VfD page. Oleg Alexandrov 03:37, 10 Jun 2005 (UTC)

I would vote "merge as a note in the VSM article and redirect". Pcb21| Pete 07:45, 10 Jun 2005 (UTC)
vector space model is by the same author... --MarSch 09:39, 10 Jun 2005 (UTC)

WikiProject logic

Encouraged by User:Paul August on Talk:Aristotelian logic, I'm posting an invitation to comment on the idea for a WikiProject for Logic. I have a draft proposal at User:Chalst/WikiProject Logic proposal, and I am interested in:

  • Indications of interest
  • Criticisms of the what is on the page

Many thanks in advance for your comments. --- Charles Stewart 15:59, 10 Jun 2005 (UTC)

Related articles

Related articles with similar content and unclear interrelations are the biggest problem I am facing. A mild version of this is the group, group theory combo which can usually be sorted out, although I think this has often not happened yet, but what to think about: vector (spatial), vector field, vector space, tangent bundle, tangent space, and the also to these related scalar, scalar field, tensor, tensor field, Tensor_(intrinsic_definition), Intermediate_treatment_of_tensors, Classical_treatment_of_tensors and maybe more. What I would like to know is which you think the possible content of these articles should be in. Possibly using templates subarticleof}} and seesubarticle}}. I would welcome any ideas. --MarSch 14:00, 12 Jun 2005 (UTC)

For now I don't have the time to take a look at all the articles; but on principle, I would think that the fact that the articles are loosely organized (with repetitions occuring in places) is a good thing as this allows for reading one article independent of the other. Also, from what I saw, vector (spatial) is a less abstract/more physical/geometrical article as compared to vector space, and integrating the two could be a mistake. In short, I am for some anarchy on Wikipedia. :) Oleg Alexandrov 14:32, 12 Jun 2005 (UTC)
The problem with anarchy is that it is not clear where information can be found and by extension also not clear where information should be contributed. If the efforts were a little better organized all of these articles might have already been featured, instead of the cluttered form most are now in.--MarSch 15:10, 12 Jun 2005 (UTC)

Yes, well, be careful. These articles treat similar topics, but not the same topic. Vector bundles are not vector spaces; and the former links to the later in the introductory sentence. Vector bundles are a kind-of fiber bundle ... I discovered early on that attempting to make large re-organizational edits can often sink a lot of time, while failing to improve quality. I'm surprised you're not sensing this yet ... Personally, I prefer smaller articles, with a given topic spread out across multiple articles, than trying to jam everything into one article. As to some repetition, that's OK, too. I'd prefer to see articles grow "organically" by accretion. After lots of accretion, they may look poor, in which case they can be restructured. However, trying to optimize content across multiple articles makes me very nervous. In particular, such a re-organization implies that you are trying to impose your world view on something that had evolved quite differently to begin with. Catholics and Protestants are both Christians, but neither would agree to the restructuring suggested by the other. linas 04:02, 13 Jun 2005 (UTC)

I agree that articles on both vector spaces and vector bundles (I didn't even mention this one) are warranted and also tangent bundle, but probably not vector (spatial), vector field and tangent space. Vector (spatial) really about vector spaces and some Euclidean metric, vector field ought to be part of vector bundle and tangent space should redirect to tangent bundle. --MarSch 14:34, 13 Jun 2005 (UTC)
I agree very much with Linas. MarSch, I think you should proceed with caution, if at all. And please consult frequently with some of us; it is good that whatever you do have the community support.
Now, in my view, the biggest problem the math articles face is not what you mentioned above. Many articles just need careful reading, fact checking and minor fixes. One should also watch a lot for vandals, trolls, or just misguided, misplaced or poor edits. If you feel full of energy, instead of rewriting and reorganizing things, I would suggest you check more often the recent changes to the list of mathematical topics (go to that link then you will see what I mean). Janitorial work is not very glamorous, but much needed. Oleg Alexandrov 14:17, 13 Jun 2005 (UTC)
Janitorial work is all very nice, but it doesn't improve article. --MarSch 14:34, 13 Jun 2005 (UTC)
I agree with Linas and Oleg that most of these articles should remain separate. Tangent space and tangent bundle should remain separate for the same reasons that I mentioned on Talk:Cotangent space. Vector fields are often studied by advanced calculus and physics students long before they've every heard of things like manifolds, let alone vector bundles. Vector (spatial) — also known as vector (physics) — is how vectors are treated in freshman physics courses (where they almost never worry about vector spaces as such) — this article should definitely remain separate. I do think that the articles on tensors are rather scattered and could do with some more cohesion. However, this needs to be done carefully, with much discussion, to avoid alienating certain user groups. -- Fropuff 16:15, 13 Jun 2005 (UTC)

Kettle Principle

I ran into this article, and don't know what to do about it. Any opinions? Oleg Alexandrov 05:25, 16 Jun 2005 (UTC)

A very bad version of the "tea making joke", probably vfd or even d --MarSch 15:43, 16 Jun 2005 (UTC)
I've heard of the joke (and there is a better version in Mathematician), but I've never heard of the "Kettle Principle" (no google hits), unless someone can come up with a reference, I would support deletion of the the page via VFD. Paul August 20:31, Jun 16, 2005 (UTC)
I first wanted to turn Kettle Principle into a redirect to Mathematician, which wouldn't require listing it on VfD, but on second thought I don't even want the redirect. I don't see why it would be a candidate for speedy deletion (which of the criteria of WP:CSD applies?), so I listed it on VfD. Please vote at Wikipedia:Votes for deletion/Kettle Principle. -- Jitse Niesen 23:08, 16 Jun 2005 (UTC)

Vector space example x

Vector space example 1 and Vector space example 2 and Vector space example 3 are really horrid. They are complete verbosity. Maybe we should delete them. --MarSch 15:48, 16 Jun 2005 (UTC)

Yes, I wrote examples of vector spaces as a replacement for these pages. But they are still lingering around. I would VFD. -- Fropuff 15:54, 16 Jun 2005 (UTC)
I would support their deletion. Paul August 19:53, Jun 16, 2005 (UTC)
All three are now listed on Wikipedia:Votes for deletion/Vector space example 1. -- Jitse Niesen 23:08, 16 Jun 2005 (UTC)

Pulation square on vfd

The article pulation square, which in my opinion is a perfectly fine math stub, has been nominated for deletion here. Please share your thought there. Thanks. Paul August 15:30, Jun 18, 2005 (UTC)

This is not a legit VfD. Its an act of vandalism by an extremely foul-mouthed 14-year old newcomer to WP (User:Big al kicks ass). I reported it as such to Wikipedia:Vandalism in progress. linas 17:34, 18 Jun 2005 (UTC)

Category:Physics: general/basic/introductory concepts

We're currently having a brain storm on Category_talk:Physics about the following questions:

  • How best to distinguish the articles that genuinely cover general topics from those that have been moved into the main physics category recently and jsut aren't specified yet.
  • What to call a category for mathematical tools, such as tensors, and if this makes sense at all.

You're cordially invited. — Sebastian (talk) 07:50, 2005 Jun 20 (UTC)

Democratic peace theory

An excessively original believer in this piece of social science questions the following observation, which seems trivial to me:

(... The proper odds to judge a set of data which satisfies a theory deriving its parameters from that [identical] data is the chance that the data would satisfy the theory using, not those particular parameters, but any possible parameters.)

If one of you can think of an exact source, contact me or comment on the article's talk page. Now at bottom. user:Pmanderson

With due respect to the person who actually wrote the quote above, it seems to me of little value and poorly phrased. Oleg Alexandrov 16:13, 21 Jun 2005 (UTC)
Amateurishly phrased, and trivial; but apparently not allowed for by the political scientists in their calculations, and denied by User:Ultramarine. Septentrionalis 17:27, 21 Jun 2005 (UTC)
I think this is highly non-trivial, even ignoring the fact that the GUT is supposed to have no parameter freedom. It does not mention by what probabillity distribution that chance is to be calculated. By incorporating that distibution into your theory you can fix the outcome of the judgement to probably a very great extent. Thus I think the statement is highly ambiguous or even non-sensical. Also why does it say "judge a set of data"? Surely the theory is what you want to judge. Theories are judged by their predictions, their intuitive explanatory power and Ockham's razor. --MarSch 09:51, 22 Jun 2005 (UTC)
Thank you. I think the following phrasing is what I mean: see if you can object to the following:
Using a set of data to determine the parameters of a theory, and then validating the theory by applying it to the same set of data is a weak form of proof. Normal statistical tests assume the theory is independent of the data. Septentrionalis 16:13, 22 Jun 2005 (UTC)
I'll object. I know very little about statistics, but it was my impression that this is exactly how statistics is done. When a medical trial tests the effectiveness of drugs, they don't try to fit parameters to some of the data, and then try to validate with another chunk of the data. They try to fit all of the data; they validate the theory by looking at the standard deviation and the correlation. So its not a weak proof at all, its the standard way by which statistics is done. I thought User: Michael Hardy was into statistics. linas 00:42, 23 Jun 2005 (UTC)
medical tests just try to find out which out of a few treatments works best. There is no parameter fitting and hardly any theory, just facts that have been measured.--MarSch 10:39, 23 Jun 2005 (UTC)

So far I'm still finding this very vaguely expressed. I'm not sure what Septentrionalis a.k.a. user:Pmanderson, is trying to say. Michael Hardy 01:48, 23 Jun 2005 (UTC)

The context is in this version; the section called Significance. Rummel, a political scientist, is trying to prove a statement about all "sufficiently nice" democracies: to wit, that they don't go to war with each other. He narrows his sample of democracies by excluding those states with less than a certain proportion of voters, and less than a certain age. These are parameters, in the real sense of the word.
It is possible that he chose his values parameters precisely to get as many democracies, and as few wars, as possible. Let us suppose this true. If so, he is then testing the resulting theory against the historical record for the same period. I believe that this is a weaker test than if he had chosen his parameters a priori and then looked at the historical record.
This seems to me actually a fairly trivial observation, but it is the one that was challenged. (And my statistics may be rusty; I was an actuary some years ago, after all.) Septentrionalis 02:41, 23 Jun 2005 (UTC) -and after previewing I see the error of agreement in the paragraph.


Allright, let me say some things. I think what we are talking about here is not a theory at all, since it has no predictive power, but just a statement of fact. The fact that if you define liberal democracy so and so, then there is so and so much war. If you define it somewhat differently you may get a different picture. For an informed picture you should present a few of these statements ranging from a restrictive to a broad def. If you don't like that picture then you can leave out some data (a few statements) thereby deceiving people into thinking what you want them (and possibly yourself also) to think. This you might call fitting the parameters. Looking at a single set of parameters is surely better than this, but also leaves much to be desired, as I explained.--MarSch 10:56, 23 Jun 2005 (UTC)

OK, I understand now. What Rummel should have done is to graph number of wars as a function of parameters (voting age, population size, etc.). If he finds that the graph is flat (i.e. independent of the parameter) then he has a theory. If there is a strong correlation between the parameter and the number of wars, then he has no theory until he explains why there is a strong correlation. So maybe there is indeed an error of methodology. Either that, or a misinterpretation of Rummel's work. linas 15:44, 23 Jun 2005 (UTC)
I mostly agree with the Significance section. If you only have one set of data and you have to first deduce a theory, you normally randomly split the data set. The first part is used to find a theory, including the parameters, and the second part is used to verify the theory.
I think it's a valid theory and might be true, but so far it's not proven, there is a deep flaw in the statistical argument. Future will show if the theory is right. Markus Schmaus 18:35, 23 Jun 2005 (UTC)

Morton's theorem

I ran into this article today. From what I see, this article is the thoughts of a certain Andy Morton about poker posted on (Usenet) around 1997. It seems that his post was rather word for word pasted in this article, and that this article is not encyclopedic. How about voting it for deletion? Oleg Alexandrov 19:53, 25 Jun 2005 (UTC)

My first impression is not that it should be deleted. However, it may be a copyright issue, so I asked the user who posted it if this could be clarified, see User talk:Fekko. If I do not receive an answer, I will list it on WP:CP. You may also want to confer with User:Revolver, who is apparently responsible for our article on the Fundamental theorem of poker. -- Jitse Niesen (talk) 20:56, 25 Jun 2005 (UTC)
First of all, although it's math-related, it's not really a "theorem", so I deleted it from that category. One thing that's not made clear, is that the first paragraph appears to me to be Caro's words. This makes a big difference in reading the post. But, it is definitely a legitimate concept, in fact, it may be one of the most important concepts in all of poker. I'll try to summarise the gist of the post, esp. the example, so as to minimise the potential copyright problems. But, it's definitely encyclopedic. Revolver 13:20, 26 Jun 2005 (UTC)

Birthday distribution

Here's another article on which input is needed. Probabilists out there, do you think this is rescuable? So far, it looks like a table of data obtained by using a paper from 1981. Oleg Alexandrov 20:13, 25 Jun 2005 (UTC)

This is a copy of, but I doubt that it is copyright-able as it's basically a table of numbers. However, I don't see much encyclopaedic value in it. -- Jitse Niesen (talk) 21:04, 25 Jun 2005 (UTC)

Proof of... articles

Any objections to moving Proof of Leibniz formula to Leibniz formula and Proof of Viète formula to Viète formula? I moved Proof of Wallis product earlier, but didn't notice these two. Are there any other proof of X articles without a main X article that should be handled similarly? - Fredrik | talk 21:22, 25 Jun 2005 (UTC)

Actually, it seems that Leibniz formula should more properly be a disambiguation page... - Fredrik | talk 21:22, 25 Jun 2005 (UTC)
No objections. --MarSch 10:22, 26 Jun 2005 (UTC)

Hyper generalized orthogonal Lie algebra

A badly written article should not be deleted, rather cleaned up. That is the conventional wisdom, but this particular article is trying my patience. Could anyboyd knowing this stuff take a look and say if this at all makes sence? Thanks. Oleg Alexandrov 22:07, 25 Jun 2005 (UTC)

The mathematics is probably OK. It's about explicit expressions of things like the Lie algebra of the Poincaré group, which is a semidirect product, in a block matrix way. Which is perfectly sensible. There is some odd language, but it is really mostly about writing things down in a 'dimensionless' way (c=1, that sort of thing). I wouldn't vouch for the title being standard. Charles Matthews 22:27, 25 Jun 2005 (UTC)

italic "i"s for the imaginary unit are being changed to non-italic, please comment

Wurzel is proposing here that the imaginary unit be represented using a non-italic i, and has been changing articles accordingly. The first seven books I've just pulled from off my shelves, all use an italic i. Please share your thoughts on the appropriate talk page(s). Paul August 17:04, Jun 26, 2005 (UTC)

scope of derivative article

There's an interesting discussion going on at Talk:Derivative concerning the scope/audience of the article. I'd be interested if anyone supports what I have to say. Alternatively, if you disagree with me, please add your voice. When I hear enough I'll shut up :-) Dmharvey Talk 00:25, 27 Jun 2005 (UTC)

The discussion in question is at the ==Scope of derivative article== heading and below it. Comments are very welcome (requested), since the issue of what to expect from the audience reading our articles is (I think) one of the more pressing ones this project faces. Oleg Alexandrov 03:06, 27 Jun 2005 (UTC)

Relaunch of Mathematics COTW

For those who don't know, the Mathematics Collaboration of the Week has been re-launched. Please nominate and vote for articles to focus on each fortnight. Both stubs and articles that are not stubs, but are confusing or poorly written, are acceptable. NatusRoma 29 June 2005 05:42 (UTC)

Please vote!

Please vote at Wikipedia:Featured picture candidates/Ford.circles.gif. The selection criterion includes the following:

the images featured on Wikipedia:Featured pictures should illustrate a Wikipedia article in such a way as to add significantly to that article

and stated that merely being a spectacular picture is not a sufficient qualification. This picture will probably not be considered spectacular; it's very simple. But it can make clear to ordinary laypersons the concept explained in Ford circle that would otherwise probably be understood by few other than mathematicians. <hubris> Thus in "illustrat[ing] an ... article in such a way as to add significantly to that article" I think it excels. </hubris> Michael Hardy 30 June 2005 23:10 (UTC)

Renaming the derivative article

There is a proposal at Talk:Derivative#move to differentiable function to move that article to Derivative (high school version) or some other similar sounding title. The reason seems to be that the derivative article as now written is not representative about what derivative is in mathematics, rather, it focusses on the most elementary calculus definition. Comments welcome. Oleg Alexandrov 1 July 2005 02:20 (UTC)

Don't say derivative (high school version); say derivative (elementary calculus), or something like that. Michael Hardy 5 July 2005 01:02 (UTC)

The ugly theorem

I found this article about a rather elementary fact in number theory. Anybody heard it called that way? Google yields nothing about this particular theorem. Oleg Alexandrov 1 July 2005 03:04 (UTC)

I don't understand what the "theorem" or elementary fact aspect is. It just looks like a property possessed by three particular numbers. Can anyone elaborate? (Google no help to me either) Kinser 1 July 2005 03:50 (UTC)

Checking the page history, it looks like an anonymous user with a tenuous grasp of English just typed up some info about something they found in a book or online, which then got copyedited into the current version by other people. The original version of the article didn't actually claim that Masahiko Fujiwara named the result the ugly theorem, though it does suggest that the "theorem" is that only the given three numbers have this property. In the absence of any other information about it, I would be inclined to delete the article on the grounds that the information has not been able to be verified. - dcljr (talk) 1 July 2005 05:13 (UTC)
I cannot verify it. Let's get it deleted. --MarSch 1 July 2005 11:43 (UTC)

Errors in articles

I don't know if this is the right place to comment on this; please move if you know a better place.

About 3 months ago, I added an intentional error to the page about "Distribution", date/time "21:33, 31 March 2005 (→Formal definition)". Of course the type of convergence is weak, not strong. Jitse Niesen was so kind to move the error part in the text, and has been unnoticed until now.

If such a major error in a basic mathematical article can survive this long, how much errors will there be in the more advanced subjects? For me this is enough proof not to trust Wikipedia articles. Hugo 1 July 2005 11:37 (UTC)

you shouldn't trust anything that you've not seen the proof of. --MarSch 1 July 2005 11:46 (UTC)
I don't trust your statement. I even don't trust my own statements. With such an argument there is no need to make a precise encyclopedia. I was in doubt about adding a statement like "Don't just say you can never trust your sources" but I hoped such a non-argument wouldn't be said. Hugo 1 July 2005 12:01 (UTC)
How's this for a non-argument: If you're intentionally introducing errors into articles, why should anyone engage you in serious discussion? In any case, see Wikipedia:Replies to common objections. - dcljr (talk) 2 July 2005 01:39 (UTC)
There is sad truth in what Hugo is saying above. But this is not surprising. There are 7000-8000 math and math-related articles on Wikipedia (7995 items on the list of mathematical topics as of now). There is not enough time and man power to check all contributions for mathematical correctness. There is not enough manpower even for style fixes. Besides, I am sure that a good chuck of those articles represent "dark matter", articles which are not on the watchlist of any active Wikipedians. One of course can check the changes to them from the list of mathematical topics, but again, who has the time? So, while Wikipedia can be lots of fun for editors (me at least :) and a useful source for readers, ultimately it is not much more reliable than a lot of other information on the internet. And there is not much to be done about this. Oleg Alexandrov 2 July 2005 02:21 (UTC)
There are lots of errors in wikipedia articles, we just corrected a subtle error in linear independence, but as a survey showed, many textbooks contained the same error. I found wikipedia very helpfull in several cases, but you're free to trust or not to trust any source you want to. Markus Schmaus 2 July 2005 03:18 (UTC)

Perhaps you might be polite enough to fix the error, now that it has been spotted, and now that the point has been made  :-) (Although I see that there would be additional mileage gained by not fixing the error, since then you could point out that the error has not been fixed even after explicitly pointing it out in a discussion forum like this....)

But seriously... I agree that this is a problem, but probably not as big of a problem as you are making it out to be. You said: "For me this is enough proof not to trust Wikipedia articles." I agree: you shouldn't trust wikipedia articles. That should have been clear from the first moment you heard of the concept of wikipedia. And I don't think it is at all a non-argument to say "don't trust your sources". I genuinely believe in that argument. Trust is not black and white. It is possible to have a spectrum of trust in things you read, and a lot of it depends who wrote it and what your opinion is of them.

You also said: "With such an argument there is no need to make a precise encyclopedia." In my opinion, this is a vacuous statement; it is impossible to make a precise encyclopaedia. Precision is an ideal; I think generally wikipedians strive towards it, and they do a reasonable job, but I'm under no illusions of it being completely attained. However, it is possible to make a useful encyclopedia. And I think wikipedia is already such an object, and becomes more useful every day. An article can still be useful, even if it contains errors. (And I think most articles do not contain deliberate errors – the most insidious kind). For this reason, I still welcome your contributions, as long as the bulk of them are useful :-) Dmharvey Talk 2 July 2005 12:48 (UTC)

I sometimes wonder what percentage of Wikipedia's inaccuracies are there because someone felt the need to make this point. Isomorphic 2 July 2005 19:00 (UTC)
I concur with the above posts: I trust Wikipedia generally far less than textbooks or mathematical papers (which does not mean that they are perfect), not only because of the anonymous edits but also because most articles are not written by experts and most are not reviewed by experts. Furthermore, I personally am more careful when writing a mathematical paper than when editing the Wikipedia, and I guess this is true for most of us. It is highly unfortunate that Hugo mentions a weakness on which most of us agree without offering any suggestion for overcoming this weakness, and also that he hasn't tried yet to amend the error he deliberately introduced. For reference, this is all about the following sequence:
"The space D'(U) is turned into a locally convex topological vector space by defining that the sequence (Sk) converges towards 0 if and only if Sk(φ) → 0 for all test functions φ; this topology is called the strong (operator) topology."
Here, D'(U) is the (continuous) dual of the space of test functions. The topology is certainly not the strong operator topology because the space D'(U) does not consists of operators. Hugo seems to claim that it's the weak topology, but my impression is that it's the weak* topology. Can he (or anybody else) explain this? -- Jitse Niesen (talk) 2 July 2005 20:09 (UTC)

Lets get real. It appears that User:Hugo doesn't understand the process by which mathematics is actually done, and how research is published, much less how WP articles are written and corrected. A WP article can only be corrected when someone who is knowledgable and interested in a topic spots an error and corrects it. The error was presumably not corrected because there were no readers who were capable and interested in pursuing the particular claim. There's two ways to spot the error: one way is to be extremely knowledgable on the topic, and spot it instantly when the vandalism occurs. Clearly, there is no such person watching this article. The other way is for someone who is weak on the topic, but is interested in it, to be engaged in the processes of performing research, to eventually notice the error. Seems that was not the case, either. There is a third class of readers; those who didn't notice and didn't care. I think the above analysis shows that what Hugo really discovered is something about the quantity and type of readers of WP math articles, and not about the quality of the articles themselves.

If User:Hugo was actually performing research, and actually using WP as a source, then if there were errors in the articles that Hugo was reading, he would have eventually found them. I presume that he'd eventually find them, since I presume he double- and triple-checks his work. If not, and he publishes his work with errors and erroneous conclusions, then he is a fool, and has only himself to blame and not WP.

Ethical norms are such that anyone who is intentionally misleading, such as Hugo was, has crossed an ethical boundary, going in the wrong direction. Equally, if someone was deceived by his deceptions, they can blame Hugo. But, on the other hand, if WP contains honest mistakes (which it does), and someone is lead astray by these errors, then they are unfortunate or dumb or both. Hugo has only demonstrated that one can fool some of the people some of the time; this is hardly new.

If Hugo is interested in refereed math referneces, he should perhaps engage in thinking a bit about the WP and PlanetMath Exchange. We've talked about this here, before.

Everyone who has done research has found errors in published articles and books; some minor, some major. Errors on WP have the opportunity to be corrected, those on the printed page do not. Take a look a look at Talk:Bessel function for a real-world example of an error in a famous and highly-respected book that failed to propagate into WP. We actually have a chance to do better. linas 3 July 2005 00:04 (UTC)

Linas: well said. Dmharvey Talk 3 July 2005 01:04 (UTC)


Weighting curves.png

I've been teaching myself how to make pretty graphs in gnuplot and maxima. Is there a guide to this somewhere? If not, there should be. I will gladly contribute what I have learned today and yesterday. See commons:Image:Weighting curves.png and commons:Image:Hilbert_transform.png for examples. - July 2, 2005 17:48 (UTC)

A guide would be wonderful. I also hope MediaWiki gets support for gnuplot integration some day. Fredrik | talk 2 July 2005 20:17 (UTC)
Such a guide would certainly be very useful, so please start it. I had so many problems getting nice graphs with gnuplot that I reluctantly switched to Matlab (see Commons:Image:Schwarz-Christoffel transformation.png for my latest contribution), but judging from your graph to the right, gnuplot can also make nice pictures. -- Jitse Niesen (talk) 2 July 2005 22:07 (UTC)

A guide would be great; but don't make it into a guide for gnuplot, make it rather a set of "suggested" line weights, styles, etc. for WP, and how to set those things. I note that the above graph looks very nice, whereas the gnuplot default settings look quite poor on WP. linas 2 July 2005 23:12 (UTC)

We have been trying to standardize plots for probability distributions. A summary of the latest definition of a "standardized plot" is at Template talk:probability distribution#Standard Plots. See normal distribution for an example. A basic trick is to make the plot very large, like 6000 pixels on a side, using size 48-64 font size and 17 pixel line thickness, then reduce down to about 1000 pixels on a side using bicubic interpolation. This give a plot with no jagged lines. It is, however, big enough so that someone could download it and use it for projection purposes without pixellation. The display size for the plot is about 325 pixels for the Wikipedia article. Plots are as language free as possible, and uploaded to Wikimedia commons, so that they may be used in any language version of Wikipedia. PAR 3 July 2005 00:01 (UTC)

Any way to do the Gaussian blurring and bicubic interpolation without using PhotoShop? Can GIMP or Matlab do this? -- Jitse Niesen (talk) 3 July 2005 03:03 (UTC)
Aha! Those graphs look really great, and I based mine off of one without realizing they were standardized. Also instructions from MarkSweep. The two I linked to above have instructions in the commons page for reproducing them. One is in gnuplot and the other is in Maxima. I used GIMP to do the blurring and resizing. I wonder if there's a way to get gnuplot to generate the graph the way we want directly to PNG? - Omegatron July 3, 2005 03:25 (UTC)
I did a quick write-up at Wikipedia:How to write a Wikipedia article on Mathematics#Graphs. It would be great if somebody added the specific commands to do this in gnuplot, matlab, gimp, photoshop, and other programs. -- Jitse Niesen (talk) 4 July 2005 14:42 (UTC)
Something about graphs (very shortly) is mentioned in another paragraph in Wikipedia:How to write a Wikipedia article on Mathematics (up several sections). Do you think that part and what you wrote could (should) be merged? Or otherwise, the short part above could mention that more detail is below? I don't know myself how to proceed. Oleg Alexandrov 4 July 2005 15:31 (UTC)
I don't see the two sections. Were they already merged? I will add the instructions for gnuplot and maxima (which outputs to gnuplot) later today. Or you can do it. I included it in the linked images. Too busy right now. - Omegatron July 5, 2005 14:57 (UTC)
The first section is just two sentences in "Main part" (1.2 if you have numbering turned on), starting with "A picture is a great way of bringing a point home". I had already added a reference to the Graph section. -- Jitse Niesen (talk) 5 July 2005 15:26 (UTC)

Dotted framebox around formulas

What do people think of framing important formulas as in this example encountered at differintegral


I myself find it not very pleasing. Oleg Alexandrov 3 July 2005 01:09 (UTC)

  • The template {{ImportantLabeledEquation}} has been put up for deletion on WP:TFD. I've subst'ed the template here for readability, and so that it will be preserved in case of deletion. --Quuxplusone 23:17, 28 July 2005 (UTC)

No I can't say I like it much either. Paul August July 3, 2005 03:51 (UTC)

Not a fan. Doesn't look especially nice, plus it adds extra formatting, which I consider a Bad Thing unless absolutely necessary. Isomorphic 3 July 2005 06:18 (UTC)

I don't care for that particular example either. But as it happens, I have been mulling over introducing equationbox templates for my project of improving the General relativity articles. See the talk page for exact solutions of Einstein's field equations. I would be grateful if anyone has any ideas. Also, I just used a table in the section on Lie algebra of the Lorentz group in my new revision of the article on the Lorentz group. I think the information there is useful in an encyclopedic way, but it would be nice if the table could be shrunk a bit. This problem exhibits the problem I am having in devising equationbox templates; existing infoboxes display some kinds of data in a generally vertically stacked way, but for equations one typically needs a more horizontal array which someone avoids interrupting the main flow of text. Maybe my notion is too quioxitic to be worth pursuing, but if you have any ideas, please add them to the above cited talk page. TIA---CH (talk) 3 July 2005 06:27 (UTC)

I don't really like this particular example. Keeping an open mind for other examples. Also I don't like the definition text in the corner. If you want to define something you should use := or =: for absolute clarity. --MarSch 3 July 2005 13:25 (UTC)

Paul Erdős moved to Pál Erdős

What do people think about the recent move of Paul Erdős to Pál Erdős? Paul August July 3, 2005 04:14 (UTC)

In general, articles should be at the title most commonly used in English. See Wikipedia:Naming conventions (common names). The new title may be more "correct" in some sense, but it's not what most books have. Until "Pál Erdős" becomes the generally used form, I would rather stick with "Paul". Isomorphic 3 July 2005 06:15 (UTC)
I agree with Isomorphic, although I do think the English-language article should mention the Hungarian form of his name.---CH (talk) 3 July 2005 06:29 (UTC)
I've put a mention of the Hungarian form in the intro, and moved the article back to its original title. Isomorphic 3 July 2005 06:32 (UTC)

I can understand why Russian names are not at their original name, although they probably shold be, but I cannot understand this at all. What's worng with Pál? --MarSch 3 July 2005 13:37 (UTC)

See Isomorphic's response: the problem with Pál is that it is not used that often in English. -- Jitse Niesen (talk) 3 July 2005 14:58 (UTC)
I think the English name should be used. That's how I always encountered this guy in the English mathbooks. Same thing as with John von Neumann who orignally was Janos. Oleg Alexandrov 3 July 2005 15:38 (UTC)

Anyone who publishes scientific articles is urged to choose one name, and one name only, under which to publish, so as not to confuse readers and in order to make bibliographies easier to assemble. Under what name did Paul Erdos publish? Shouldn't the article be under the name he himself chose? -- linas 3 July 2005 15:46 (UTC)

I didn't even know John von Neumann is actually named Janos. How stupid is that. Or did he change his name upon becoming an American? --MarSch 3 July 2005 16:09 (UTC)

I took a quick search on MathSciNet. Everywhere I saw Paul. The only exception is

Surányi, J. Remembering Pál Erdös. Paul Erdös and his mathematics, I (Budapest, 1999), 47--49, Bolyai Soc. Math. Stud., 11, János Bolyai Math. Soc., Budapest, 2002. 01A70.

So, even the Hungarians call him Pál only to emphasize that he is their guy, while the formal name is Paul. Oleg Alexandrov 3 July 2005 16:17 (UTC)

Why do I prefer Isomorphic's criterion to Linas's criterion? I think biographies in en:wiki should be named according to the name English language readers are most likely to encounter, particularly in searching on the web. Usually, this will agree with the name the person went by in his own writings (such is the case with Paul Erdos), but there are exceptions, such as some Russian mathematicans whose names appeared in print in various German and French language journals with transliterations which would now be regarded as archaic, like Tschebycheff. So an article on Chebyshev should use the currently most popular spelling in English language sources, but should of course mention other forms of the name which a reader might encounter. Any questionable cases should probably be resolved by asking what choice of name is least likely to confuse the average Wikipedia reader. So for example, some modern transliterations of Chinese names or Russian names might actually be more confusing than using the most commonly encountered name. Case in point: you all probably know who Shing-Shen Chern was (if not see [13]), but the wiki biography is called Shiing-Shen Chern. I am told this is a more accurate transliteration, but it is neither what he most often went by nor the form of the name which English language readers are most likely to encounter in web searches.---CH (talk) 3 July 2005 20:26 (UTC)
P.S. An example of another common naming problem: Émile Picard went by Émile, not Charles, but his biography appears under his full name, which readers are unlikely to encounter except at the popular MacTutor Archive [14], which uses full names exclusively. This practice always makes me think of the quip that triple barrelled names always seem to denote either murderers (Lee Harvey Oswald) or philosophers (John Stuart Mill). ---CH (talk) 3 July 2005 20:45 (UTC)

Maths COTW: Manifold

As mentioned above, we are witnessing an attempt to revive the Mathematics Collaboration of the Week (which should probably be renamed to Collaboration of the Fortnight since it seems to run over two week periods). I am pleased that manifold was chosen to be the target of the collaboration and I'd like to invite all of you to contribute to this article. Note that we are currently rewriting the article at manifold/rewrite. Please put further comments on Talk:manifold/rewrite. -- Jitse Niesen (talk) 4 July 2005 13:26 (UTC)

Hierarchy in the math articles

What people think of the article tangent bundle having on top the notice that it is a subarticle of differentiable manifold? Or of the planned topological manifold article being thought as a subarticle of the manifold article? I find this terminology introduced by MarSch a bit unusual. It implies that some articles are subordinate to others.

Also, I am not a native speaker of English, but doesn't the phrase

Tangent bundle is a subarticle of differentiable manifold

imply the former is a chunck of text contained in the latter, rather than a standalone article is it is now? Oleg Alexandrov 4 July 2005 15:43 (UTC)

I am not a big fan of the hierarchy thing. It is only in very rare cases that I would approve. This is not one of them. I bet that the term "tangent bundle" is probably used in other areas of mathematics that have nothing to do with differentiable manifolds, or at least are only loosely analogous to them. I think algebraic geometry might be an example, but I'm not an expert. Perhaps someone else can expand on this. (Oleg: I'm not even sure if "subarticle" is a real english word :-) Dmharvey Talk 4 July 2005 20:06 (UTC)

With few exceptions, no article should be subordinate to any other article. I can imagine some kind of "subarticle of" relationship perhaps being useful, but I don't think it should be a hierarchical parent-child relationship. We would certainly want an article to possibly be a "subarticle of" more than one article, and perhaps even two articles to be "subarticles of" each other, both of which however run counter to the usual notion of "subness". In short I don't think it is probably a very good idea. Paul August July 4, 2005 21:06 (UTC)

The terminology is indeed confusing, but I like the idea of having a prominent link at the top of tangent bundle pointing to differential manifold. How about a phrase like "See differential manifold for more background." -- Jitse Niesen (talk) 4 July 2005 21:15 (UTC) (via edit conflict with Paul)
Definitely agree there should be such a prominent link. Dmharvey Talk 4 July 2005 21:17 (UTC)

Wikipedia is not heirarchal. If you start building linked lists and trees into the software through templates, you are breaking the design of Wikipedia. It has purposfully been designed NOT to be heirarchal. This discussion has been gone over many times allready in the past 4 years and there are rules against it. If you want to draw attention to another article, you do what every one else does: write it into the text of the article, explain why, and provide context for the reader.

Keep in mind, articles can be copied anywhere, in any format, including paper, it has to be assumed that the reader is not reading the article using software and a computer, and thus does not have access to links. Thats why Wikipedia style guidelines are the way they are, articles are self-contained units with no dependencies or heirarchies. Stbalbach 5 July 2005 03:11 (UTC)

Basically a differentiable manifold is a topological manifold, so there is a section of topological manifold about #differentiable manifolds. This section cannot contain all information on diff. manifolds so there exists now a full article on them (complete with intro and everything), with the most important parts in the section of top. manifolds. This is policy. For this situation were created the templates {main} and {seemain}. One to go in the section and one to go at the top of the corresponding article. Unfortunately the wording of these templates was identical and is still almost. Therefore nobody could knew which was which and they were used interchangeably. Consequently somebody listed them at tfd, because the seemed to be forks. Their creator SEWilco explained that they have different purposes. I voted to keep at first, but then I went and read their talk page descriptions and I found it very difficult to understand which was which. Basically because each uses main in a different meaning. Main as in has the most information and main as in is more general and thus has less information. So I started a discussion and proposed new templates with a clear distinction. These are {subartcleof} and {seesubarticle}. Their names are clear and their wording is clear. You may not like that wording though. The use of two such templates implies a acyclic graph structure. It is possible to have multiple subarticles and also to have multiple superarticles, just as it was with {main} and {seemain}. Stbalbach may rage against the {subarticle} templates, but the fact is that he uses the {main} versions which basically have the same purpose and also imply a hierarchical structure whether he realizes it or not. These templates are not intended to connect articles on the same level. If you want that then you need another template such as {siblingarticle} which does not exist yet. This is hardly an argument against {main} and {seemain} or {subarticle}s. So I can only understand all this by assuming you dislike the current wording. --MarSch 5 July 2005 10:45 (UTC)

Since the word subarticle seems to cause problems. What about two other templates

  • {details}: For more details on this topic, see the article {1}.
  • {background}: For more background on this topic, see the article {1}.

Please discuss at Wikipedia:Templates_for_Deletion#Other_wording --MarSch 5 July 2005 13:41 (UTC)

Just in case people have not noticed, {{Template:subarticleof}} is up for deletion at Wikipedia:Templates_for_Deletion#Template:Subarticleof. Oleg Alexandrov 6 July 2005 03:41 (UTC)
Paul: such multiple relationships are possible. Horizontal grouping cannot be done with these, you need another template for that. So those are not two arguments against this template.
Dmharvey: I don't understand why you do want the prominent link, but not the hierarchy. What is the difference?\
Oleg:What about subcategories? Are they somehow not standalone?
That's the very point of it. Categories were meant to replace any other form of hierarchical relationship. No need for more. Oleg Alexandrov 6 July 2005 15:23 (UTC)
Jitse, what do you mean by prefer written out in full? What is wrong with a template? Do you want local variation? --MarSch 6 July 2005 11:25 (UTC)
My problem with templates is that they are not transparent. If I see a template when I'm editing an article, it's not immediately obvious what it does. It's not a big problem, but I also think it's not a big gain to write it out all the time (use subst: if you are too lazy). I understand that this may lead to variation, but that is quite okay with me. But let me iterate that this is really a miinor issue for me. -- Jitse Niesen (talk) 6 July 2005 19:55 (UTC)
I want the prominent link because anybody looking up tangent bundle should realise that the idea comes from differential geometry. I don't want the hierarchy because tangent bundle may apply to settings other than differential geometry. As I said above, I'm not an expert, and I don't know much about these other settings. However, take a look at [15] on planetmath. Towards the bottom of the article, you'll see a discussion of how you define a "tangent bundle" over a scheme (mathematics), which is a pretty abstract version of tangent bundle, and has nothing to do with differential geometry. Dmharvey Talk 6 July 2005 12:56 (UTC)
I think sometimes the link is clear from context. Sometimes different wording should be used. I very much agree with Jitse (see Wikipedia:Templates_for_Deletion#Other_wording) that mindlessly slapping templates on articles illustrating its dependencies is not the way to go. Oleg Alexandrov 6 July 2005 15:23 (UTC)
Dmharvey, the link is the hierarchy. I guess you object to my calling it a hiereachy and using the word subarticle. But I can only guess, since you haven't explained yet. Do you like my proposed alternatives any better?
Oleg, there is nothing mindless about slapping a template on something. Mindless is not an argument. This is one relation that I would like to highlight and I don't see what would be gained by doing that in a different way each time. Saying templates are mindless implies you want all templates to go away.--MarSch 6 July 2005 15:38 (UTC)
Oh, and forgive me for forgetting, but I can't believe I have to say this yet again. There is nothing to prevent tangent bundle from having another link to scheme. --MarSch 6 July 2005 15:41 (UTC)
Hi again, there seem to be a lot of proposed alternatives floating around, and I'm not quite sure I understand what they are. The problem I see with having a message like "this is a subarticle of differentiable manifold" on the "tangent bundle" page is that you would then require also "this is a subarticle of scheme" and so on. It just seems unwieldy and unnecessary. My preference is to have an introduction on Tangent bundle which discusses the tangent bundle in relation to differentiable manifolds as the simplest and most important case, mentions the fact that tangent bundles have analogues in quite different settings (for example in schemes), and then the main article focusses on the differentiable manifold case, and perhaps later we have a section that expands on the various generalizations of the tangent bundle concept. (This discussion reminds me very much of the ongoing debate about Derivative, which is perhaps not a coincidence, given the close relationship between derivatives and tangent bundles :-) ) Personally I would be unable to write such an article because my knowledge of generalisations of tangent bundles is extremely limited.
I think the best reason to avoid "subarticles", "main articles" and so on, is that it introduces too much unnecessary rigidity into the structure of the whole encyclopaedia. You really can't predict what people will want to expand on later. Dmharvey Talk 6 July 2005 16:21 (UTC)

Mathematics Subprojects, Anyone?

I'd like to point out that there are already some projects which can be described as subprojects of this one, and to suggest some new ones:

  • listing key publications in the history of mathematics (actually, I think this one is a quixotic task),
  • adding suitable citations to all mathematics articles (I see this as much more painless and feasible, but encourage participants to try hard to add only really suitable citations to articles on topics for which they know the textbook literature),
  • themes of mathematics: examples include multiplicity of representations, levels of structure, local to global, classification, categorification, (all but the last two just came up in the manifold/rewrite discussion--- I'd say that manifold is a concept in mathematics, but classification theorem is a theme, and a big one),
  • classification theorems could be a category in itself, which would include for example Thurston's classification theorem and Bianchi groups,
  • actually, Bianchi group could itself be a category, since I for one believe that these guys are worthy of indidivual articles (which I plan to write), and similarly for other classifications (e.g. an article on H2 should be accessible in one click to someone searching for manifolds of constant curvature, sometimes called space forms).

The goal of the proposed themes of mathematics subproject could be to ensure that any reader who comes to the math pages here will be likely to encounter at least one of these "big ideas", and will be encouraged to read more about it. At present, many articles adequatley describe a concept but fail to point out that this concept exhibits certain themes, an oversight which I think should be systematically rectified. For some examples of how big ideas can be incorporated into articles, see my discussion in the talk page for the manifold/rewrite article.

Categorification seems to be a notion some mathematicians hate with a passion, but what I have in mind for the categorification subproject is something I expect we could all agree on: many articles describe concepts but fail to point out that they are examples of categorical notions, and these often arise from an attempt to capture in formal language some theme. So the categorification subproject could have two complementary goals:

  • ensuring that articles mention (probably near the end!) when a concept is an example of a (usually much more general!) concept in category theory, such as a pullback square,
  • ensuring that articles on concepts such as pullback square link to articles on important examples of pullback squares.

By the way, the article on Thurston's classification theorem should clarify the relation with uniformitization. It should probably cite the little book by Andrew Casson.

--CH (talk) 4 July 2005 20:41 (UTC)

I would say we don't have enough mathematicians (post-doctoral, say) to indulge in subprojects. What is a big deal for us is still getting the top-down view right: fill obvious gaps, list articles, categorise, add biographies, and generally pull things together so that reading the English Wikipedia on mathematics can constitute a liberal education on it. Charles Matthews 08:38, 13 July 2005 (UTC)

Puzzle articles on VfD

Several articles on puzzles such as burr puzzle, mechanical puzzle and packing problem are up for deletion in two mass listings on VfD here and here. —Blotwell 5 July 2005 00:31 (UTC)

Thanks, many of them listed aren't the crap that they are thought to be. --MarSch 5 July 2005 16:16 (UTC)
Yes I agree, I have voted to keep these. Paul August July 5, 2005 18:19 (UTC)

Templates for thought

In a magic country far far away, there lived four templates, explaining what math is all about. They were named "quantity", "space", "change", and "structure" (note that "quantity" is actually about numbers). Here they are in full glory.


Straight Line Steady.svg

I would like to generate some discussion on whether these templates are useful, whether they should be trimmed, or even eliminated, replaced by categories. Wonder what people think. Oleg Alexandrov 03:23, 13 July 2005 (UTC)

(From talk:Transcendental number, copied here by Oleg Alexandrov 03:23, 13 July 2005 (UTC))

While I agree that these templates are a bit weird and of dubious utility, I'm not sure I completely support their removal. I might, but I probably need more convincing. The fact that lots of other technical subjects seem to have similar templates means that removal from the math pages would damage the consistency of wikipedia across technical subjects, and I do think we should value some uniformity of format at this project. So what am I saying, either we have to delete all the templates or none of them? No, that's probably too severe.
How about this Oleg, can you imagine a mathematics template which we could agree may be useful? Maybe a much coarser template, and only a single one instead of four of them. And maybe not organized so bizarrely (structure, quantity, change, and space???? wtf!). I'd feel better if we still had one organizing template, to ensure consistency with the other technical subjects. -Lethe | Talk 17:31, July 11, 2005 (UTC)
I despise templates. I like categories. I can make only one argument in support of templates: if one is learning calculus or trigonometry for the first time, they are a handy tool for trying to cram a whole bunch of facts into your mind at the same time. But once you're no longer cramming for school ... no. They're ugly, they're inaccurate, they chew up space, they impart little knowledge. linas 04:58, 13 July 2005 (UTC)
Templates are unpopular, justly. I think we only need a few templates, and those for pedagogic purposes. So, no bi-complex numbers, for example. Charles Matthews 08:33, 13 July 2005 (UTC)
I prefer the simple "See Also" section at the bottom of an article. Dmharvey Talk 11:38, 13 July 2005 (UTC)

I nominated the templates {quantity} and {strucutre} which have a lot of articles and which are not very related, for deletion. See Wikipedia:Templates_for_deletion#Template:Quantity and Wikipedia:Templates_for_deletion#Template:Structure. Oleg Alexandrov 23:09, 14 July 2005 (UTC)

I recently saw for the first time the {{mathematics-footer}} template

in my opinion, that's all the template we need for mathematics for consistency. Right? -Lethe | Talk 03:32, July 16, 2005 (UTC)

Kill 'em all. -- Dominus 04:55, 16 July 2005 (UTC)

Well, I got embolded and nominated for deletion the other two of the four templates. See Wikipedia:Templates_for_deletion#Template:Change and Wikipedia:Templates_for_deletion#Template:Space. Oleg Alexandrov 06:43, 16 July 2005 (UTC)

Fwiw, see also {{mathematics}}. —msh210 00:22, 26 July 2005 (UTC)

Redirects on rfd

Recently I moved Infinite tree (graph theory) to Tree (set theory), because the trees in question don't have to be infinite and don't have much to do with graph-theoretic trees. For the same reasons I have proposed that the two redirects, infinite tree and infinite tree (graph theory), be deleted. --Trovatore 04:19, 13 July 2005 (UTC)

Infinity-Borel set

I'm having a great argument with myself on the above-named page, and it'd be great if one/some of y'all would come referee. --Trovatore 04:38, 15 July 2005 (UTC)

Think I've sorted it out now. Still welcome to come take a look, though. --Trovatore 02:25, 16 July 2005 (UTC)

In fact please do come look at it, particularly the Alternative definition section on the Talk page. Opinions solicited on which definition is clearer/better. --Trovatore 02:52, 16 July 2005 (UTC)

Template:Quantity and Template:Structure

Template:Quantity and Template:Structure have both been listed for deletion at Templates for deletion. I don't know enough about mathmatical topics to know how coherent the topics are in either template, so I am requesting that some editors with some math knowledge visit TFD and offer their input to the discussion. BlankVerse 07:25, 15 July 2005 (UTC)

H numbers

Hello. The article H numbers looks like original research to me. Article links to this web site [16]. Mathworld hasn't heard of H numbers and I can't find any relevant Google hits. Comments? Thanks for your help, Wile E. Heresiarch 08:32, 16 July 2005 (UTC)

It looks like patent nonsense to me. Dysprosia 08:37, 16 July 2005 (UTC)
Not nonsense, necessarily. One can define such an algebra, I guess. But prima facie it is OR, and the link page just confirms that. Charles Matthews 08:39, 16 July 2005 (UTC)
Perhaps I use the term a little too loosely -- it appears to have some rather naive reasoning anyway afaics. Regardless, should be VfD'd for original research, plus it looks like an attempt to legitimize this by having a link from the hnumbers website back to us, and is in a sense advertising. Dysprosia 08:44, 16 July 2005 (UTC)
I agree. It looks like original research to me. Paul August 12:03, July 16, 2005 (UTC)
I don't think I'd call it research, but anyway let's get it deleted. Markus Schmaus 12:19, 16 July 2005 (UTC)

absolute value article rewrite, RFC

I've just completed a major revision of the absolute value article. I've described the changes I've made here. I'd appreciate any comments/criticisms anyone might have. (Please respond here) And a good proofread would be greatly appreciated (my eyes now glaze over when I attempt to read it). Paul August 19:56, July 16, 2005 (UTC)

On my browser (Mozilla 1.7.8 running under Debian Sarge) the Wikipedia logo shows up in the article itself, on top of some of the text of the article. And the navigation, search and toolbox boxes are nowhere to be found. Something to do with this line?
[[Image:Absolute value.png|frame|The graph of the absolute value function for real numbers.]]
No, that line isn't the problem. I copied the article to my sandbox and deleted that line; problem's still there. --Trovatore 20:28, 16 July 2005 (UTC)
--Trovatore 20:14, 16 July 2005 (UTC)
I take back the "nowhere to be found" part--they show up at the very bottom of the article, in case that helps in debugging. --Trovatore 20:19, 16 July 2005 (UTC)
Just tried it in Konqueror -- same result.

Hmm I'll have a look. I forgot to say that any comments (specific to that article) should probably be directed to that talk page. Paul August 20:58, July 16, 2005 (UTC)

It works ok for me in Safari, Firefox And IE on a MacOS 10.3. Paul August 21:02, July 16, 2005 (UTC)

Same problem in Netscape 7.1 (Windows XP). I've noted it on the talk page for the article. --Trovatore 21:21, 16 July 2005 (UTC)

Works fine for me with Firefox, Mozilla, and Konqueror on Fedora Linux. Works equally well with Mozilla and Internet Explorer on MS Windows. Oleg Alexandrov 22:30, 16 July 2005 (UTC)
Yes, but that's after Paul's latest fix. Try this version: [17]. Clearly there's an issue with the Rf and Ent templates that someone needs to look at. --Trovatore 22:34, 16 July 2005 (UTC)
That one also works for me with Firefox on both Linux and Windows (did not try the other browsers now). Oleg Alexandrov 22:37, 16 July 2005 (UTC)
Well, Paul said Firefox worked. I don't have it to check. Doesn't work in Mozilla 1.7.8. --Trovatore 22:43, 16 July 2005 (UTC)
Ok I can see we are having a multipage discussion. My fault really. let's continue any future discussions at Talk:absolute value. I'm heading there now ... Paul August 22:47, July 16, 2005 (UTC)

Merging of Portal and Category

Has anybody noticed the new Category:Mathematics? --R.Koot 19:54, 17 July 2005 (UTC)

Nice job, visually. I'm a bit concerned, though, that the formalist view is presented in a way that might suggest it's the default. This may not have been the intent, but possibly should be addressed. --Trovatore 20:30, 17 July 2005 (UTC)

Actually, that bit used to be in the main mathematics article - now we have something more mushy, and I miss it. Charles Matthews 20:58, 17 July 2005 (UTC)

By the bye, it led me to an interesting discussion that I hadn't seen before, and I cast my "yes" votes on math being a science and emperical. See Talk:Mathematics#Is Mathematics a science? and Talk:Mathematics#Is Mathematics empirical?. --Trovatore 20:30, 17 July 2005 (UTC)

The big challenge is to keep the portal thing up to date. I myself am no big fan of a Wikiportal, whether stand alone or embedded in the category. Oleg Alexandrov 20:39, 17 July 2005 (UTC)
One of my two main objectives. See User_talk:DavidLevinson#Category Mathematics --R.Koot 21:45, 17 July 2005 (UTC)

I redirected Wikipedia:Wikiportal/Mathematics to Category:Mathematics now that the contents has been merged. I do agree that the latter is more visible, as there is a link to it from the main Wikipedia page. I also put a note on Wikipedia talk:Wikiportal/Mathematics saying that the math talk usually takes place on this page, Wikipedia talk:WikiProject Mathematics, and not there. I plan to put the same note on Category talk:Mathematics. Oleg Alexandrov 17:51, 18 July 2005 (UTC)

I've put Template:MathematicsCOTW on TfD as is superseded by Template:Wikiportal:Mathematics/Opentask]. --R.Koot 18:41, 18 July 2005 (UTC)

Definable number

The definable number article is in pretty bad shape. Whatever it is that the article is talking about, it makes some true and useful assertions about--but it's very unclear what it's talking about. See the talk page. --Trovatore 04:40, 19 July 2005 (UTC)

I've rewritten the page. See talk page for discussion. --Trovatore 05:15, 21 July 2005 (UTC)

BTW why isn't there a template for "math accuracy disputes" or "math articles needing attention" or some such? I put the {{accuracy}} tag on it and believe I'm completely justified--but that only puts it in the "Accuracy disputes" category, where it could wait forever for a mathematician to notice it. It would be nice to put it in a more specific needs-attention category. But then again I suppose that's part of what this page is for. --Trovatore 04:40, 19 July 2005 (UTC)

I decided to see, replaced {{accuracy}} with {{Math-accuracy}}, meant to hit Alt-P but hit Alt-S by mistake, got the red template link, and now it won't let me change it back. Something going on with the server?--Trovatore 05:03, 19 July 2005 (UTC)

OK, I think I'm done with it for now. Anyone here who knows about forcing is invited to check my proof that it's consistent with ZFC that there are only countably many OD reals (or better, find a reference). --Trovatore 03:10, 22 July 2005 (UTC)

Forgot to mention, the proof's not on the main page; it's on the talk page. --Trovatore 03:40, 22 July 2005 (UTC)

The article isn't perfect but at least it no longer gives the false impression that there's a univocal, mathematically well-understood notion of what it means to be a not-further-specified "definable" real. Unfortunately there are lots of pages that link to the page, and some of them do give that impression. Not sure what to do about that yet. --Trovatore 03:10, 22 July 2005 (UTC)


Anybody here heard of mnenta? It's the only contribution from some IP address, I cannot find it in MathSciNet or OED, and none of the 14 pages returned by Google is relevant, so unless somebody speaks up it will go to VfD. -- Jitse Niesen (talk) 19:39, 19 July 2005 (UTC)

Sounds like the sort of thing Clifford Pickover does; but I don't remember it specifically. Whether this should, if true, save it from VfD is another question. Septentrionalis 19:43, 19 July 2005 (UTC)

This is a dicdef at best without some relevance to the rest of mathematics; I say VFD. --Kinser 23:16, 19 July 2005 (UTC)

If someone knows Pickover well enough to e-mail him, I say go for it; maybe the article can be brought up to a level worth keeping. But if there's no serious, immediate prospect of improvement, I'll vote delete--the article as it stands is very uninformative. --Trovatore 23:52, 19 July 2005 (UTC)

Without a source, this is unverifiable and should be deleted. Paul August 03:47, July 20, 2005 (UTC)

Sounds like a mini-consensus. Jitse, why don't you put it on VfD and get the ball rolling? If the article has defenders, that'll concentrate their minds. --Trovatore 04:12, 20 July 2005 (UTC)

Went ahead and did it myself--hope you don't mind. --Trovatore 05:48, 21 July 2005 (UTC)

Puzzle VfD ... Its baaaack ...

The puzzle articles are under renewed attack.

I am concerned that these VfD's are being pushed by someone who has it in for puzzles. I am concerned that the people voting to delete never actually contribute to math or physics articles. In a moment of heated anger, were I to actually get that heated, then I would say that these people are anti-social vandals, and should be treated as such. But everyone knows I'm not a hot-head, right? linas 15:38, 20 July 2005 (UTC)

I think they all contain valid encyclopedic content. This is getting tiresome. Paul August 18:27, July 20, 2005 (UTC)
Yeah, -Ril- started some sort crusade Karl Scherer after he added 'spam' to some articles (which it barely was imho). --R.Koot 18:47, 20 July 2005 (UTC)

It should be noted that the articles are up for VFD as neologistic categorisation by Karl Scherer. Coupled with a distinct lack of non-categorisation content, existing only to fluff the categorisation enough to have an article for each class. The 100+ that have already been VFD'd were done so for predominantly the same reason.

Wikipedia is meant to be an encyclopedia, and not something to push your POV of how things should be categorised. Neither is it a collection of all information under the sun.~~~~ 22:10, 20 July 2005 (UTC)

You have to categorize articles one way or another. And I think Karl did a pretty good job. --R.Koot 22:19, 20 July 2005 (UTC)

Dotted box template up for deletion

I nominated Template:ImportantLabeledEquation up for deletion (this was a bit discussed above, see Wikipedia talk:WikiProject Mathematics#Dotted framebox around formulas). I myself think that dotted box looks ugly, and indenting should be enough to display a math equation or defintion. Oleg Alexandrov 18:43, 20 July 2005 (UTC)

The vote for deletion is at Wikipedia:Templates for deletion#Template:ImportantLabeledEquation. Oleg Alexandrov 18:44, 20 July 2005 (UTC)

Somewhere there one also can find Template:Calculus2 which is not necessary anymore, as it is just an old version of Template:Calculus. Oleg Alexandrov 00:40, 21 July 2005 (UTC)

Category:Integer sequences

(Moved to here from my talk page.) linas 17:17, 24 July 2005 (UTC)

I notice you recently recategorised quasiperfect number to 'integer sequences', but it seems odd to mark it as such given that no such numbers are known to exist. Do you see the categorisation as extending to any boolean property defined on integers (or maybe the naturals)? (I ask in all humility - it isn't clear to me whether the categorisation is appropriate or not.) Either way, it may also merit a clarification on Category::Integer_sequences. Hv 16:30, 24 July 2005 (UTC)

Hi Hv, If you know of a better category, please recategorize as appropriate. I was attempting to do a broad cleanup; the articles I placed in Category:Integer sequences I had found scattered about Category:Numbers, Category:Integers, Category:Number theory, Category:Number sequences, a few in some odd corners, and a few without any cats at all. Rather than having them scattered all about, I thought I'd at least pull them into one place. There may be a better way of organizing these, but I don't know of one/can't think of one at this time. If you have ideas, let me know. At any rate, quasiperfect number seemed a better fit there than elsewhere. linas 16:44, 24 July 2005 (UTC)
Hm, maybe Category:Divisor-related sequences, since there seems to be a dozen or so that can be loosely defined in this way, e.g. abundant number. linas 17:05, 24 July 2005 (UTC)
And then, there's Category:Totient-related sequences as well; e.g. highly cototient number. Is there a common name for these things? linas 17:13, 24 July 2005 (UTC)
Sequences can be finite, of course, but this category might be better named Category:Kinds of integer (or Types or Classes). Sequences should be kept for those where the order matters, like Fibonacci sequence or John Conway's Speak-and-say sequence. Septentrionalis 19:39, 24 July 2005 (UTC)
I agree. I saw Linas put primitive semiperfect number in Category:Integer sequences and I thought that it was very odd to call it a sequence, but I forgot to follow up on it. How about something like Category:Divisibility properties? -- Jitse Niesen (talk) 19:58, 24 July 2005 (UTC)
I'm not sure it's a divisibility property. How about Category:Properties of natural numbers? Or maybe a List of properties of natural numbers. --Trovatore 20:10, 24 July 2005 (UTC)

Something in the spirit of Category:Properties of natural numbers looks good to me. But can one shorten this in some way? Oleg Alexandrov 21:08, 24 July 2005 (UTC)

Category:Integer properties is shorter, if a bit looser. But presumably a description could explain that it is appropriate for properties defined over more restricted sets as well, such as naturals or positive integers. Hv 23:35, 24 July 2005 (UTC)
Or just make sure the articles somewhere say the property only applies to non-negative/positive integers. They probably should anyway. Septentrionalis 23:39, 24 July 2005 (UTC)
I'd prefer Category:Properties of integers. Somehow "integer properties" sounds like something that's an integer and at the same time a property. --Trovatore 00:16, 25 July 2005 (UTC)
I like Trovatore's suggestion. Oleg Alexandrov 01:33, 25 July 2005 (UTC)

Well, there are 75 articles in Category:Integer sequences; and it would be appropriate to introduce some subcategories, such as Category:Divisor-related numbers and Category:Totient-related numbers. The first seems to be a category over at mathworld, the second a neologism. I was fishing for a commonly-used, commonly-accepted name for these two cats. In all cases, I assume that the category will also contain "theorems pertaining to divisor-related numbers" and "properties of numbers that are in the divisor-related number category". I think we can add wording stating this explicitly,once we know the correct, commonly accepted cat names. linas 02:20, 25 July 2005 (UTC)

Personally I think "Divisor-related numbers" is horrible. Every number is divisor-related (for example, it has divisors, is a divisor of other numbers, etc). The things in the category are not numbers, but rather properties of numbers, and the name should reflect that. --Trovatore 01:43, 27 July 2005 (UTC)
And just in passing, I really wouldn't look to MathWorld, or PlanetMath either, as an example of how to do anything. --Trovatore 01:47, 27 July 2005 (UTC)
A category such as Category:Divisors of integers would be useful, and could be a subcategory of both the 'integer sequences' and 'number theory' categories. It would not just hold sequences, but I think people get a bit hypnotised by the sequence thing. Charles Matthews 10:11, 27 July 2005 (UTC)
Taken literally, which categories usually are, this would be coterminous with Category:Integer. I presume this is not what is meant; but what is meant? Septentrionalis 14:35, 27 July 2005 (UTC)
Quite a lot of number theory takes an integer n, looks at its set of divisors (a multiset, if you want) and then defines some function f(n) via that multiset. So, it's a substantial topic, and not really a tautologous thing either. Charles Matthews 14:43, 27 July 2005 (UTC)
Perfectly true (pun unintentional). And now I see what you mean. If the whole category becomes Category:Properties of integers, the subcat should be Category:Properties of divisors or even Category:Properties of divisors of integers (although I'd rather not go there). I will propose a move of the whole category now, to move that part of this discussion where it will do something. Septentrionalis 15:15, 27 July 2005 (UTC)
  • There is some misunderstanding; its about "numbers related through functions of the divisor function", and not whether or not numbers have divisors.linas 17:34, 27 July 2005 (UTC)
Which is precisely why "divisor-related numbers" is a bad name. If you have a category called "foo numbers", the individual articles should logically be about individual foo numbers. (So we shouldn't have any categories called "foo numbers".) (Maybe that was your point--I can't tell from the comment above and haven't bothered to trace through the history to see which comments are yours.) --Trovatore 06:20, 31 July 2005 (UTC)
There is a Category:Prime numbers which contains articles about related theorems. linas 23:53, 1 August 2005 (UTC)
  • I vote we keep the discussion here, instead of CfD, since almost no mathematicians hang out on CfD. I promise to make the changes myself, if we can build a reasonable consensus on what the naming should be. linas 17:34, 27 July 2005 (UTC)
    • Fine; CfD has been notified in case anyone there cares. The category talk page will refer them here. Septentrionalis 01:59, 2 August 2005 (UTC)


The article for this number is up for deletion at Wikipedia:Votes for deletion/3.14. Uncle G 02:01:35, 2005-07-25 (UTC)

User:Cruise (talk · contribs) has recently added a number of links to and A number of the pages on this site about social science topics (e.g. slavery) are a mix of facts and patent nonsense, and I have thus removed them. I have no idea about the quality of the math and statistics pages linked, e.g. at multiple correlation, but it would be a good idea if someone double checked them. - SimonP 03:20, July 25, 2005 (UTC)

the Multiple correlation link looks somewhat simple-minded but not utter bilge, at least at a glance. Septentrionalis 22:34, 25 July 2005 (UTC)


I have a disagreement over at cardinal number about using inline TeX which becomes HTML. I argue against it (that is, use HTML if TeX gives PNG), while the other opinion seems to be that if one really want HTML then one should set up the browser settings that way. Wonder what people think on this issue. Thanks. Oleg Alexandrov 22:40, 26 July 2005 (UTC)

The advantages to using markup like "<math>|X| \le |Y|</math>" rather than "|&nbsp;''X''&nbsp;| &le; |&nbsp;''Y''&nbsp;|" which in turn is automatically turned into HTML such as | <i>X</i> | ≤ | <i>Y</i> | are numerous, by writing formulae in an abstract markup language they can be turned into HTML, PNGs (and in the future MathML) on the fly rather than being restricted to just one of those options, it's not future proof, it's restrictive and it's bad for accessability to use html rather than the math module.
If you have a problem with how the math module is converting LaTeX into HTML please file a bug at . —Ævar Arnfjörð Bjarmason 22:59:06, 2005-07-26 (UTC)
This is an issue which comes up frequently and generates long discussions; see e.g. Wikipedia talk:WikiProject Mathematics/Archive4(TeX). The majority of mathematicians seem to prefer HTML, as documented on Wikipedia:How to write a Wikipedia article on mathematics.
My personal opinion is that given this situation, the author of an article gets to decide, which for cardinal number means that the HTML should not have been changed into <math> (if my cursory skim of the history is correct). However, I care so little about it that I won't even revert. I think the only permanent solution is technical, and that it would be more constructive to find out how to achieve a technical solution (of course, just filing bugs won't help much). -- Jitse Niesen (talk) 23:24, 26 July 2005 (UTC)
I found out in a discussion with Pmanderson that ℵ doesn't show up correctly for everyone. I think that by itself is a pretty good argument for LaTeX. Being able to use the aleph symbol inline is indispensible. --Trovatore 23:56, 26 July 2005 (UTC)
Right, if you have no choice then you use PNG. If you have a choice, you use HTML. Oleg Alexandrov 03:30, 27 July 2005 (UTC)
Thankfully the HTML-<math> renderer uses the proper fonts now, so it wouldn't be bad if <math> was used in articles (judiciously of course as it spontaneously springs to PNG if it is used a little too liberally) as it looks decent now, but I would suggest that PNG be reserved for inline as it has been. Dysprosia 12:13, 5 August 2005 (UTC)

Number articles up for deletion

The aforementioned articles are all up for deletion. Uncle G 02:18:02, 2005-07-27 (UTC)

I voted to delete them all. Paul August 03:35, July 27, 2005 (UTC)


I noticed that there is no Category:Symmetry. Should there be? Charles Matthews 10:13, 27 July 2005 (UTC)

I think it is a good idea. Here are a bunch of articles which could go there:

Axis of symmetry -- Broken symmetry -- Circular symmetry -- Freiling's axiom of symmetry -- Homological mirror symmetry -- Mirror symmetry -- P-symmetry -- Plane of symmetry -- Rotational symmetry -- Spacetime symmetries -- Spontaneous symmetry breaking -- Symmetry -- Symmetry group

(maybe not all of them). Oleg Alexandrov 15:47, 27 July 2005 (UTC)
Not Freiling's axiom of symmetry, I think. [In fact, if this and Symmetry group are removed, I see a good Category:Physical symmetry. 17:13, 27 July 2005 (UTC)] Septentrionalis 16:10, 27 July 2005 (UTC)
Hmm. Are you sure? This lumps together a bunch of otherwise unrelated topics. In physics, p-symmetry and spontaneous symmetry breaking are ... well, related, but in a subtle way. And these have little to do with some of the math concepts of symmetry ... If we create this cat, then we need to rethink the VfD for template:Numbers which lumped together a bunch of "unrelated" articles with the word "number" in the title. However, I think its lots of fun to have a list of all math articles with the word "number" in the title and it would be fun to have a similar list for symmetry. linas 17:05, 27 July 2005 (UTC)

I agree about not including Freiling's axiom of symmetry. Let us keep this geometric/physical. So for example, the article symmetry of second derivatives should not be there either. Oleg Alexandrov 17:24, 27 July 2005 (UTC)

And this asks an interesting question. If we adopt this cateogry as mathematical, putting it in the list of mathematics categories, should all the physics articles in category:symmetry be added to the list of mathematical topics? (For example, CPT symmetry.) Oleg Alexandrov 17:24, 27 July 2005 (UTC)
Not very harmful, I think. One can trust the physicists eventually to bend any mathematical concept to the breaking point. But if you think about rotational symmetry and circular symmetry, for example, it is a bit perverse to say that one is mathematics and the other isn't. Charles Matthews 05:42, 28 July 2005 (UTC)
Thanks Charles. Oleg Alexandrov 15:29, 28 July 2005 (UTC)

Proposal: rename Category:Math lists

The word Math (as opposed to Maths) is quite jarring for many Brits, and to me it feels somewhat too informal for a category title anyway. How about moving articles in this category to Category:Mathematical lists? This is a task which bots can perform fairly easily, I believe. Lupin 23:32, 27 July 2005 (UTC)

Fine with me. If agreed on the change, my bot can take care of it. (However, under no circumstances will I rename my bot from mathbot to mathsbot :) Oleg Alexandrov 00:13, 28 July 2005 (UTC)
Of course it should be renamed (the category, not the bot), see Category talk:Mathematics stubs for a precedent. -- Jitse Niesen (talk) 12:18, 28 July 2005 (UTC)

I think Category:Math lists better be renamed to Category:Mathematics lists, rather than Category:Mathematical lists. Any objections to that? :) Oleg Alexandrov 15:29, 28 July 2005 (UTC)

Picking nits, "Mathematics lists" could be interpreted by someone who knew nothing as being "Lists of various (kinds of) mathematics". I can't think of a meaning for "Mathematical lists" other than "lists of a mathematical nature". So I slightly prefer the latter. But I'm really not that bothered. Lupin 15:34, 28 July 2005 (UTC)

I see your point about mathematical instead of mathematics (and I agree). Lupin, I think you will need to submit a formal request at CfD for Category:Math lists to be deleted, and the articles moved to Category:Mathematical lists. I expect no problems with that, and then I can start the move. Oleg Alexandrov 22:06, 28 July 2005 (UTC)

I actually already moved the articles. Should we formally ask for the Category:Math lists to be deleted, or can an admin among us just quickly get rid of it? Oleg Alexandrov 02:41, 29 July 2005 (UTC)

blahtex: a LaTeX to MathML converter

Someone called "kate" once said to me:

the best way to get this implemented is to write the code :-)

I took her advice. Following a few weeks of down-and-dirty coding, I would like to announce blahtex version 0.1, a LaTeX to MathML converter designed specifically for Wikipedia (or more generally for the MediaWiki environment).

You can try it out interactively here. You can also see some samples extracted from Wikipedia here.

Important note: Your mileage may vary depending on OS/browser. I will get back to this in a moment. For now, I'll just say that your best bet is Mozilla/Firefox on Windows; if you're on a Mac then I'm afraid the world of MathML is rather inaccessible right now; if you're on Linux or another Unix then I really have no idea, I'm guessing Mozilla will be your best bet.

Before getting to more details, let's just check out this screenshot of blahtex plugged into MediaWiki:


Here's the wiki markup I used for this:

'''Archimedes''' was a [[Greek]] [[mathematician]] who is best known for the myriad mathematical
[[notation]]s that he invented, most of which are still in use today. His earliest work included
devising simple [[inline equation]]s such as <math>\sin x = \cos^2(y+t)</math> and
<math>x^2 + y^2 = -e^{-\theta}</math>. He pioneered the use of greek symbols such as
<math>\alpha</math> in English writing. While performing complicated calculations such as
<math>\sum_{i=1}^3 i^2 = 47</math>, he noticed that despite the baseline of the equation
lining up nicely with the surrounding text, the so-called [[displayed equation]]
: <math>\displayed\sum_{i=1}^3 i = 46, \qquad \textrm{unless} 46 \not= 47</math>
was probably better value. A similar effect occurred for integrals such as
<math>\int_0^1 \sin^2 x \, dx</math>. He marked this up using the kludgy "\displayed"
command, although he suspected that later and greater thinkers would come up with something
better. When he couldn't make up his mind he would write
: <math>\displayed F(x) = \begin{cases} \left\uparrow\frac{\partial^2 G}{\partial u \partial v}\right\}
& \textrm{if the sky was \bf blue}, \\ A_0 + \cdots + A_k & \textit{if Troy was on the attack.}
He also invented the polynomial rings <math>\mathbf{R}[x]</math>,
<math>\mathcal{C}[y]</math> and <math>\boldsymbol{\mathcal{C}[z]}</math>, and being
fluent in Chinese he was comfortable writing things like
:<math>\displayed 钱 = \sqrt{不好},</math>
although historians have debated whether his Chinese really was all that good.

How did I get this screenshot? I installed MediaWiki on my laptop (an iBook G3), and fiddled around with a few bits of the code to change the MIME type etc, and redirected the math code so that it fed into blahtex instead of texvc. A rather ugly hack. It doesn't really work. I don't recommend it. But it's enough to get something like the image above. The browser was Mozilla running on a Windows XP machine.

Blahtex's main features

backwardly compatible with texvc

In other words, all the equations already present on Wikipedia won't break.

Hmmm. A big claim. Probably not entirely true. In any case, a proposition capable of empirical testing.

Here's how I tried to test it. First, I downloaded a database dump of the current content of the English Wikipedia, from (I got the file dated 14th July 2005. It's 3.4 GB uncompressed, 1GB compressed.) Then I wrote some code to suck out everything surrounded by <math> tags. After throwing out some junk caused by people enclosing <math> tags inside nowiki tags :-), and discarding duplicates, we are left with 50193 distinct equations (71561 including duplicates; we lost about 80 "equations" as junk). If you want to play with them, you can get the full list here, one line for each equation. I set my poor laptop the task of running texvc on all 50193 equations, which took about nine hours. (About 1800 of them failed to work with texvc; casual inspection suggests these are things in people's personal sandboxes, and markup being discussed on talk pages.) Then I ran blahtex on all the equations as well (under ten minutes :-)). Actually I did this several times during development, to gauge progess.

For ease of comparison, I have collected the result together here (36 MB). Uncompress it and load up "index.xml" in your browser. You'll find the entire corpus of English Wikipedia equations, divided up pseudo-randomly into 256 pages (each containing about 200 equations), with the LaTeX, PNG output from texvc, and MathML output side-by-side for handy comparison. As mentioned earlier, I've put one sample page up on the web here.

(Warning: there are about 50000 small files in there, so if your filesystem is anything like the one on my mac, it could take up to 200 MB of hard drive space, even though there's only about 100 MB of data.)

So you can have a look yourself to see what blahtex's strengths and weaknesses are.

I should mention that I studied portions of the texvc code quite carefully to work out exactly what it was doing, and which LaTeX commands it accepts.

displayed and inline equations

Blahtex has command line options for choosing either inline equations (for use in running text) or displayed equations.

In my opinion, Wikipedia's greatest math rendering weakeness at the moment is the inability to do inline equations well. You can do simple stuff with HTML (although it renders inconsistenly with the displayed PNGs), and you can sure try to do PNGs inline, but they look pretty awful. In contrast, one of MathML's wonderful features is that it automatically lines up baselines and fonts with the surrounding text.

As you can see from the markup I gave above, I used the "\displayed" command to get displayed mode. This is just a temporary fix because I don't know enough about MediaWiki internals to make up another math tag (e.g. <mth>, or something like that). If blahtex is ever plugged into MediaWiki on a real site, I don't expect "\displayed" to be used.

You might point out that the font sizes don't match properly in the screenshot above, but I'm pretty sure this is more a result of my complete ignorance about CSS and stylesheets and MediaWiki internals, rather than any fault in MathML or the browser's rendering. As soon as someone who understands these things gets involved, the font size matching problem will go away.

unicode happy

As you can also see from the screenshot, blahtex is quite happy to accept Unicode characters. Try typing some chinese characters into the interactive form, either in math mode or inside text blocks (like \textrm). I'm sure that our friends at the non-English Wikipedias will find this very pleasant. Since MathML is based on XML, which in turn uses Unicode, it seems a bit silly not to support it.

Blahtex accepts input in UTF-8, and output is pure ASCII, but all internals are done with wide 32-bit characters, so it should be trivial to implement different input/output encodings if necessary.


I will be releasing the code under the GNU GPL, probably in the next week or so. I just need to remove various profanities from the code and generally clean it up. Stay tuned.

written in C++

Except for a yacc parser, it's all written in C++, with a healthy dose of STL. Probably C++ isn't the best choice of language from a technical point of view, but it has the advantage that I know it, and so do lots of other people. I think this will encourage collaborative hacking in a way that is not possible for texvc, which is written in OCaml, which not many people know.

Browser compatibility issues

So far all is well and good. Now we come to the hard stuff.

There are actually two completely separate questions concerning browser compatibility.

The first question is: how does the browser know that it should be trying to translate MathML tags? In an ideal world, the following would happen. Joe loads up a Wikipedia page with equations on it. If he's running Mozilla or Firefox, everything just works. If he's running internet explorer and has MathPlayer installed, then everything just works. If he doesn't have MathPlayer installed, he gets a dialog box telling him that he should install MathPlayer; if he chooses not to, he gets the next best alternative (e.g. PNGs). If he's running a completely MathML-unaware browser (like Safari), then he should just get the PNGs again (perhaps with a message telling him to get a different browser!!)

I don't know how to make this happen. For various technical reasons that I don't understand very well, it seems like a very difficult problem. I will leave this to the experts to sort out.

The second question is: assuming our browser does understand MathML and knows that it should be doing so, how does its rendering look? Does it render things "correctly"? Do different browsers give different renderings?

Let me summarise my current understanding of the situation here. Overall, I think the best browser I've played with is Mozilla/Firefox on Windows. It does have a bunch of bugs (which I will say more about on another day), but it does give the best overall effect. You'll notice that there is a radio button for "Mozilla tweaks" on the interactive site. This activates a bunch of tweaks to the output to compensate for some of Mozilla's bugs. Almost all of my testing has been on Windows Mozilla. MathPlayer for Internet Explorer is occasionally competitive, but its pixelation doesn't get corrected by XP, which is a major disadvantage, and sometimes it does some really weird stuff with spacing.

(NB: if you're on Windows and your equations look pixelated in Mozilla, you might want to try turning on ClearType. On XP, go right-click on desktop, then Properties, then Appearance, then Effects, then "Smooth edges of screen fonts" should be set to "ClearType".)

Sadly, on the Mac, you don't really have anything very good. Mozilla's support got broken a few versions ago. I'm not sure why they're taking so long to fix it. You could try running an old version (I think 1.3 is ok), but it doesn't look that great. Despite being a big mac fan, I concede that currently Windows kills the Mac in this department — you have no idea how hard it was for me to admit that :-)

As for other OSes, I'm pretty ignorant. Maybe someone else can report on the situation.

You could also try Amaya. It's a bit frustrating to work with (the mac version anyway), but sometimes helpful for debugging.

What to do now

I need your help. Play with blahtex and help me find and squish all those evil bugs.

Of course it would be fantastic if a MediaWiki developer knows how to plug blahtex into MediaWiki (at least the "MathML - experimental" option). Drop me a line if that's you.

I am going to run a blahtex development page at Probably the best place to continue this discussion is over there. In particular you can report bugs there.

now I'm off to bed

Goodnight guys and gals, I hope you enjoy playing with blahtex.

Dmharvey Talk 02:17, 28 July 2005 (UTC)


"If he doesn't have MathPlayer installed, he gets a dialog box telling him that he should install MathPlayer"

He gets a note on the top of the page that it would look better with Mathplayer, but it displays PNGs for now, letting him decide that he wants to install it when he gets around to it. :-)
Otherwise, very very cool.
I don't know much about mathML, but is it possible that little spacing issues could be from your code? Or is that just the browser's interpretation of the mathML? Specifically,
Moved to m:Blahtex/Bugs and feature requests
(HTML id tags would be helpful.) :-) - Omegatron 05:51, July 28, 2005 (UTC)
Hi Omegatron, thanks for your interest. I'd appreciate it if you could list the bugs on the page I mentioned at Right now I want to concentrate on getting the source to a level appropriate for release. I'll come back to those bugs in a little while. Dmharvey Talk 12:05, 28 July 2005 (UTC)

Very promising. Almost all formulas are understandable in my browser at work (Firefox 1.0 on Linux with Fedora Core release 2), though the spacing is often wrong; almost certainly the browser fault. Re 99d1d9133a0a5551e047a9560783aedc, there is a special latex code which should have been used, I think \ll, so it's not blahtex's fault. I hope dmharvey forgives me for saying that my personal opinion is that translating latex to mathml is the easy part and there is a lot that needs to be done, but as I said, it's a very promising start. I poked a bit around in the mediawiki code lately, going through some of the texmf bugs, and I'd be quite willing to lend a hand (within my time constraints, of course). -- Jitse Niesen (talk) 12:11, 28 July 2005 (UTC)

Yes, I forgive you :-). I agree it's probably the easy part, but not quite as easy as I had thought it would be several weeks ago when I started trying to write the code. :-) There are of course other translators out there, but in my opinion they have a lot of weaknesses, and I hope that eventually blahtex will be better. Anyway, maybe having a working translator will spur other people on to fix the MediaWiki end of things. Your assistance is appreciated. Dmharvey Talk 12:35, 28 July 2005 (UTC)
I don't understand why it's difficult. They already have rudimentary mathml output in the preferences, and blahtex looks like it works for everything. So isn't it just a matter of swapping blahtex in place of the older experiment? Could still leave the "experimental" tag on it, but it would be a better experimental. (And I'd start using it all the time.) - Omegatron 23:10, July 28, 2005 (UTC)
The problem is that your browser probably won't know that it's supposed to interpret the MathML as MathML unless the server sends out some additional information. You should try splicing some of blahtex's output into a page with wikipedia's standard headers and see if that works. I suspect it won't, although I haven't tried it myself. Maybe if you save it as a file with a xhtml extension, and fiddle with the file headers then that might work, or something like that. (btw, "rudimentary" means: it can handle equations as complicated as "x+2" but not as complicated as "x^2" :-)) Dmharvey Talk 16:38, 30 July 2005 (UTC)
Yes, I know; I've played with it. But if they can already get my browser to display mathML for , and a Tex-to-mathML converter has been written, why can't they combine the two? It sounds like the rudimentary mathML support already does all the "hard stuff" like MIME or XHTML or whatever other strings of capital letters. - Omegatron 00:48, August 4, 2005 (UTC)
Your browser (probably) doesn't really display the MathML for .
For example, I often use Safari, which doesn't know anything about MathML. The MathML code for "x+2" is <mi>x</mi><mo>+</mo><mn>2</mn>. So safari just ignores the tags like <mi> and just prints the conents inside the tags, which turns out to look ok (i.e. looks like "x+2"). But for anything more complicated it's useless. For example to do something like "x^2" it sees <msup><mi>x</mi><mn>2</mn></msup> and it just prints something like "x2".
Now here's the thing. Even a browser like Mozilla, which knows about MathML, will just print "x2", UNLESS you put a whole bunch of headers at the beginning of the page, which Wikipedia doesn't currently do. So, although it would be very easy to simply plug blahtex into the mediawiki software to do the conversion, it would presently be useless, because no-one would be able to see the MathML output. (Unless they manually changed the headers on every page they downloaded, which is ridiculous). Until Wikipedia is able to send out the right headers, or unless there is some other way to coax everyone's browsers into interpreting the MathML, there isn't any point in just "plugging it in". Dmharvey Talk 10:55, 4 August 2005 (UTC)
Aha. Well, is it really that hard to plug in the appropriate headers? Is it a server-side MIME kind of thing as well or is it something that could be added with a clever user.js or greasemonkey script? If the current experimental mathML can't add the headers either, then what's the harm in plugging in the new converter? - Omegatron 17:08, August 4, 2005 (UTC)

n-th versus nth

There are quite a few articles that use "n-th", "n-th", and/or "nth" (similarly for "ith", etc). All of the literature I checked uses "nth" (and occasionally "nth"). The only justification for "-th" that I can see today is if you don't have italics available, such as in a newsgroup. Based on the articles I've seen, I think that "nth" is more common in Wikipedia than "n-th" and "n-th", but I didn't do a formal count.

I think the standard style should be "nth". Bubba73 22:14, July 28, 2005 (UTC)

I prefer nth; but I could understand an editor deciding that it was unclear. A standard, but not a mandatory one?

But then, I spent today watching the anti-Communist revert wars and the &^$%&$ AD/CE revert wars, so I'm a little more laissez-faire than usual. Septentrionalis 22:40, 28 July 2005 (UTC)

I prefer n-th. I guess it was my edits which brought Bubba73 in here. If many people say they like nth, I will obey. :) Oleg Alexandrov 23:07, 28 July 2005 (UTC)
Should be nth. Bit of a pain to type, but if you have to use it in a lot of places, copy and paste (or write nth and do a global change). --Trovatore 14:36, 29 July 2005 (UTC)
Would be nice if we had a wiki shortcut for super and subscripts. I've been using T_{E}X (=TEX) markup in my greasemonkey scripts, although that might be confusing when alongside the same thing inside math tags?
Also things like 220+-5% becomes 220±5%, ==> becomes ⇒, 100degC becomes 100°C, and so on. - Omegatron 16:11, July 29, 2005 (UTC)
My personal preference is for nth too, and that is sometimes used in the literature. However, nth is much more common in the literature.
Another argument in favor of nth is that TeX has a function "\nth{<number>}", which makes 1st, 2nd, nth, etc, although it isn't implemented in WP. Furthermore, TeX interprets "n-th" as "n - th". Since math formulas are rendered in TeX, I think we should use nth to be consistent. Bubba73 16:08, July 29, 2005 (UTC)

I think n-th is marginally easier to read. I think i-th, for example, is definitely easier to read than ith. I think (n − 1)th is not a sensible piece of notation, for example; and the sort of thing that shows we should mostly aim to be clear and readable. Charles Matthews 16:34, 29 July 2005 (UTC)

Well, (n − 1)th is just jarring to my ear; I prefer (n − 1)st. I can see the point that maybe it should be (n − 1)st or (n − 1)-st, to keep people from trying to evaluate it as an exponentiation (although the latter two choices could be, respectively, multiplication or subtraction). --Trovatore 16:39, 29 July 2005 (UTC)
That's a good argument against nth. nth and (n − 1)th look the best to me, so far, though it seems there's a better solution for n-1 out there somewhere. - Omegatron 16:46, July 29, 2005 (UTC)
But in my experience nobody (or almost nobody) actually says "en minus oneth". We say "en minus first". Conflict between euphony and logic, perhaps--in this situation I vote for euphony. --Trovatore 16:50, 29 July 2005 (UTC)
Quoting Charles, "I think n-th is marginally easier to read. I think i-th, for example, is definitely easier to read than ith" (ditto for i). Readability is the reason I prefer nth over nth. But nth seems to be almost universal in the literature and I haven't found n-th in the literature. My feeling is that WP should be more like the literature in style than that of newsgroups and email. Bubba73 17:50, July 30, 2005 (UTC)


Wikipedia:Votes_for_deletion/Log/2005_July_29#Arc_Sine --R.Koot 14:24, 29 July 2005 (UTC)

Law of information

Is this article salvagable; does it even make sense? Law of information --R.Koot 15:18, 31 July 2005 (UTC)

I couldn't make any sense out of it. When I searched the internet I found a discussion on a wiki about evolution. Markus Schmaus 17:11, 31 July 2005 (UTC)
I put it on VFD here. Samohyl Jan 17:15, 31 July 2005 (UTC)

Aug 2005


I find Other_names_of_large_numbers a rather dubious article. Google will only find a lot of the names here inside this article. --R.Koot 00:02, 1 August 2005 (UTC)

hmm, it does seem pretty arbitrary --MarSch 17:57, 14 August 2005 (UTC)
I concur -- Arthur Rubin 22:13, 16 August 2005 (UTC)

meta: help formulae

Has anyone else noticed what's happened at Someone has added a whole bunch of stuff which might be reasonable but I don't think it's the right place for it. It's certainly not what people should see when they go looking for help on TeX markup. I'm not really sure where it should go though. Dmharvey Talk 20:50, 1 August 2005 (UTC)

You might have noticed that I moved it to the talk page. The suggestions contain a lot of tweak factors, which are probably very specific to the browser and configuration. They are totally out of place at meta:Help:Formula and to be honest, if he can't be bothered to put them in the right place, neither can I. -- Jitse Niesen (talk) 17:00, 4 August 2005 (UTC)
I agree that they don't belong there at all. I think that was the point, though. Wanted them to be seen. Who's in charge of TeX markup, anyway? - Omegatron 17:05, August 4, 2005 (UTC)
The m:Developers are in charge of the software and hence also of the TeX markup (no surprise here). As far as I can see, there has been very little work done on it in the past two years, so I guess nobody is taking responsibility for the TeX markup specifically. That's why I'm pretty confident that just putting some comment on m:Help:Formula will anger people but not yield any improvements. -- Jitse Niesen (talk) 17:22, 4 August 2005 (UTC)
So no one in particular? Just kind of this thing that's there but no one ever touches or has anything to do with? - Omegatron 17:55, August 4, 2005 (UTC)

E (mathematical constant) moved to Euler's number

Ed Poor has moved E (mathematical constant) to Euler's number. Is everyone ok with that? I have no strong feelings either way, but the move has created a lot redirects which should be fixed (especially the double redirects). I don't know as yet if Ed intends to to do that. I'd be willing to help with the redirects, but i want to be assured that we have a consensus for the name change first. Please respond on Talk:Euler's number. Thanks, Paul August 19:55, August 2, 2005 (UTC)

Why should it be moved? I think I'll move it right back. Charles Matthews 20:01, 2 August 2005 (UTC)
No, I'm not happy with the move. It is rarely called Euler's number, I think. Bubba73 20:06, August 2, 2005 (UTC)
Good move. Leave it at Euler's number. - Omegatron 20:56, August 2, 2005 (UTC)

I think it would be best if everyone responded at Talk:Euler's number. Thanks Paul August 21:08, August 2, 2005 (UTC)

blahtex version 0.2 released

Blahtex is a new LaTeX to MathML converter designed specifically for MediaWiki.

More information is available at m:Blahtex.

At the blahtex download page may be found an interactive demo, samples of equations from Wikipedia, and the source code.

I invite everyone to participate in the discussion on how on earth to make MathML work in MediaWiki.

This message will be cross-posted on Wikipedia:Village pump (technical) and on the Wikitech-l mailing list (as soon as I figure out how it works).

Cheers Dmharvey Talk 13:37, 3 August 2005 (UTC)

Deletion of VfD

This isn't strictly an issue for this project, but I thought it was about such a fundamental part of Wikipedia that it should be widely publicized. It concerns the Vfd process (and as it turns out this page has been involved in several VfDs recently). There has been considerable recent discussion about possibly eliminating VfD see:

Paul August 15:19, August 3, 2005 (UTC)

Ongoing discussion at Wikipedia:Deletion reform and its subpages; my proposal is on Wikipedia:Deletion reform/Proposals/Speedy redirect Septentrionalis 01:29, 24 August 2005 (UTC)

Inline PNG formulas - a poll requested

There was a discussion right above about PNG-fied TeX vs HTML. It looks to me that the arguments for inline PNGs there were the same as in Wikipedia talk:WikiProject Mathematics/Archive4(TeX), but that the consensus nevertheless seemed to be that HTML is preferred to PNG.

However, the issue does not seem to die out, with some kind of silly revert war going on at cardinal number. I would like to see an informal poll to figure out what people think and if there is some consensus about it; and whether the issue is that important at all. I for one prefer HTML formulas inline if the TeX formulas become PNG images, unless HTML is unable to render the formulas correctly. Oleg Alexandrov 15:27, 3 August 2005 (UTC)

I've gone both ways on this. At first I put equations in as HTML if they were simple enough and used TeX for the more complicated stuff. However, it didn't look good to me to have some equations in one and some in the other, since they look so different. Secondly, in some fonts at least (including the one I use) the HTML Greek letters are not very close to the way I'm used to seeing them. Therefore, if some of the equations on a page were in TeX I want to do all of them in TeX. A drawback if TeX is that the characters are thin and not of uniform thickness, at least on my system. Bubba73 15:45, August 3, 2005 (UTC)
*sigh* — if only MathML was working, we could leave this debate behind.... (hint hint see above :-) Dmharvey Talk 15:52, 3 August 2005 (UTC)
Yes we know that MathML will cure all the ills. :) But it is at least 5 years away I would say. What is your position on inline PNGs in the meantime? Oleg Alexandrov 15:35, 4 August 2005 (UTC)
Haven't we been through this?
I can see both. Ideally we would use math tags for everything, and the inline PNGs and HTML and mathML generated from that code would look good no matter what. See m:Help_talk:Formula#Maynard_Handley.27s_suggestions for more about inline TeX tweaks, including appropriately-sized PNGs that resize along with text, etc. - Omegatron 15:41, August 4, 2005 (UTC)
Oleg, you're much more pragmatic than me :-) My position is: both inline PNGs and HTML look awful, but I am forced to concede that inline PNGs are worse. Therefore, in the current software environment, I think inline PNGs should be forbidden under all circumstances. As displayed equations, they are fine (if a little rough around the edges). I also think that inline HTML should be avoided if at all practical. Such equations should be made displayed if at all possible. In other words, I really don't like any of the options currently available for inline equations.
In response to some other points: (1) I'm not sure exactly what you're referring to when you saying that MathML is five years away. There are browsers out there that do a half-decent job. (Perhaps not decent, but half-decent anyway.) Besides, there are moves afoot. For example, the Stix fonts project is supposed to reach a major milestone later this year. (2) I'm concerned about the portability of Maynard Handley's ideas. I would like to see them up and running on a test wiki, so that I can try them out in a few browsers. Dmharvey Talk 16:10, 4 August 2005 (UTC)
In response to (1) and (2). What matters is when Microsoft's Internet Explorer will have default and goood MathML support. And I doubt that will happen soon. Oleg Alexandrov 22:13, 4 August 2005 (UTC)
I agree that IE won't have default MathML support soon (if ever). That's a shame. I also agree that the current plugin support (i.e. MathPlayer) leaves a lot to be desired. However, I don't think requiring a plugin is necessarily a bad thing in itself. For example, lots of people view PDFs in their browser, even though browsers generally don't have default support. (Correct me if I'm wrong about this.) There is some mechanism that lets the browser inform you when you need an appropriate plugin for something.
Yes you are right. :) So let us hope MathPlayer will work soon, and work not only for IE. Oleg Alexandrov 23:47, 5 August 2005 (UTC)
May I add that my position on inline PNG would change drastically if Wikipedia had MathML support enabled. If MathML was there and working, I would *encourage* people to do inline equations in <math> tags, and hope that this encourages people viewing those pages to switch to a better (!) browser. Dmharvey Talk 22:32, 4 August 2005 (UTC)

Separated from other text, I think TeX looks a lot better than HTML. However it's use inline is problematic. I usually try to avoid inline TeX, and I think there has been a consensus for this view. But to me it is also problematic to mix inline HTML with non-inline TeX, so sometimes when I want to use non-inline TeX, I also sometimes use inline TeX (for example for variable names, see absolute value). I would hate to see a hard and fast "rule" about this. Paul August 16:39, August 4, 2005 (UTC)

Agree about not wanting a hard and fast rule about it. But why would one use as in cardinal number the PNG instead of simply the html {1, 2, 3, ...}? Oleg Alexandrov 22:13, 4 August 2005 (UTC)
I agree that doesn't make a lot of sense. Paul August 02:51, August 5, 2005 (UTC)

Please see my comments on this issue at: Wikipedia_talk:How_to_write_a_Wikipedia_article_on_Mathematics#Too_much_HTML.3F. - Gauge 03:48, 21 August 2005 (UTC)

The blind, with screen reading software and with some kinds of HTML enabled software, have some hope of making sense of the page if HTML us used. Unless appropriate "alt=" attributes are required, they have no hope with PNG. Nahaj 02:35:26, 2005-09-08 (UTC)

If you would have checked yourself, the TeX in math tags is in the alt text. Dysprosia 02:41, 8 September 2005 (UTC)
The section is PNG formulas, and I understood the question to be HTML or PNG. Since my browser doesn't speak TeX, I'll guess you are referring to a PNG produced from the math tags? And I give, how is it that you expected me to tell PNG from a PNG produced from the tags so that I would have noticed this? Nahaj 02:51:08, 2005-09-08 (UTC)
I think you are misunderstanding how PNG formulae are generated. The formulae images are not manually created, users do not upload regular images of formulae. Formulas are written in the TeX language and are placed inside <math> tags. If the formula is very simple, the TeX representation of the formula is converted into HTML and displayed. Otherwise, if it is complicated, the TeX representation of the formula is converted into a PNG image and is displayed. The alt text of the PNG image is the TeX representation of the formula. For example, the PNG formula will have "S_{\mathbf{p}}(\mathbf{a})=\alpha\mathbf{v}_1+\beta\mathbf{v}_2" as the alt text. So the issue of 'appropriate "alt=" tags' is responded to, and thus some provisions at least are made for accessibility.
If you would have investigated this issue yourself, by either playing around in the sandbox, or having a look how some mathematics articles are typeset, and viewing the alt text of PNG formulae, you would have found out all this yourself.Dysprosia 10:40, 8 September 2005 (UTC)

Ten thousand articles waiting to be written ...

Looking for something to do? WikiProject Missing encyclopedic articles has made a list of missing science topics, containing articles on Weisstein's MathWorld that have no corresponding Wikipedia article. There are more than ten thousand entries (but a considerable number is due to different capitalization conventions), including the intriguing Algebra of Chinese Characters (unfortunately, it is just an empty article on MathWorld). On a side note, remember that there is also the PlanetMath exchange. -- Jitse Niesen (talk) 22:39, 3 August 2005 (UTC)

CiteSeer citations

I've created a template you can use for CiteSeer citations. If they ever change the URL again, only the template needs to be updated.

{{citeseer|View-based and modular Eigenspaces for face recognition|pentland94viewbased}}

{{citeseer|View-based and modular Eigenspaces for face recognition|pentland94viewbased}}

--R.Koot 22:28, 4 August 2005 (UTC)

I've also created one for links to MathWorld
{{mathworld|Register machines|RegisterMachine}}
Weisstein, Eric W. machines.html "RegisterMachine" Check |url= value (help). MathWorld. 

--R.Koot 03:33, 5 August 2005 (UTC)

The second one duplicates Template:MathWorld - Fredrik | talk 19:09, 6 August 2005 (UTC)
Did I say Template:Mathworld? I meant Template:ScienceWorld ofcourse. ;) --R.Koot 19:29, 6 August 2005 (UTC)

minus or negative infinity?

"linearly towards minus infinity" or "linearly towards negative infinity" or "linearly towards −∞"? - Omegatron 22:35, August 4, 2005 (UTC)

Negative infinity sounds right to my non-native speaker ear. Oleg Alexandrov 00:41, 5 August 2005 (UTC)
I think either of the first two are ok. The second sounds slightly more formal, but I once had a professor who couldn't stand people even saying "negative three", it was only "minus three" for him. Dmharvey Talk 00:56, 5 August 2005 (UTC)
I use minus infinity in speech, which sounds better, but that may only be so because it's closer to what it is in Dutch. I think I prefer negative infinity in writing, however. --R.Koot 01:02, 5 August 2005 (UTC)
I am a native speaker (UK English), and only ever use "minus", be it three or infinity. (I doubt I am Dmharvey's professor!). --stochata 21:32, 6 August 2005 (UTC)
To me, "negative three" sounds like the script of a Holywood B-grade. I'm a "minus 3" type of person. --Zero 13:43, 11 August 2005 (UTC)
IMO, they are different. minus infinity is a number, negative infinity is a place. -- SGBailey 22:04:53, 2005-09-08 (UTC)

Jitse's math news page

I don't know if you noticed, but Jitse Niesen made a bot to output the following page each day: User:Jitse_Niesen/goim. Here, listed are new math articles in the list of mathematical topics and list of mathematicians, new requests for math articles, fulfilled requests for math articles, articles in need of attention/on vfd, etc.

I believe this page should be a very useful resource for math articles editors (that is, us). I would suggest adopting this page to the project, that is, renaming it to Wikipedia:WikiProject Mathematics/recent changes or something, but I can't come up with a good name.

Any ideas of what else such a page can contain or what other things itchy bot writers like Jitse and me could do to improve the math wikiproject? Oleg Alexandrov 00:41, 5 August 2005 (UTC)

how about Wikipedia:WikiProject Mathematics/Current activity?
I've sometimes wondered whether it would be possible to write a "non-reciprocated link finder" script. If A links to B then in many cases B should link to A. Would be nice to find these more easily. But I can think of lots of reasons that it wouldn't really work. Dmharvey Talk 01:00, 5 August 2005 (UTC)
I could write such a script, and generate a list of pairs of math articles which have links going on only in one direction. Is that what you want? Oleg Alexandrov 23:47, 5 August 2005 (UTC)
I guess I would be interested to see that. My only reservation is that I expect there to be a very large number of links that we discover only really make sense in one direction, and that the links we are really interested in are actually hard to spot within such a list, and therefore that you'd be spending a lot of time writing a script that turns out not to be useful. So if your best guess is that it wouldn't be worth the effort, then don't bother. Otherwise, please go right ahead! (by the way, where is some information on how to write such robots? I might be interested in trying my hand one of these days.) Dmharvey Talk 23:51, 5 August 2005 (UTC)

To write the script would be very easy. It will not be a bot, rather a perl script analyzing all the math articles which I have stored locally on my machine (and I have all of the articles in the list of mathematical topics, updated daily). But I am not myself sure how helpful that would be. The total number of pairs would be in the tens of thousands. Maybe we should sleep on this idea for a while, and wonder if anything useful will come up. Oleg Alexandrov 00:05, 6 August 2005 (UTC)

I agree. Leave it for now. Dmharvey Talk 00:34, 6 August 2005 (UTC)
I moved User:Jitse_Niesen/goim to Wikipedia:WikiProject Mathematics/Current activity. Did you know that 2451 of the 8979 articles are (marked as) stubs? Rather depressing, really. -- Jitse Niesen (talk) 01:48, 6 August 2005 (UTC)
How did you find 8979 articles? I count 8227. Oleg Alexandrov 02:06, 6 August 2005 (UTC)
My first guess is that I include List of mathematicians and you do not. This gives me 746 links, and 8227 + 746 = 8973, which is close enough. I can send you the complete list if you want. -- Jitse Niesen (talk) 13:00, 6 August 2005 (UTC)

other languages

hi I'm just wondering if there are math(s) project pages like this in other languages? It sounds like a lot of people who hang around here actually are quite multilingual. I speak only English (and a pathetic amount of mandarin chinese). Dmharvey Talk 01:28, 5 August 2005 (UTC)

I could not find anything in Romanian or Russian. Oleg Alexandrov 02:22, 5 August 2005 (UTC)
Dutch: no mathematics project.
French: and (both not very active.) --R.Koot 02:40, 5 August 2005 (UTC)
Some are, inevitably, more active than others. And some of them were already linked together, I would never have been able to find the Japanese one myself. —Blotwell 13:08, 7 August 2005 (UTC)


Could an admin exchange Random Access Machine and Random access machine for me, please? Thanks, --R.Koot 02:40, 5 August 2005 (UTC)

Done Paul August 03:00, August 5, 2005 (UTC)

Another one: Mathematical reviews should go to Mathematical Reviews as it is the title of a journal, see Talk:Mathematical reviews. -- Jitse Niesen (talk) 12:25, 7 August 2005 (UTC)

Done Paul August 23:58, August 8, 2005 (UTC)

EXTRAPOLATION METHOD I would be grateful if the mathenaticians would be kind enough to look at my extrapolation method on to determine whether it is suitable for a link from Wikipedia. Copy of earlier E-mails with Wiki. are below. Edward G. Collier MBCS CITP

Unfortunately, it seems that one cannot paste E-mails into this area. My method was devised in 1987 and wasexplained in detail at a Royal Statistical Society special meeting on AIDS forecasting that year. It was briefly written up in the Jornal of that Society Vol 151 Part 1 1988 Although the professors, statisticians and epidemiologists present also explained their proposed methods, my simple (but not simplistic) mathod was the only one that ever produced any viable forecasts and is still being used today as can be seen from the web site. I also have used the method for several years in forecasting variant CJD in the UK. The SEAC sub-committee with responsibility for overseeing the progress of vCJD asked me to get the method published. However, the various mathematical bodies and journals that I approached declined to publish it as I had no references. As a retired engineer and not an academic, I had no way of finding appropriate references and in any case I had not referred to any as the idea came into my own head. I am sure that there are many people who could make use of the method - even in control engineering- if you can publicise it in the excellent Wikipedia. Thank you, Edward G. Collier

Peer review is not a perfect process, but Wikipedia is explicitly not supposed to be a way around it. See WP:NOR. --Trovatore 20:06, 13 September 2005 (UTC)

Project subpages

As some of you have noticed, partly in honor of Jitse's great new Current activity page — way to go Jitse! — I have created a new section on the project page to list and describe the various project subpages. I know they are all mentioned somewhere else on the page, but I thought it would be good to also list them together. At any rate that got me to thinking about these pages:

Should these also be subpages of this project? I could see some benefit to bringing these all under one banner so to speak. Paul August 17:38, August 6, 2005 (UTC)

Manual of Style (MoS)
I think we should not make them subpages, as these pages are not just about our project. So, our style manual, Wikipedia:How to write a Wikipedia article on Mathematics, might be better off standing on its own rather than
Wikipedia:WikiProject Mathematics/How to write a Wikipedia article on Mathematics.
I agree though that it is better to list some of those pages together, as there is quite a bit of duplication now on the project page, with things listed multiple times.
On a more general note, I would think the project page needs a bit of overhaul. Wonder what people think. Oleg Alexandrov 19:35, 6 August 2005 (UTC)
YES. Dmharvey Talk 12:29, 7 August 2005 (UTC)
On a related note, I think the name of the style manual, Wikipedia:How to write a Wikipedia article on Mathematics, is rather long and not so pretty. Maybe a renaming it to something else could be a good idea. Oleg Alexandrov 19:35, 6 August 2005 (UTC)
Actually, I think it could well be a subpage, like Wikipedia:WikiProject Mathematics/style. Or rename it to Wikipedia:Manual of Style (mathematics). Anyway, please do something, as I rarely type the title correctly at the first attempt. The other two pages should not become subpages: Wikipedia:Naming conventions (theorems) falls into the Wikipedia:Naming conventions (...) series and Wikipedia:Algorithms on Wikipedia is more computer science than mathematics. I also agree with Dmharvey above. -- Jitse Niesen (talk) 12:49, 7 August 2005 (UTC)
The shorter the better. :) I hope more opinions will come in as how to rename it, since it is an important document. Oleg Alexandrov 23:24, 7 August 2005 (UTC)
I agree that Wikipedia:Algorithms on Wikipedia should not be a project subpage. I hadn't really looked at it, just copied it from the project page —now I'm wondering if it belongs there either? Also I like either of the page titles Jitse suggested for the "How to …" page. Paul August 17:23, August 7, 2005 (UTC)
What about just Wikipedia:Mathematical writing or Wikipedia:Writing mathematics Dmharvey Talk 19:36, 8 August 2005 (UTC)
I think if we do not want to make it a subpage of this project, then it should probably be called Wikipedia:Manual of Style (mathematics) (per Jitse) since that would be consistent with other "Supplementary Manuals of Style" listed on Wikipedia:Manual of Style (see table to right.)

I agree with Paul and Jitse about naming it Wikipedia:Manual of Style (mathematics). By the way, I truly hope that the fat style template to the right will not make its way in our manual of style, it is just so long, and not so helpful (for example, why would we need in our manual of style a link to how to write China-related articles).

Oh, and we can make the shortcut WP:MSM point to the new location, to save some typing when referring to it. Oleg Alexandrov 20:30, 8 August 2005 (UTC)

Agree that Wikipedia:Manual of Style (mathematics) is good. Dmharvey Talk 01:51, 9 August 2005 (UTC)

Moved. Oleg Alexandrov 20:37, 9 August 2005 (UTC)

blahtex: now compiles on linux

Blahtex 0.2.1 has been released. It now compiles and runs on Linux thanks to Jitse Niesen.

Jitse has had some initial success with integrating blahtex into mediawiki: check it out.

Source code, online demo and samples here.

More info and bug reports at m:Blahtex.

Dmharvey Talk 01:53, 9 August 2005 (UTC)

Style: *-algebras

I was editing the *-algebra, B*-algebra, C*-algebra etc. pages for consistency of style and I noticed some pages had <sup> tags around the * in these expressions, thus giving (e.g.) C* rather than C*. This looks horrible (and increases leading) on my browser (Netscrape 7) and the majority of pages didn't have it, so I took out those I found. But I assume someone had a reason for putting them in: is there any browser for which this looks better? Our proposed style guide should address this one way or the other. (This is different from the superscripting issues discussed at Wikipedia:How to write a Wikipedia article on Mathematics already because it relies on the * character appearing superscripted by default.)

And while I'm here: our preferred spelling seems to be C*-algebra (not C* algebra, C-star algebra, C star algebra, etc.) The exception is that our page on *-algebras is currently at star-algebra. Is there any reason for this, for example, is it usually spelled this way in the literature? —Blotwell 04:58, 9 August 2005 (UTC)

mentions of categorical considerations

I wrote the section on morphisms in the article on projective spaces, and it occurred to me that while using the language of category theory to describe maps between projective spaces is extremely convenient, it might be off-putting for the undergrad who's never studied any category theory, and just wants to know about projective spaces. -Lethe | Talk 07:13, August 9, 2005 (UTC)

I agree. I don't think you can assume that the person reading about projective spaces knows about category theory. However, that doesn't mean you should throw out what you've done. I think the article needs both versions. (The baby one first.) Dmharvey Talk 11:03, 9 August 2005 (UTC)
I agree with Dmharvey, we can have our category theory and eat it too! (of course this come from someone who was a categorical topologist in a past life ;-) Paul August 19:55, August 9, 2005 (UTC)

But the thing is, for the example I'm thinking of, there aren't "two versions". I just say "in the category of ____ the morphisms are ____". there really isn't any category theory there that can be separated out. just some terminology that can be used or not used. -Lethe | Talk 22:07, August 9, 2005 (UTC)

Hmmm. A question: what title would you give the section if you chose to write it without categorical language? Would you still call it "morphisms"? Or something like "Projective linear transformations"? Are you worried that without the categorical language, it is difficult to motivate why these particular types of maps between projective spaces are important? Dmharvey Talk 22:16, 9 August 2005 (UTC)
It seems like only someone with category theory in mind would, immediately after describing a new mathematical construction, then describe maps between such constructions. I imagine that if I didn't have that language available, I also wouldn't have the mindset to take time out to describe the maps. So I guess it's probably OK this way? -Lethe | Talk 22:59, August 9, 2005 (UTC)
I'm not convinced. I think that for a reader interested in learning about projective spaces, but without the category theory background, it is still useful for them to hear the fact that the "right" kind of maps between such spaces are the projective linear ones, even if they don't quite have the context to understand what "right" means. Anyway, why is this the right category? What about algebraic maps between projective spaces? Dmharvey Talk 14:33, 10 August 2005 (UTC)

Sub and super markup feature request

I've requested that markup be added to simplify entering sub and superscript at Bug 3080. It's just TeX markup with mandatory brackets. I think it will clean up the markup and be a lot easier to type than HTML.


  • x^{3} → x3 (powers)
  • CO_{2} → CO2 (carbon dioxide symbol)
  • 1^{st} → 1st (ordinals)
  • ^{2}H_{2}O2H2O (isotopes)

I can't think of anything this would conflict with, can you? Vote for it if you like it. Suggest a different syntax if you don't. Other syntaxes were suggested, which I really don't like. - Omegatron 19:39, August 9, 2005 (UTC)

I am not really happy with new notation. You can just use math tags to do the same thing. Oleg Alexandrov 20:25, 9 August 2005 (UTC)
There are lots of uses for super and subscripts that aren't math, like or " place". There's really no need to type 17 characters to output 3. My markup is 6 characters; shorter and quicker and easier than both math and HTML markup. Math markup isn't appropriate for everything, and there's a lot of contention about whether it should be used inline with text at all.
And regardless of whether math markup is the way things should be done, HTML markup is the way things are done, in most cases (as in these featured mathematics articles: 1, 2).
This could save time and effort for those reading and writing the markup this way. - Omegatron 21:25, August 9, 2005 (UTC)
I agree that for things like CO2 and 1st it would be nice to have simpler markup. I disagree in the case of x^3, since this should have the semantics of a mathematical expression, but let's not go there, because that always seems to open up a can of worms :-). However, I'm quite uneasy about adding your modifications to the wiki markup. How are you going to handle the fact that there are probably quite a few ^ and _ and { and } characters hanging around in existing articles? Dmharvey Talk 22:25, 9 August 2005 (UTC)
It doesn't matter if there are ^, _, {, or } characters hanging around in the markup. It only matters if there are ^{ ... } or _{ ... } hanging around outside of math tags. If there are, I doubt there are many. The only article I can imagine having them is m:Help:Formula. There aren't even any in the TeX, ASCII art, or obfuscated code articles. (I checked!) I'm sure whoever would implement this also has the capability to search for the few that might be out there and surround them with nowiki tags first (or math tags, since they're probably mistakes). - Omegatron 23:46, August 9, 2005 (UTC)

FWIW, I like it, seems like a good idea. As to the stray-markup issue, what about articles that contain sample source code? I thought I saw an article that showed how to compute factorials in 18 different programming languages. linas 00:00, 10 August 2005 (UTC)

I have to admit it's starting to sound tempting. Have you suggested this to the people who work on chemistry articles? Dmharvey Talk 00:30, 10 August 2005 (UTC)
Yeah, I suggested it at Wikipedia:WikiProject Chemistry.  :-)
As for stray markup, just track it down and put <nowiki> tags around it before implementing the markup filters. I'm not sure how that works for preformatted text, though:
Testing testing 12 3<sup>4</sup> 5^{6} 7^{8}
Looks like it works for those, too. - Omegatron 02:47, August 10, 2005 (UTC)

AKS primality test cleanup

I've expanded the article with information about the algorithm itself, and some detail about the proof. I'm not happy with the look of the <math> sections though - this is my first attempt at a significant amount of mathematical markup - so some help in cleanup would be appreciated.

Eventually this article should probably include the full algorithm in programming terms (rather than only in mathematical terms), and describe the complete proof. But I need to learn a bit more about finite fields and group theory before I can hope to do that myself.

As far as I can see, the only markup forcing things to PNG are the use of \sqrt(r) and \equiv. Hv 13:39, 10 August 2005 (UTC)

Thanks. It's an important algorithm, which caused quite a stir when it appeared. I cleaned it up a bit. In particular, you should use \log for logarithms in <math> mode, and \ge instead of >= (incidentally, \ge and \le are other commands that force PNG, which is rather strange as they can be rendered rather easily in HTML). Look at my changes for details. Oh yes, if you reference articles like Lenstra 2002, they should also be put in the references. Cheers, Jitse Niesen (talk) 15:05, 10 August 2005 (UTC)
Thanks; I didn't know about \log, but I've noticed that I tend to miss the < and > operators; the references to more recent papers are not mine (though among my next tasks is to track those down and try to read them).
I'm not convinced I like the mix of <math> and inline HTML, but I accept there is no ideal solution at the moment - Bubba73's comments in the Inline PNG formulas discussion above resonated strongly with me. Hv 16:59, 10 August 2005 (UTC)
As I say in that discussion, I usually don't change PNG to HTML (though I do make the change sometimes when I don't think enough), but since you made the request, I thought it would be okay. Anyway, I changed it back. I hope you don't mind my changing the \forall in text. Sorry about assuming that you put the references in there; I should have checked that. -- Jitse Niesen (talk) 17:20, 10 August 2005 (UTC)
Apologies if my lack of clarity here caused you to waste time. I can claim only ignorance and foolishness; I'm trying to catch up with the options and arguments on formatting, but I haven't located consensus yet on anything beyond no current solution is ideal, and wouldn't it be nice if MathML were here already, and it's a mess.
In summary, I don't know what is best for that page, and don't trust that what's best for me (my browser, my OS, my installed fonts) would be best for the majority, so I can only hope for and defer to someone better able to judge. Hv 18:10, 10 August 2005 (UTC)

Move of Inclusion (mathematics) to Inclusion map

I am proposing moving Inclusion (mathematics) to Inclusion map. For my reasons and how I plan to go about it see Talk:Inclusion (mathematics). If you have any thoughts on this move please comment on that talk page. Thanks. Paul August 18:42, August 10, 2005 (UTC)

I found this on VfD

Mathematics and space

Over at the Talk:Space#On arranging stuff in this article page there's a discussion about whether the section on Mathematics and space could be rewritten to contain a brief summary of how space works in maths, as at the moment it is pretty much a list of links. Could someone take a look at Space, which it is hoped will be a big picture article taking in the various uses of the concept of space, and see if work can be done on the Mathematics and space section. Thanks for any help or thoughts. Hiding talk 07:58, 11 August 2005 (UTC)

VfD for Mathematics and God

The article Mathematics and God is up for deletion. I voted to keep, here's the VfD page: Wikipedia:Votes for deletion/Mathematics and God. — Paul August 19:36, August 11, 2005 (UTC)

Of course, anybody watching Wikipedia:WikiProject Mathematics/Current activity would have discovered this a few days ago (sorry for the shameless plug, but Paul gave me a perfect opportunity). I moved the section "Articles on VfD" up to make it more prominent. By the way, it quite worries me that the article got a dozen delete votes and none of them bothered to comment on the reasoning brought up subsequently — I understand Ed Poor's frustration better now. -- Jitse Niesen (talk) 11:37, 12 August 2005 (UTC)
Yes that's how I discovered it by checking up on Wikipedia:WikiProject Mathematics/Current activity (I had forgotten to put it in my watchlist) And I agree about the comment on VfD. Paul August 16:50, August 12, 2005 (UTC)
BTW, its not showing up on Wikipedia:WikiProject Mathematics/Current activity any more ... maybe the time limits should be increased to more than a week? When I'm not in wiki-holic mode, more than a week can pass before I look at stuff. linas 23:58, 16 August 2005 (UTC)
The idea is that VfD discussions are supposed to last only seven days, so I thought it wouldn't be useful to list it longer. However, as you noticed, some discussions are not closed after that period, so now VfD pages are kept for ten days. I'm still trying to find the right balance on how long to keep the material. Of course, you can always look in the history of the page. -- Jitse Niesen (talk) 17:33, 17 August 2005 (UTC)
The VfD is closed. Keep won, though I'd hardly call it a concensus. The NPOV tag remains in the article itself (correctly, in my view). China, India, and the Arabic world have produced more notable mathematicians than just Ramanujan; those who voted to keep might help by finding quotations from other non-Western voices. Mathematicians like Russell and Clifford are well-known for their writings on God; I have added their remarks, and would invite others to add more of the kind. Especially nice would be more fun contributions like Erdős and (my addition) Hardy. --KSmrq 20:01, 2005 August 19 (UTC)

Category:Mathematician Wikipedians

I created Category:Mathematician Wikipedians as a subcategory in Category:Wikipedians by profession and categorized myself in there. Company is welcome. :) Oleg Alexandrov 23:28, 11 August 2005 (UTC)

What about Category:Wikipedian mathematicians? --R.Koot 23:56, 11 August 2005 (UTC)

Will people list themselves there or can anyone list them there? If the former, the list may be so incomplete as to be useless. Michael Hardy 21:28, 18 August 2005 (UTC)

If anybody is willing to go through mathematicians user's pages and add them to one or the other category, I will not mind. :) Oleg Alexandrov 01:28, 19 August 2005 (UTC)
Do you think that the others would? I think a directory is a great idea but perhaps the listing should be voluntary. Or maybe you could just leave someone a note on their talk page when you have added them (to give them the option to be unlisted). What do you think? --Kooky | Talk 19:13, 19 August 2005 (UTC)
To rephrase myself, if anybody is willing to go through mathematicians talk pages and mention to them about one or the other category, I will not mind. :) Oleg Alexandrov 19:56, 19 August 2005 (UTC)

There must be only one. If we do not merge these now, someone will do it later and more clumsily, and with much more work. There seems to be no standard, and Category:Wikipedian mathematicians is more idiomatic to my ear, so I propose we use that one. Septentrionalis 14:01, 19 August 2005 (UTC)

Category:Wikipedian mathematicians also fits better with Category:Wikipedians by profession. My vote is with Septentrionalis. I've added Wikipedian mathematicians to Category:Wikipedians by profession, so at least it is now obvious there are two conflicting page titles. --stochata 20:05, 19 August 2005 (UTC)
Don't know about you folks, but my profession seems to change every few years. (Three years ago, I was a "businessman". Now I'm an "engineer".) Classification by areas of interest, past and/or present, might be more accurate than whatever (non-)career is one is fated to, given the caprecious winds of the economy and slipperiness of the rungs of the social climbing ladder. linas 21:31, 19 August 2005 (UTC)

According to this, WP is not a directory. However, many categories for Wikipedians already exist. Since all the listings appear to be voluntary ones, I have no further comment on the subject. Oleg: Sorry about the misinterpretation. =) --Kooky | Talk 22:32, 19 August 2005 (UTC)

OK, I moved myself to Category:Wikipedian mathematicians. If more people feel to prefer this one, we will need to nominate Category:Mathematician Wikipedians for deletion and move the other people in there to Category:Wikipedian mathematicians. Oleg Alexandrov 05:48, 20 August 2005 (UTC)

I've now nominated Category:Mathematician Wikipedians for deletion. Note that the yokels don't seem too happy about the other page either (as per Koooky's comment above). --stochata 15:34, 26 August 2005 (UTC)

stochata, thanks. It seems there is a likelyhood both categories will be deleted, so you could go vote on that. Oleg Alexandrov 16:08, 27 August 2005 (UTC)

Announcing Jise's RfA

I would like to announce that I have nominated Jitse for adminship, and I am here shamelessly encouraging everyone to vote (in support I hope ;-). To vote or comment go here: Wikipedia:Requests for adminship/Jitse Niesen. — Paul August 16:58, August 12, 2005 (UTC)

Paul's nomination was successful, so I have now access to the admin tools. Thanks to everybody for voting. -- Jitse Niesen (talk) 12:28, 20 August 2005 (UTC)
Jitse, shouldn't you update your blurb in the participants list to reflect your newly elevated status? ---CH (talk) 00:04, 24 August 2005 (UTC)

PNG rendering improvements

Maynard Handley has put up a wiki demonstrating some improvements he has made to the LaTeX => PNG rendering process.

With his permission I offer you the URL: It will disappear within about a week so check it out soon.

In my opinion, some of the improvements are great (Wikipedia should definitely use them), some are so-so, and some are, let's say, ambitious.

I'd like to hear some opinions. Dmharvey Talk 21:39, 12 August 2005 (UTC)

The rendering looks worse to me. Dysprosia 03:21, 13 August 2005 (UTC)
Those are all terrible on my system (Firefox on KDE/linux with 1024x768 res) -Lethe | Talk 03:35, August 13, 2005 (UTC)
Correct link to the zip-file:
There is a particular, uncomfortably large, font size at which the rendering is readable (although still worse), otherwise the rendering is unreadable (Firefox 1.0.4 and IE 6 SP2 on Win XP HE SP2, LCD screen 1680x1050). I think the way it scales with font size is cool though. --nosfractal 04:21, 13 August 2005 (UTC)
The auto-scaling feature is indeed interesting, but the actual rendering, as noted above, does resemble an atrophied 16th century manuscript. (I'm using Konqueror.) linas 22:42, 16 August 2005 (UTC)
Having a stronger TeX->HTML conversion would make autoscaling irrelevant, however. A good first step has been taken in ensuring that the HTML text is the same font as the rest of the document, but the conversion is still so weak as to render less than signs in PNG and not use HTML (iirc). Dysprosia 22:52, 16 August 2005 (UTC)
Actually, in my browser (Safari 2.0, also with Firefox 1.0.4 for mac), is rendered (via HTML) in a different font to xyz. Am I doing something wrong? Dmharvey Talk 23:18, 16 August 2005 (UTC)
Dave, go to User:Dmharvey/monobook.css and add
span.texhtml { font-family: sans-serif; }
See User:Jitse Niesen/monobook.css for an example. Unless anybody disagrees that this is a good idea, I will try to get this in the site-wide stylesheet. -- Jitse Niesen (talk) 10:24, 17 August 2005 (UTC)
Looks like your skin. It looks quite nice and consistent in Cologne Blue, where math is in the same font as italics. Dysprosia 11:45, 17 August 2005 (UTC)
Not for me, if I switch to Cologne Blue, then (<math>xyz</math>) is rendered in a different font than xyz (''xyz''). Perhaps a browser thing, or something to do with the browser settings? More research needed. -- Jitse Niesen (talk) 11:59, 17 August 2005 (UTC)
That's quite bizarre. The fonts should be the same, anyway. Dysprosia 12:15, 17 August 2005 (UTC)
Hmmm. I've applied Jitse's suggestions (about User:Dmharvey/monobook.css). Now I get matching fonts in Firefox, but not in Safari. I've tried clearing caches and restarting the browser, and as far as I can tell Safari isn't trying to apply its own style sheets, so I have no idea what's going on. Ah well, no big deal. Incidentally, I don't often use Firefox, but now I'm looking at it, the italics in normal text look awful. The spacing after a word in italics is much too small. Dmharvey Talk 12:32, 17 August 2005 (UTC)

Number articles up for deletion

The aforementioned article is up for deletion. Uncle G 15:42:27, 2005-08-16 (UTC)

I've voted to delete this article. I agree with the sentiments expressed here: User:Uncle G/Wikipedia is not infinite. Paul August 16:59, August 16, 2005 (UTC)

New section: "Mathematics featured articles", comments?

I've added a new section: "Mathematics featured articles" to the project page. I might expand it a bit with some information on "Featured articles" and the FAC process. It might also be nice to track down and add the date when each article became an FA. Comments? Paul August 18:48, August 16, 2005 (UTC)

Ok I've made some changes to the "featured articles" section. In particular I:

  1. added a list of "former features articles"
  2. added the date when each article was "featured" and "de-featured"
  3. linked the date to the "featured" or "de-featured" discussion (for those I could find, older articles don't have nicely organized and archived discussions)
  4. used a tabular format rather than a list format.
  5. changed the section title to reflect the addition of "former" articles.

Paul August 20:28, August 18, 2005 (UTC)

Mathematical notation in articles

I'm new here, and I'd like clarification about use of mathematical notation, specifically in set theory and mathematical logic. For example, my new stub of Transitive set uses the ∈ (&isin;) symbol, which the guidelines suggest should be replaced by the text "is in". Arthur Rubin 00:29, 17 August 2005 (UTC)

Generally speaking, you would want to follow the guidelines. However, my opinion in your case is that using ∈ is fine, essentially because the audience for that article would be expected to be familiar with standard set-theoretic notations already. Dmharvey Talk 03:23, 17 August 2005 (UTC)
Two distinct concerns apply, both of which argue for "is in". The first is whether a reader can properly view the character in their browser. This would not be a problem for a PNG image, but that's ugly inline. The second concern is audience comprehension. For this brief article there is little to be gained by technical notation; "is in" may invite more readers.
The implications of these two concerns vary among articles. We can only hope that the character set problem will go away soon, but meanwhile the list of "Insert" characters below the edit window is considered safe. In the case of a long, technical article like Kripke semantics, proper notation is essential, so use it — though as little as possible in the lead paragraphs, and in <math></nomath> brackets elsewhere. --KSmrq 04:46, 2005 August 17 (UTC)
Good points by Dmharvey and KSmrq. Oleg Alexandrov 15:16, 17 August 2005 (UTC)

more about improving inline PNGs

I've been trying to improve on what Maynard Handley did with the PNGs.

There are still severe problems (mostly relating to Windows), and it's not good enough for deployment, but I think it's starting to get somewhere, and I'd appreciate some opinions.

Check out User:Dmharvey/Inline_PNG_discussion.

Dmharvey Talk 17:15, 17 August 2005 (UTC)

Requested move

Could an admin move Menelaus theorem to Menelaus' theorem? Note that the page's principal author User:Tokek has left a note on talk:Menelaus theorem regarding the choice of title, but as I read it it doesn't seem that Tokek would find this change objectionable. —Blotwell 06:57, 20 August 2005 (UTC)

I did it. Now Menelaus theorem is a redirect to Menelaus' theorem. Hope that was a correct move. --Zero 08:28, 20 August 2005 (UTC)

Framed box around formulas

Yesterday I removed with my bot framed boxes around formulas wherever I could find them. I mean, boxes of the form:

This is a theorem, or a formula.

I based my reasoning on the discussions at Wikipedia_talk:WikiProject_Mathematics/Archive10#Dotted_framebox_around_formulas and Wikipedia_talk:WikiProject_Mathematics/Archive6#A_little_note_on_using_purple_dotted_boxes but Paul rightly pointed out that a preliminary discusion would have been good. So, belately, I wonder, what do people think of these boxes? Thanks. Oleg Alexandrov 18:46, 20 August 2005 (UTC)

I don't feel strongly one way or the other, but I never use the boxes. I think they should probably be left out unless something really needs to be emphasized. Bubba73 19:28, August 20, 2005 (UTC)
I don't much like them. I think it would be good to remove them, at least in the cases I've seen. Perhaps there might be a use for some more visually pleasing way (not purple dotted lines) to set off certain text. But it would be best to use such devices sparingly, if at all. Paul August 19:36, August 20, 2005 (UTC)
I think the borders are gaudy and obtrusive, but I'm not going to bend anyone's arm either way. --Kooky | Talk 20:28, 20 August 2005 (UTC)
Can we have hot pink with circulating neons? --Zero 02:44, 21 August 2005 (UTC)

Characterizing Notability of Mathematicians

Hi all, I am a non-member dropping by to alert you all to an ongoing VfD discussion.

The issue is: which mathematicians should have biographies in the Wikipedia? I think a simple and common sense rule of thumb (the title is a joke; of course I don't expect a mathematically precise criterion) should be:

a wikibiography of mathematician M, which claims no non-mathematical notability for M, should explain or at least describe at least one clearly notable mathematical achievement of M.

I am no doubt hardly the first to point out that with thousands of person obtaining a Ph.D. in math every year, and gadzillions of math professors around the world, and tens of thousands of members of SIAM, AMS, MAA, and other mathematical societies around the world, simply earning a Ph.D. or publishing some research papers probably shouldn't qualify one for a biography.

Here is a more bizarre possibility: suppose the article claims that M is notable because he won the Y Prize, it should link to the formal English language Y prize citation for M. If that doesn't exist (in English), at the Y Foundation website, and if there is no other grounds for M's alleged notability, I question whether M should have an entry in the English language Wikipedia.

No, I didn't make that up. This is exactly the argument some nonmathematician made in a VfD. (Quick now: has anyone here ever heard of the Zois Prize? Before reading the preceding sentence?)

Yesterday, I happened across several biographies listed in Category:Algebraic graph theory which I think violate my simple rule:

  1. Aleksander Malnic
  2. Dragan Marusic
  3. Tomaz Pisanski

I have nominated them for deletion as non-notable. I think the first two are clear cases, the third maybe a bit less clear. Just to be clear, in each case, I would be equally happy with either of the following outcomes:

  1. the article is deleted on the stated grounds,
  2. someone comes up with a useful description of a truly notable mathematical achievement of the subject.

I hope many of you will drop by those pages and vote one way or the other, but I'd also like to see any comments on the bigger issue raised in the subject line: how can one characterize which mathematicians are notable?

In retrospect, I probably should have considered trying to contact authors/editors of these articles before making my VfD nominations. Has anyone had some good experiences along these lines to share? Or advice on how to proceed if a similar situation arises in the future?

Someone raised another issue: these three men all happen to appear on a List of Slovenian mathematicians, so there might be some, er, patriotic rationale for creating these biographies. I don't want to get involved in Balkan politics, so I'd just say that I did recognize one name on that list, Josef Stefan, and I would certainly agree that Stefan is notable and should have a biography here. I'd like to see the others include an explanation of some clearly notable mathematical accomplishment, or else I think they should probably go.---CH (talk) 21:50, 22 August 2005 (UTC)

Oh dear: to forestall misunderstanding, of course I did not mean to imply that whether or not I recognize a name is an adequate criterion for mathematical notability. But if none of the members of this project know anything about mathematician M, and the biography doesn't help, I would say that biography should probably go.

Another thing: I overlooked another name I recognize: Josip Plemelj. Ironic I missed that, because I am gearing up to write about something he was involved with.---CH (talk) 22:04, 22 August 2005 (UTC)

P.S. Someone commented in the VfD to the effect that the fact that some towering figure doesn't yet have a biography, while some lesser figures already have ones, is not by itself grounds for deleting anything. I agree; clearly, Wikipedia's growth is haphazard so this will be a not infrequent occurrence. The balance issue raised in these three cases goes far beyond that, I think, but all I am really trying to say is that, IMO, the average reader of a biography on Wikipedia should not be left with serious doubt that the subject is indeed notable, as I was after reading these three biographies. Again, I'd be happy if someone who knows more than I do about them can convince me I am wrong by telling us all (by expanding the biographies) about some clearly notable accomplishment. But some prize I have never heard of? Doesn't help me. Some very rough analogies (not very serious):

  • earned a Ph.D.: made the local Little League baseball team
  • serves on the math faculty at some uni: plays minor league professional baseball
  • won tenure or an obscure award: got a pat on the back from the team after a big game
  • made a major contribution to mathematics: set a significant major league baseball record
  • won an internationally known mathematics award: won the MVP award
  • won the Field's Medal: entered the Hall of Fame

(I should confess that I don't know much at all about baseball, I'm just trying to, er, play along with a favoriate analogy among Wikipedians.)---CH (talk) 23:58, 22 August 2005 (UTC)

JYolkowski has suggested several times (if I understand him correctly) that the mere verifiability of stated facts in an biography is sufficient grounds for keeping it (see my talk page). This doesn't make sense to me: name person X, birthdate, and birthplace, and someone can probably verify that information. Does that alone qualify X for inclusion? I think it should be rather the notable substance of stated facts (or lack thereof) which qualifies X (or not) for having a biography here.

I seem to be trying to summarize, er, notable comments recieved elsewhere. I have to take the blame for this. Due to the accidental way I got into this (and my inexperience in Wiki discussions of this kind), various useful (or bizarre) comments are now scattered over the talk pages of the three articles, my user talk page, and the vfd pages. Sorry for the confusion!---CH (talk) 00:35, 23 August 2005 (UTC)

Jitse actually found the citation (in Slovenian, I guess) of some obscure award to Marusic :-) So I did the obvious thing and awarded the very first Biographical Barnstar for Brain-numbingly Obscure Web Research to Jitse Niesen. Congrajulations, Jitse! This is such an obscure award that until a few minutes ago it didn't even come with a bronze plated pewter star. But you can verify that Jitse won it!-- just look here! Anyway, if some kind person can translate this well enough, maybe I will change my own vote. Even better, said kind person can add a description (in English) of Marusic's notable achievement in the original article.---CH (talk) 01:02, 23 August 2005 (UTC)

Hi CH, by posting here, you are now officially a member. You might be interested in considering the positions of the Association of Inclusionist Wikipedians as well as the Association of Deletionist Wikipedians. There are some serious philosophical battles on these issues. Amazingly, WP is filled with oodles of non-encyclopedic, non-notable material, e.g articles on ancient soviet submarines, underwater electrical cables, television shows, Pokemon characters, and rock-n-roll bands. linas 04:57, 23 August 2005 (UTC)
Hi CH, to add to what Linas said above, the issue of notability on Wikipedia is unsettled, see: Wikipedia:Notability, Wikipedia:Importance, and Wikipedia talk:Fame and importance. Since Wikipedia is not paper, I lean toward the inclusionist idea that "verifiability" is the more important concept, since it is a necessary condition to be encyclopedic, and being that it also implies a certain minimal amount of notability, is arguably sufficient. (For what it is worth, I believe this is the view held by Jimbo Wales). Paul August 16:11, August 23, 2005 (UTC)

OK, some anon has translated the now notorious Zois prize citation of Marusic, which led me to guess that if he is internationally recognized, some papers by him would appear in a review paper I happened to have at hand. This turned out to be the case, so I changed my own vote in the VfD to a lukewarm keep.

I'd like to try to summarize a few more valuable points which came up:

  • if someone knows of a mathematician who rarely if ever publishes in English but has done extraordinary work (every mathematician can think of examples), of course we all agree that this person should have a biography in the English language Wikipedia, because such a person has clearly made a notable contribution to the body of human knowledge.
  • exhaustive lists of Lusitanian mathematicians might be appropriate in the Lusitanian language Wikipedia, but should be discouraged in the English language Wikipedia, which clearly has a special responsibilty to students all over the world because English currently plays the role of the scholarly lingua franca.
  • the problem with exhaustive lists is that they impede navigation by the generic reader, who wants to find and absorb information on a specific topic; particuarly in a deeply and confusingly interconnected subject like mathematics, eliminating cruft is essential if these pages are to become (remain?) a valuable resource for students and the general public all over the world, which I take it is our goal in the EN language Wikipedia.
  • the sports metaphor breaks down here, because reading about mathematics is far more challenging and daunting than reading the sports pages, and we have a special responsibility to help people find useful and intriguing information about mathematics, which inevitably means taking them places they didn't expect in other parts of the math pages. We must avoid disorienting them or landing them in a huge and amorphous category. So if exhaustive lists "for the sake of keeping exhausting lists" must be kept out, or at least in special categories.
  • how ironic (if unsurprising) that the mindless drones are not the mathematicians--- who were alleged in the popular culture of the first part of the last century to spend their time poring over long lists of meaningless numbers--- but the sports fans! The mere fact that no non-mathematicians expressed surprise at our concern for organization, sanity, good judgement and balance, might suggest that the general public now knows better, or has a new set of misconceptions about us, but probably it only means that the non-mathematicans who dropped by weren't in a contemplative mood.
  • a prize citation by itself means little; mention in a review paper by an international authority is a much more reliable indication that person X, working in some field in which one is not oneself expert, is a major player.

Paul August: up above I think I expressed my take on inclusion; fine by me as long as it doesn't intrude upon the learning experience of the generic user. My concern is to keep that from happening. A mixture of discouraging cruft (hopefully by the art of gentle persuasion) and segregating it is probably the best answer.

Two points, first, "providing a learning experience" for our readers is a noble goal, but strictly speaking, that is not the mission of an encyclopedia, and second, If we are sufficiently creative, having subjects with low notability, should not "intrude" upon such a goal anyway. Paul August 23:02, August 23, 2005 (UTC)

Linas: OK, I'm adding back my name, but I need to focus on the GR WikiProject at least for the rest of this year, because I promised to get some serious work done on that. Yes, I'm talking to you, and all is forgiven, but Linas, I really hope that in the future, you in particular will pay attention to clues that you might be getting on my nerves (or keep an eye on the wikistress meter on my user page), OK? If that happens, I'm sure I'll try to tell you, so if you just remember to be a good listener when interacting with me all should be fine.---CH (talk) 22:27, 23 August 2005 (UTC)

Can more people help me out?

I have a question/problem/something-I-don't-understand that has been bugging me for years. I have posted it at the bottom of Talk:Infinity. Thank you already to Paul August. --Lord Voldemort (Dark Mark) 17:20, 23 August 2005 (UTC)

weird vandalism

There have been some rather strange edits to Galois theory in the last few weeks, all emanating from IP address, just deletions of large random chunks of text. What is especially odd is that this IP address appears to be making genuine edits to other articles. Any ideas? Dmharvey Talk 18:49, 25 August 2005 (UTC)

This is the IP address of a cache server fom United Online, so is most likely used by a lot of different users. --R.Koot 18:58, 25 August 2005 (UTC)

"Tav (number)" article

Take a look at Tav (number). Is this valid? Salvageable? The original article is credited to an IP (which has no other math-related edits), and subsequent edits by others have left the basic text unchanged. Obviously, this article needs either a rewrite or deletion. — Nowhither 13:50, 26 August 2005 (UTC)

It has a valid basis but is so poorly written as to be incomprehensible. See the footnote on page 3 of this Postscript document. Here is Tav: ת --Zero 14:11, 26 August 2005 (UTC)


The notations used by the cluster of articles close to sigma-algebra are inconsistent with one-another; I'd like to fix this, but only after some agreement on a unified notation. Please see Talk:Sigma-algebra for details. linas 13:58, 26 August 2005 (UTC)


Almost a million (well, nearly) pages still point to sheaf rather than to the moved sheaf (mathematics). There were good reasons not to move it. Charles Matthews 20:33, 26 August 2005 (UTC)

There's an entry for it on the disambiguation page. What's wrong with that? --Kooky | Talk 20:53, 26 August 2005 (UTC)
Well first, the article at "sheaf" should be about the mathematical kind if that is the "primary" meaning of the word (see: Primary topic disambiguation). Of course that the mathematical meaning is the "primary" one is debatable, but the great number of links to it vs. the others is suggestive that it is (at least for the here and now). But if it is decided that it should stay at "sheaf (mathematics)", then the links to "sheaf" which want "sheaf (mathematics)" need to be changed. Paul August 21:17, August 26, 2005 (UTC)
Actually, there are 109 articles listed on the "what links here", of which TWO are not mathematics-related. I vote to change it back. Dmharvey Talk 21:25, 26 August 2005 (UTC)
to Paul August: I see. That makes sense. I'd be willing to work through all the mathematical articles that point to sheaf and redirect them to sheaf (mathematics). If it were decided later on that the mathematical definition were no longer the "primary" definition, wouldn't it have to be done anyhow? --Kooky | Talk 22:18, 26 August 2005 (UTC)
If you can make a good case that the primary definition of "sheaf" is moving away from the mathematical one, then I might be persuaded to change my mind. However, the overwhelming proportion of wikipedia articles are presently pointing to the mathematical meaning of Sheaf, and this seems to be evidence pointing the other way. Dmharvey Talk 22:42, 26 August 2005 (UTC)
Gauge, who moved it, contributes to mathematics articles, and I see no discussion anywhere calling for a move. So I can't imagine there will be an outcry if we just quietly move it back, or whatever administrators do. --KSmrqT 22:58, 2005 August 26 (UTC)
The meaning to which the most links point should perhaps not always be considered primary. For example, the word sheaf was probably chosen for use in mathematics to be suggestive, precisely because the word has another, non-mathematical meaning. The effectiveness of the mathematical usage to some extent depends on that other meaning. Michael Hardy 22:51, 26 August 2005 (UTC)
Almost no one outside of math actually uses the word sheaf; what, pastoral literature? Move it back. linas 00:37, 27 August 2005 (UTC)
Change it or leave it, it's all the same to me. --Kooky | Talk 01:12, 27 August 2005 (UTC)

Agree to move it back to sheaf. Oleg Alexandrov 16:03, 27 August 2005 (UTC)

Sorry, I don't know how I missed the remaining links. I will contribute to fixing them or moving them back, based on what we all decide here. Regarding the move, I was thinking that "sheaf" is a common enough word that it could have many possible current (and future!) meanings. Personally, I don't see any harm in having a more specific link to the mathematical definition (so long as the remaining links are fixed). However, if you'd like to go back to the old link, that's fine with me too. - Gauge 16:58, 28 August 2005 (UTC)
I have fixed the remaining old mathematical links to point to the new location. Apparently at least a couple of articles have already referred to sheaves in the agricultural sense. - Gauge 04:40, 2 September 2005 (UTC)

Aged requests

Some of you may remember that in August 2003 a user began adding a huge number of missing math topics to Requested articles. There were well over a thousand requests added, but through the labour of our math people all but seven of them have now been filled. These last few requests are now listed on Articles requested for more than two years. Since they have taken so long to be filled they are probably very obscure and difficult to write about, and certainly need some expert knowledge. It would be great if some math people could take a look at Articles requested for more than two years and try to clear these final relics. - SimonP 23:28, August 26, 2005 (UTC)

Math Babel

I've just made a comment on the category deletion pages for Category:Mathematician Wikipedians about a Math version of the Babel project. Then I realised it's actually only an extension of the Babel project. Below are some sample categories for discussion, and we could make up a pretty box template like the babblers:

  • Math native speaker of math. This person works as a math professor or similar role in industry.
  • Math-N near-native speaker of math. This person is either engaged in a math doctorate, or works where a very high level of math is required e.g. as a physicist, etc.
  • Math-3 very high level of math. Works where a high level of math is involved (e.g., actuary, computer science, etc), or is engaged in a higher level degree in math, physics or other math related subject.
  • Math-2 has taken or is taking an undergraduate degree, in math, physics or other math related subject.
  • Math-1 basic mathematical ability and literacy. Typically working in an environment where an understanding of math or logic is desirable, such as an accountant.

If we preferred it could be a proper equivalent of Babel, where statisticians, applied mathematicians and pure mathematicians have their own boxes, and people like me can be Pure Math-1! --stochata 11:12, 27 August 2005 (UTC)

Not sure I like this fine level classification. OK, if one wishes to do that, one could. But those Babel thing are ugly and take a lot of room on the page. Oleg Alexandrov 16:10, 27 August 2005 (UTC)
The only problem I have with that classification is that it doesn't distinguish different types of math-nativeness. For example, I might be classified as "native" myself, but when it comes to articles on algebraic topology, numerical analysis, several complex variables, or any number of other topics, my understanding is really probably somewhere between Math-3 and Math-N at most. In other words, a lot of the time, the level would depend on the particular subject itself. Revolver 21:52, 2 September 2005 (UTC)
I think those categories are setting the bar too high. After all, we don't make up separate categories for "native speaker of english", "native speaker, additionally is studying english literature at PhD level", and "native speaker, additionally teaches english literature and phonics at university level". I think what you have as "Math-3" is the highest level I would be willing to categorise on babel. After that there are just too many problems with specialised areas, as Revolver notes. Dmharvey Talk 22:10, 2 September 2005 (UTC)
I did wonder about the height of the bar, especially as compared with "native speaker of English" (which covers perhaps 300 million+ people), as opposed to perhaps a few thousand math professors in higher education. However, sometimes I feel it is worth knowing that X is actually a math professor, rather than a doctoral student. I also agree that specialised subdomains complicate thing. I would also be Math-3 (alternatively, Graph Theory-N, Number Theory-1, Statistics-2) under this classification, but then I do feel that others are better qualified than me, and would appreciate knowing who is who (and would also like other editors to know that my math isn't always 100%, and needs checking). --stochata 12:33, 4 September 2005 (UTC)
A math(s) professor may advertise themselves as such on their user page without a babel notice, if they so choose. Perhaps what you really want is a "Mathematical Wikipedians, classified by area of specialisation" page. The difficulty is that often people categorise themselves too high because they don't know any better. For example, there would be a fair few high school students who would describe themselves as accomplished in "geometry and algebra", despite not knowing the first thing about what real mathematicians in these areas actually do. Dmharvey Talk 12:54, 4 September 2005 (UTC)

Merge sigma additivity into measure (mathematics)?

The article sigma additivity used to be a redirect to measure (mathematics). As part of the PlanetMath Exchange project I copied over the article "additive" to sigma additivity, replacing the redirect. User:Blotwell is now suggesting that sigma additivity be merged into measure (mathematics). I feel like the topic is deserving of its own article, but this is not my area of expertise, (not that I have one ;-) and I would appreciate if other knowledgeable editors could help decide what the best thing to do is. Please comment here. Thanks — Paul August 19:21, August 27, 2005 (UTC)

New math categories

As part of working on categorizing articles copied from PlanetMath — the PlanetMath Exchange project, I noticed that there might be a need for more math categories from subjects listed in the Mathematics Subject Classification (2000 edition). Here's the categories I have in mind:

  1. Category:associative rings and algebras as subcategory in Category:Abstract algebra, as per MSC 16-xx, Associative rings and algebras
  2. Category:nonassociative rings and algebras as subcategory in Category:Abstract algebra, as per MSC 17-xx, Nonassociative rings and algebras
  3. Category:Difference equations and Category:functional equations as subcategories in Category:Equations, as per MSC 39-xx, Difference and functional equations
  4. Category:Global analysis and Category:analysis on manifolds, subcategories in ???, as per MSC 58-xx, Global analysis, analysis on manifolds
  5. Category:Sequences, subcategory in Category:Mathematics, as per MSC 40-xx, Sequences, series, summability
  6. Category:Mathematical biology as subcategory in both Category:Mathematics and in Category:Biology, as per MSC 92-xx, Biology and other natural sciences

I am aware that the Mathematics Subject Classification is not directly applicable to Wikipedia math articles, still, probably it can give some inspiration. I am most uneasy about the global analysis and analysis on manifolds thing. Any suggestions and discussion of the above are very welcome. Oleg Alexandrov 22:57, 27 August 2005 (UTC)

Category:Nonassociative algebra would be good. Nobody can remember categories A&B, so let's not have any more. Category:Global analysis was 'big in the 1960s' but I think should probably not be used here - cover by means of other ones (possibly one on infinite-dimensional manifolds, one day). Category:associative rings and algebras is really just ring theory, which we have. Charles Matthews 09:45, 28 August 2005 (UTC)
Charles, should it be Category:Nonassociative algebras, meaning plural? Oleg Alexandrov 15:36, 28 August 2005 (UTC)

(I changed the list to a numbered one, to make referring to it easier). I think (1) and (2) should be under ring theory, as I find it hard to see there being enough articles to justify addiational catergories. Similarly for (3) - I don't think there's enough articles to justify additional catergories. For (4), it seems the seqeunce catergory is broadly equivilant to the catergory you suggest putting it under. On the other hand, I definately agree with doing (5) as you suggested. It is important to remember that the MSC classification is designed to classify maths papers, not maths itself. Tompw 11:50, 28 August 2005 (UTC)

So: Category:associative rings and algebras can be just replaced with Category:Ring theory, and probably Category:Difference equations and Category:functional equations are premature, with Category:Equations being enough. However, I would argue though for creating Category:Sequences. It could contain as subcategories Category:integer sequences and Category:mathematical series. Any comments on this? Oleg Alexandrov 01:54, 30 August 2005 (UTC)

Fibonacci numbers subscript style

I raised this question on Talk:Fibonacci number a while back, but didn't get any comments, and since this also concerns other articles, I'll bring it up here. The Fibonacci number article uses the notation F(n), but my impression is that Fn is far more common in other works (both versions are used more or less randomly around Wikipedia). Which one should it be? Consistency would be desirable. Fredrik | talk 18:56, 28 August 2005 (UTC)

I think I prefer Fn, both PlanetMAth and MathWorld use that notation. And Fibonacci number uses both! I would vote to change it to Fn everywhere for consistency. Paul August 20:15, August 28, 2005 (UTC)
Agree with Fn as the preferred notation. Oleg Alexandrov 20:46, 28 August 2005 (UTC)
I agree too. I think subscripts are preferred when you have them available. some literature uses f instead of F. Bubba73 22:54, August 28, 2005 (UTC)

Both notations are common and should be defined. F(n) notation is better for complex expressions such as F(n-3) or worse I think. For simple expressions I prefer F_n though.--MarSch 16:01, 30 August 2005 (UTC)

Game theory wikiproject

Hello all - In the interest of standardizing and growing wikipedia's coverage of game theory, I have started a WikiProject on game theory. We could use some mathematicians help over there. (For instance, we could use an article on the Kakutani fixed point theorem which is used in the proof of the existence of Nash equilibria.) I hope that some folks will come join in! --best, kevin ···Kzollman | Talk··· 02:22, August 30, 2005 (UTC)

featured math articles template

I've templatized the math FAs, although thanks to Paul it doesn't add much :) Any ideas about this? --MarSch 15:41, 30 August 2005 (UTC)

I have objected on Wikipedia talk:Featured articles. --RobertGtalk 15:41, 30 August 2005 (UTC)
I doubt how much use a template is. Oleg Alexandrov 15:59, 30 August 2005 (UTC)
At the time I created the FA section on our project page, I thought about suggesting this at the FA talk page, and decided not to, since I thought it would be easy enough to maintain our list separately (at least for the foreseeable future). I also figured (correctly as it turns out) Raul wouldn't much like it ;-) Paul August 19:54, August 30, 2005 (UTC)

Math equations to plain english

There is an interesting thread at Wikipedia:Village pump (proposals)#Math equations to plain english. Oleg Alexandrov 19:02, 30 August 2005 (UTC)

Map between AMS math articles classfication and Wikipedia categories

Based on the feedback above, I created a table listing how Wikipedia categories are in correspondence with the AMS Mathematics Subject Classification. Again, this is needed for automatic categorization of articles imported from PlanetMath but would be a curious thing to look at in general. See link at User:Mathbot/Wikipedia categories and AMS MSC classification. Any feedback welcome. Oleg Alexandrov 23:22, 30 August 2005 (UTC)

Are you not aware of areas of mathematics? My only complaint is that it links to articles, when I think it should link to categories. The other complain is a lack of the next level of detail: at one point, I attempted to also add a list of categories corresponding to subcats of MSC 11, but was rebuffed. linas 04:12, 1 September 2005 (UTC)
I am aware of that list, and it was very helpful in compiling my list of categories. No, I would not think that page should link to categories — linking to the article is more informative, and from there the link to category is one click away. But maybe a wider discussion is needed on this. Oleg Alexandrov 04:56, 1 September 2005 (UTC)

Rewrite of Boolean algebra, or new article?

There is a discussion going at Talk:Boolean algebra about rewriting it, or perhaps writing a new article. Several people think the article is too technical and difficult to understand, and User:Plugwash (who says he doesn't understand the current article at all) has made an attempt at rewriting it & mdash; that has been reverted (by me!). Please join in the discussion ;-) Paul August 17:12, August 31, 2005 (UTC)

I've concluded that the article for mathematicians (the current one) needs to be separated from the article for non-mathematicians, which I wrote and placed under Boolean logic. It may need to be moved again, though, as I am getting considerable complaints from PhDs over it's placement there. StuRat 19:45, 18 September 2005 (UTC)

the state of "product/sum" articles

It is my personal belief that all of the "product" articles collectively are in a confusing and sorry shape. Some things are misnamed, some articles have no apparent reason for their content organisation, other things aren't clarified enough, etc. At the heart of the matter seems to be a failure to organise, name, and clarify topics by keeping in mind their category theory meaning. This doesn't mean you have to know category theory to understand anything, but category theory does point a clear direction of how things should be organised, and it's not the direction we're going.

There are 4 major ideas going on in all these articles, based on 2 criteria with 2 options each: first, product or coproduct/sum; second, external or internal. That makes

  1. (External) product
  2. Internal product
  3. (External) coproduct/sum
  4. Internal coproduct/sum

A lot of things are named "sum" that are really products, and a few things that are "internal" aren't clearly identified that way (so could be confused with the "default" external case). For example, direct sum of groups is not about the (external) direct sum, or free product, it's actually about the internal weak direct products of groups. Also, in many cases, you can form the product/sum like you do the sum/product, as objects, but it's not a universal object. Similarly, you can take the "abelian" sum of arbitrary groups, but it's not universal. This is sometimes called the "weak direct product" or "restricted direct product". This distinction between what is an object and what actually is universal is missing in many places. You don't have to mention it directly, but it seems it should guide the presentation. Revolver 21:01, 31 August 2005 (UTC)

The universal and unconditional applicability of category theory is a PoV. I believe the definition complained of is Jacobson's, but I will check. Septentrionalis 01:33, 1 September 2005 (UTC)
After looking around some places, the point is taken. There seems to be a conflict in terminology between researchers in pure group theory and others. Even people writing general algebra books (Jacobson is a bit old to guide current usage, it seems to me), the tendency seems to shy away from "direct sum". But a number of people seem to use it, and for those that use it often, I can imagine how the longer name would get old after a while.
Just to put my comment in context, my first immediate reactions upon reading the term "direct sum of groups" were (honestly)
  1. I've never heard of that before.
  2. There shouldn't be such a thing.
But apparently, the term is used fairly commonly among group theorists. I had no idea about this. For the reasons I said above, I think it may seem counterintuitive or contradictory to many people. Perhaps a strong statement expressing that although the term "direct sum" is commonly used when discussing decomposable groups and so on, it should not be confused with the "direct sum" concept of abelian groups, modules, Banach spaces, abelian varities, representations, etc. which most people are more familiar with. Revolver 05:00, 1 September 2005 (UTC)
Besides direct sum of groups (which does indeed sound crazy at first blush), can you wikilink the other articles you are talking about? Its quite an undertaking to make all the various articles more category-like and at the same time point out the various colloquial flavours in each. A uniformity of style would be better achieved by one person combing over all of these articles, which is no small task. linas 05:12, 1 September 2005 (UTC)
One of the used to be direct sum, which was mostly about direct sums of modules, but also had other stuff. The case of groups was cited as a special case of modules, which isn't true, so I changed it to abelian groups, renamed the article direct sum of modules, and added some other remarks. Direct product seems redundant to me, and could probably be used as a disambiguation page, moving most of the material to separate articles for the cases of groups, vector spaces, and topologies. The only thing distinguishing why these are collected together here vs. others which are not is that they are called "direct product", that's why I think a disambig is good. Beyond this, just a clear distinction between internal/external products in some of the cases, comments on alternative terminology (e.g. I had always heard "weak/restricted direct product", etc.), and checking to see that statements made for the finite case really hold for the infinite case (I already corrected one of these at direct sum of groups.) Revolver 16:46, 1 September 2005 (UTC)
I'm not so much interested in "making them more category-like" then I am about making alternative terminology clear and making the non-category vs. category discussions more clear-cut. For example, in the case of a finite collection of abelian groups, the direct sum and direct product are the same as objects, so in the first discussions of what these terms mean (as objects), there's no need to qualify the statement. But, when moving to the category discussion, it should be pointed out that these are not the same thing, even though the objects are the same. The distinction between objects/limits doesn't belong in the primary discussion, but it should belong somewhere. Revolver 16:53, 1 September 2005 (UTC)
Revolver, I think all of what you are saying is eminently sensible. A lot of work though! :-) Dmharvey Talk 17:29, 1 September 2005 (UTC)
Yes, and being the one who mentioned it, I feel I should try to do something. That's the thing about complaining — it carries responsibility! Revolver 21:52, 2 September 2005 (UTC)

Sep 2005 – Oct 2005

Games and determinacy

There's some fairly good work on WP about determinacy, but it's a bit haphazard. The axiom of determinacy article doesn't explain very clearly what a game or a strategy, or in particular a winning strategy, is. Winning strategy itself tries to be all things to all people. See my remarks in Talk:Axiom of determinacy and Talk:Winning strategy#Organizational questions for some thoughts with no clear conclusions, but I think a good starting place for trying to get the (nonexistent) category into better shape.

A couple of things of which I recently became aware have given me a little more sense of urgency about this. There's a Wikipedia:WikiProject Game theory, and they added winning strategy to it, which may be appropriate if that article should be ceded to the game theorists, and another written for the determinacy theorists (I'm thinking of writing a Game (set theory) article to subsume a whole bunch of these things, and change links from other articles to it). See my remarks in User talk:Kzollman#Game theory wikiproject.

Also there's apparently a category, Category:Combinatorial game theory, which deals with John Horton Conway type games.

I think this needs to be sorted out before it becomes an irretrievable mess. Would anyone be willing to work on a Wikipedia:WikiProject Determinacy?

On further reflection, I think the central article of the Determinacy category should just be called Determinacy. It's a much more general topic than Axiom of determinacy, which currently serves the purpose of a central reference point. You can see an outline at User:Trovatore/Sandbox/Determinacy. --Trovatore 01:45, 2 September 2005 (UTC)

So the article is far from finished, but there's enough there to put it in article space I think, and I've done so. --Trovatore 04:33, 2 September 2005 (UTC)

Axioms of an equation

I like the intent of this new stub, but I think this material really belongs in Elementary algebra. In a sense, the material is already there, but Elementary algebra seems to already assume that the reader is familiar with the semantics of "=". In other words, Elementary algebra is not quite as elementary as it could be. The new article Axioms of an equation appears to be attempting to fill the gap for, say, late primary or early secondary school students, by explaining more explicitly how to work with "=". Dmharvey File:User dmharvey sig.png Talk 02:57, 3 September 2005 (UTC)

We have equals sign and equality (mathematics), and various other pages on equations, no doubt. The Axioms page should really be re-styled as an easy introduction to those topics. Charles Matthews 09:00, 3 September 2005 (UTC)
Any quantity can be added to both sides. Some equations came from physics, and you can not add joules to meters. For algebraic equations, I would rephrase it to something like "validity of equation holds if you add same thing to both sides". Besides what's about adding two equations?(Igny)
Well, getting picky about that, any dimensionless quantity can be added to both sides of an equation in dimensionless form. But in algebra everything is dimensionless anyway. Adding two equations, ie add A = B and C = D to get A + C = B + D, should follow in two steps A + C = B + C and 'substituting equals for equals'. Charles Matthews 19:43, 3 September 2005 (UTC)
You can also raise both sides to a power, apply the logarithm on both sides, take the square root on both sides (be careful with the signs though)... this article isn't very complete, or could just be summed up in one line. --R.Koot 19:47, 3 September 2005 (UTC)
Hehe, which I've just done, but this stuff should really be merged somewhere. --MarSch 10:27, 5 September 2005 (UTC)

This discussion is already archived, but I want to report that I've merged the article into Equation. Melchoir 00:18, 27 November 2005 (UTC)

Length of a stub

Exactly how long should an article be before it stops being considered a stub? I removed [Digamma function]] and earlier (before Linas's major edit) Harmonic number from Category:Mathematics stubs, but I am not currently sure if articles such as Omega constant are still to be considered stubs or not. Scythe33 01:57, 4 September 2005 (UTC)

The criteria for "math-stubbiness" have baffled me for some time. I don't think it should purely be a question of length - I think the question of whether anything more can be said about the subject should be a criterion as well. But this inevitably becomes subjective. For example, I don't think quartic should be classified as a stub, even though it is very short. It defines the word in question and gives links to quartic equation and quartic function - I struggle to see what else could be added to make it non-stubby. But that is just my opinion. Does anyone have any objective criteria for determining stubbiness ? Gandalf61 10:25, September 4, 2005 (UTC)
Opinions differ (as always). I think that stubs are articles for which it is immediately obvious that they are missing something. An article with just a definition is a stub, an article with more than a definition probably not, an article with definition and some discussion on why this concept is important is never a stub. Some examples: Digamma function and Harmonic number were not stubs when Scythe33 removed the message and Omega constant is not a stub either; on the other hand Peetre's inequality, Egon Pearson and Cauchy surface are stubs. I consider Artin reciprocity and cylindrification as boundary cases; if forced to decide, I'd classify only the second as a stub. Of course, there are exceptions: quartic is not a stub because I consider it as a disambiguation page. You can use {{expansion}} for articles which are not stubs but still need expansion; you'd probably also need to specify what needs to be added. This is all just my opinion of course; I just had a discussion with an editor of a very different opinion. See also Wikipedia:Stub#Identifying a stub. And of course, don't start a fight about whether an article is a stub. -- Jitse Niesen (talk) 12:05, 4 September 2005 (UTC)

Category:Mathematics in India

I just discovered this new category as a subcategory in Category:Mathematics. While I have nothing against Indian mathematics, I wonder if it is wise to have such a category. Next thing we know is Category:Mathematics in United States followed by 100-200 more subcategories in Category:Mathematics. What do people think of this? Oleg Alexandrov 23:16, 5 September 2005 (UTC)

So my main objection to this category is this nonsense notion that an article shouldn't be both in a category and in a subcategory of that category. Following that ridiculous guideline, which it should be a high priority to delete ASAP, if an article is placed in Category:Mathematics in India, it ought to be removed from Category:Mathematics, and that would be silly. But the silly thing is the guideline, not the category. --Trovatore 05:32, 6 September 2005 (UTC)
Perhaps it would be better titled "Indian mathematics" instead of "Mathematics in India"; there may be use to put stuff like Vedic stuff in there. Dysprosia 08:46, 6 September 2005 (UTC)
I can imagine having a category for history of mathematics in India for Vedic stuff, and having this as subcategory of Category:History of mathematics. I struggle to see why present-day mathematics in India should be put in a separate category. Oleg's problem can be resolved by collecting Category:Mathematics in India, Category:Mathematics in United States, &c in something like Category:Mathematics by country. By the way, I quite like the guideline Trovatore mentions. -- Jitse Niesen (talk) 12:46, 6 September 2005 (UTC)
It seems to me that, if B is a subcategory of A, you may put an article in B for reasons involving a small piece of the article. If the rest of the article would by itself qualify as category A, then the article should stay in category A, otherwise not.
A slightly different issue is that a reader may be interested in seeing all articles in a category without having to know which subcategory to look in. If I browse Category:Mathematicians it's reasonable to expect to see John von Neumann without having to know that he was Hungarian or American or what century he worked in. --Trovatore 15:10, 6 September 2005 (UTC)Septentrionalis
The reason for the rule is that only 200 articles will be visible in a single category; Septentrionalis
Well, that should be changed. Let's get a feature request in. --Trovatore 22:07, 6 September 2005 (UTC)
Having tried to find things in large cats, I oppose the existence of larger ones. A cat of the thousand great mathematicians would be very slow to load and, by me, almost useless. Septentrionalis 22:23, 6 September 2005 (UTC)
The user interface needs some thought, to be sure. Possibly when a cat comes up very large, there should be some sort of page where the user decides what to do about it (view only subcats, split up by first letter, etc). But the classification question shouldn't be decided primarily by this sort of technical issue, much of which will change as servers get better, more users get broadband, etc. --Trovatore 22:32, 6 September 2005 (UTC)
and there are (thoughout history) a good many mathematicians even of v. Neumann's quality. Therefore Category:mathematicians includes by reference Category:American mathematicians Category:Hungarian mathematicians and Category:Game theorists and v. Neumann should be in all three of them.. Septentrionalis 21:46, 6 September 2005 (UTC)
As I see it, it is a guideline and not a hard rule, thus one may disregard it if one has a good reason. The first case mentioned by Trovatore could be a good reason; I'm less convinced by the second case. -- Jitse Niesen (talk) 22:18, 6 September 2005 (UTC)
Sure, I understand that it's not a hard rule. The problem is that too many editors follow it when they shouldn't. This is the reason, when I created Category:Determinacy, that I didn't make it a subcategory of Category:Set theory, even though it logically should be. I didn't want articles disappearing from the latter category just because they had some relevance to the former. --Trovatore 22:20, 6 September 2005 (UTC)

I asked the creator of this category to comment about it. Oleg Alexandrov 22:29, 6 September 2005 (UTC)

  • I appreciate that this is a rather odd category. I created it to clear the main menu in Category:India - something which has already been done for the United States and United Kingdom, and should be done for all countries (the problem with clearing most articles from a national category, but leaving a few awkward cases is that it highlights a few minor articles, whereas if any articles are to be left in the main national menus, they should be the most important). I don't mind what you do with this category, so long as you don't put the contents directly into the main India category. CalJW 22:32, 6 September 2005 (UTC)
I see. I would support renaming this to Category:Indian mathematics (per Dysprosia). I will post this on CfD today. Oleg Alexandrov 15:14, 7 September 2005 (UTC)
I posted this for deletion or renaming at Wikipedia:Categories for_deletion/Log/2005_September 7#Category:Mathematics in_India. I myself voted to delete it as I don't see any special need for such a category. Oleg Alexandrov 19:26, 7 September 2005 (UTC)

Table of Lie algebras & groups

I am vaguely thinking of starting an insane and hopeless task, and that is to create a page listing low-dimensional, non-supersymmetric Lie groups and algebras, thier properties, isomorphisms, topologies, etc. I despair, because this seems like a collossal project trying to describe a hopelessly tangled web of inter-relationships. I was irked because what I really wanted was a list of (examples of) infranil manifolds. Any suggestions on how to minimize the pain and maximize the gain? linas 15:19, 6 September 2005 (UTC)

There is a start to this project at the list of simple Lie groups; this still needs some work in filling in the properties of these groups. This will not help much if you want to know about nilpotent groups. R.e.b. 20:31, 6 September 2005 (UTC)

There is also table of Lie groups which I somehow blindly didn't see at first. linas 04:37, 7 September 2005 (UTC)

10000 math articles

The drinks are on me!

According to Wikipedia:WikiProject Mathematics/Current activity there are now 10029 mathematics articles and mathematician biographies. Now, around 500 of them are redirects, a bunch are arguably more physics or related than math, and a rather good chunck are stubs. Still, this is something of a milestone.

This also makes me think (again) that with so many articles, there is just not enough manpower to even check articles for vandalism and style, not to talk about the mathematical correctness and if articles are coherent rather than just a bunch of text put together by different contributors.

This is probably a good moment to think of where we are, and wonder what the future will hold. Oleg Alexandrov 22:59, 6 September 2005 (UTC)

Well, so far the pessimists have been wrong - badly wrong - about WP in general. It's bigger, and it's better, and articles are generally longer and better written. And more people come to look, and some stay to help. About the only thing that gets worse is the proliferation of tags (including unresolved clean-up). Charles Matthews 16:23, 8 September 2005 (UTC)
I think we should raise a glass in celebration. Paul August 16:54, September 8, 2005 (UTC)
Indeed! An excellent idea! A bit of celebration is in order. Cheers! linas 23:45, 9 September 2005 (UTC)
I am glad to see that Wikipedia is exceeding my previous expectations. When it came to joining this project, the choice was between here and Planetmath. I chose to work here, primarily for the reason of having all of the information in one place, instead of scattered across multiple sites with conflicting standards. What if there were separate sites "PlanetLinguistics", "PlanetZoology", "PlanetBotany", etc? I personally cannot tolerate this kind of fragmentation. I hope that people on Planetmath begin to feel the same way, and move their work over to this site to avoid duplication of effort. By the way, maybe with 10,000 articles we now have the leverage to ask for some tools to create commutative diagrams on Wikipedia (again: I mean the kind you can edit along with the rest of the article, not just uploading images). Wishful thinking ;-) - Gauge 21:32, 9 September 2005 (UTC)
What did the non-abelian dalek say? Charles Matthews 21:42, 9 September 2005 (UTC)
(Umm, did Charles have a little bit too much to drink?) linas 23:45, 9 September 2005 (UTC)
What did the non-Abelian Dalek say? linas 23:47, 9 September 2005 (UTC)
He says: "DOES - NOT - COMMUTE … DOES - NOT - COMMUTE" Paul August 00:00, September 10, 2005 (UTC)
Have we sunk so low? (And shouldn't that be K9? Daleks are organic.)
  • Q: What is purple and commutes?
  • A: An abelian grape.
  • (As told by non-mathematician) Q: What is purple and travels to work?
Hey, I didn't start this! Cheers indeed! --KSmrqT 23:57, 13 September 2005 (UTC)
Gauge, are you aware of our PlanetMath Exchange project? Paul August 23:17, September 9, 2005 (UTC)
I am aware of the PlanetMath Exchange. You can guess in which direction I prefer to port articles. Btw: What do you call a commutative semigroup?
A: A carpool. :-) - Gauge 02:14, 14 September 2005 (UTC)
If you start copying articles from Wikipedia to PlanetMath, you will get a commutative diagram. Oleg Alexandrov 02:26, 14 September 2005 (UTC)
That reminds me I forgot to comment on Gauge's idea of a commutative diagram tool. I've yet to contribute in any significant way to the category theory articles, (ostensibly one of my areas of expertise) because I can't work up the gumption to create those diagrams by hand. I would really love such a tool. Paul August 03:20, 14 September 2005 (UTC)
What happens when you get kidnapped by the mathematical mafia? Dmharvey File:User dmharvey sig.png Talk 02:24, 14 September 2005 (UTC)
I give up. What does happen? Paul August 15:44, 14 September 2005 (UTC)
They make you an offer you can't understand. Dmharvey File:User dmharvey sig.png Talk 22:37, 18 September 2005 (UTC)
Why are fields immoral? --Trovatore 23:05, 18 September 2005 (UTC)

lemma moved to lemma (mathematics)

The article lemma was moved to lemma (mathematics), with the former being made into a disamibig. I disagree with the move, as the absolute majority of pages linking there are about the mathematical term. And even if one agrees with the move, one needs to disambiguate the links, and having them point to the correct destination. I asked the person who did the move to comment here. Other opinions welcome. Oleg Alexandrov 21:58, 8 September 2005 (UTC)

It should be moved back. This should be a case of "primary disabiguation". The primary meaning is the mathematical one. Paul August 00:26, September 9, 2005 (UTC)
I agree - the mathematical meaning is likely to remain primary. Charles Matthews 07:08, 9 September 2005 (UTC)
I think we should maybe tread a little lightly. It's true that a large majority of the links are mathematical, but that could reflect the vigor of the mathematics project, our 10k articles and all that. If it's an important term for linguists, maybe they should get equal time in the dab page. (Like Alice, I only said "if"--I don't know enough linguistics to know how important a term it is.) --Trovatore 03:16, 9 September 2005 (UTC)
And the OED has another set of definitions entirely: ranging for "motto" to "basic definition" in lexicography. Go comment on that talk page, but we should not be rash. Septentrionalis 03:46, 9 September 2005 (UTC)
As the editor who moved the article, my main concern was to fix the lemma page that looked like this at the time. So the main purpose was to create a disambig page. I decided to move the page because (as others here have already pointed out) experts in other disciplines link to lemma with the same confidence that they know what it means. If that article is a {{disamig}} page, that will be noticed and fixed by Wikipedia:Disambiguation pages with links (because internal links should not go to dab pages). — That said, I anticipated that some might not agree with the move I made, so I created direct links to lemma (linguistics), but didn't fix articles to point to lemma (mathematics). In other words, it's easily undone if you don't like it, but please bear in mind that the WikiProject Mathematics may be a tad biased, and it's going to be more expensive to fix if you wait until the other disciplines realize that they've been had :-). Algae 06:27, 9 September 2005 (UTC)

I think it is probably better this way. --MarSch 11:12, 9 September 2005 (UTC)

The best solution is to have the mathematical sense as the main article, and use a disambiguation on that page (ie. See Lemma (disambiguation) for other uses). The mathematical sense is far more commonly used than the linguistics sense. Dysprosia 11:45, 9 September 2005 (UTC)
Dysprosia's solution is in line with the official policy: Wikipedia:Disambiguation#Page naming. Oleg Alexandrov 15:22, 9 September 2005 (UTC)
Well, that's assuming that the mathematical meaning really is the primary one. Is it? It's certainly my primary meaning, but then I'm a mathematician. I think we should hear from some linguists about how much they really use the term. --Trovatore 16:01, 9 September 2005 (UTC)

By the way, I suggest that this discussion (that is, all the above text) be moved to, and continued at, Talk:Lemma. That's a better place for people to find it in the future, and it's "neutral ground" so to speak. --Trovatore 16:41, 9 September 2005 (UTC)

Copied to Talk:Lemma
This discussion should follow.Septentrionalis 17:24, 9 September 2005 (UTC)

Connected, connectivity, etc.

For several months, I have been doing occasional clean-up work on the pages related to connectedness, connectivity, etc. Things are still a little messy, but I am not sure what to do about some issues. In particular:

  • The word "connected" has similar meanings in many fields of mathematics. Thus we have connected space, connected graph, and connected category. Do we want to consider "connected" as a mathematical term, independent of what field it is used in? Currently, there is a link to connected from List of mathematical topics (C). I consider this link to be somewhat inappropriate, since connected is a disambig that also points to nonmathematical usages. Should there be a page called "Connected (mathematics)"?
  • "Connectivity" is a slippery word. I have heard a number of mathematicians use it as a synonym for "connectedness". In graph theory, of course, it has a very precise meaning; thus, we have connectivity (graph theory). In some semi-mathematical fields, like cellular automata, image processing, and robotics, it seems to be used in the sense of how cells arranged in a grid are considered to be adjacent to each other. Thus, automata researchers might speak of "4 connectivity" (I guess). The word is used in the article Image processing, and I think this is what it means there, but I am not sure. In any case, there is no good place for that link to go; currently, it goes to connected. What should we do about this? Should there be a page about this meaning of the word, and if so, what should it be called? Maybe "Connectivity (grid)"? Is there a better word than "grid"? I have heard of "lattice connectivity". Is this the same thing?

Nowhither 00:01, 9 September 2005 (UTC)

In image processing on a square grid, a pixel is connected North, South, East, West (4-connected) to its neighbors. Many algorithms, such as flood fill (propagating a color to neighbors), offer the optional inclusion of the diagonal neighbors NE, SE, SW, NW (8-connected). --KSmrqT 03:38, 2005 September 9 (UTC)
Connectedness should be developed, since we prefer nouns. Connectivity can imply things about the topology. Charles Matthews 07:11, 9 September 2005 (UTC)
Good point about "connectedness". On the other hand, I think there is still a need for the connected page to be a general disambiguation, since there are pages that would not fit well with "connectedness", for example, Connected (album).
So, how about this scheme:
Connectivity is still a sticky issue. User:Kku has just made it a disambig, with the former content at connectivity (computer science). I agree that this is an improvement, but I am not sure if it is optimal.
I still think there needs to be an article about the definition of connectivity as it is used in image processing, cellular automata (?), and possibly robotics, parallel computing, etc. But I still do not know what to call it, or which of these fields use the same definition.
Nowhither 00:30, 10 September 2005 (UTC)
News flash: I wrote the connectedness article. See New "connectedness" article, below. — Nowhither 03:13, 12 September 2005 (UTC)


Do we have a specific math article on Omega? The specific one that states that mathematics can't be strung together and that discoveries are just luck? It also states that its goal is to try and find the halting possibility of a computer when faced with an infinite answer.

Omega doesn't "say" that; it's just a number. But Wikipedia does have an article on it: Chaitin's constant. — Nowhither 00:11, 10 September 2005 (UTC)

Math in the dock

See Wikipedia:Village_pump (miscellaneous)#Riemann_zeta_function. Oleg Alexandrov 03:56, 11 September 2005 (UTC)

At analytic continuation, some decent diagrams would help. For example of overlapping circles, showing how analytic continuation by re-expanding a power series can gain a fingernail-shaped area of definition. Charles Matthews 06:30, 11 September 2005 (UTC)
This kind of discussion gets my goat. It's absolutely ridiculous that people without prior experience in a field read an article about a topic in that field and then complain that it's the article's fault that they don't understand it. I know little to nothing about quantum mechanics or geology for example, but I wouldn't complain if I didn't understand the spin (physics) article or the Quantum Hall effect article. Wikipedia articles are not self-contained instructional works. Sure, an article can try and explain as much as reasonably possible for someone with some assumed knowledge, but the important fact remains that Wikipedia is a reference work and not an instructional work (compare Wikibooks). This is doubly inappropriate for mathematics works, where the very nature of the topic depends on having assumed knowledge to understand deeper and more complex work. Dysprosia 07:40, 11 September 2005 (UTC)
I'm not exactly fond of the comment or commentator. There aren't many mathematical articles where the exposition is perfect; nor is the coverage anything like complete in 'core' topics (whatever those are). So the chances are that matters can be improved. Charles Matthews 08:26, 11 September 2005 (UTC)
Oh, absolutely, I'm not disagreeing that pages can be improved -- many of the math articles could do with improvement from what I've seen, but it's the sort of "I don't understand the article, so it must be a bad article" attitude that irritates me. Dysprosia 09:00, 11 September 2005 (UTC)
As one of the laypeople who responded to that "survey", I'd like to chip in. Please understand that I mean this as constructive criticism and not as bashing or saying that you guys are going about things in the wrong way -- on the contrary: I'm impressed that we've got such thorough coverage of these topics in the first place.
Of course not every math article is going to be 100% comprehensible to the layperson. On the other hand, it is possible for every math article to make clear to the layperson why its subject is important. Not everyone who reads that article will be a mathematician. A large number will presumably be people who were reading about something else that mentioned the Riemann Zeta Function and want to get at least a basic sense of why the Riemann Zeta Function is such a big deal.
I've got a 4-year college degree, including two years of math: so probably a stronger math background than 90% of Americans -- and I still get lost in the first two sentences of most math articles on Wikipedia. Anyone in this wikiproject knows more math than I, and that's necessary for this project to be possible. On the other hand, it may make it more difficult to see things from the perspective of someone who doesn't already have a firm grasp of the concepts you're discussing.
If a layperson doesn't understand an article, it doesn't mean it's a bad article. It may, however, be an indicator that there are areas of the articel that could still be improved. I think it would be possible to improve the comprehensibility of many of the math and science articles on this encyclopedia. If I knew anything about the subjects, I'd work on it myself -- as it is, I'd be happy to give any assistance I can to anyone in this wikiproject who is interested in attempting to do so. -- Avocado 14:54, September 11, 2005 (UTC)

I think both Charles, Avocado, and Dysprosia have very good points. A great many math articles are written for an audience which knows at least as much as the person writing the article. In many cases there is no motivation, no intuitive explanation, no gradual development from easy to complex, no pictures, no examples, and the list can go on. If one would teach in college with the same attitude, one would get quickly fired (well, ideally :)

However, there is only that far one can go in making a topic acessible. For example consider the meromorphic function article, which now has a {{technical}} template slapped upon. If you know anything about the complex plane and about functions, you should understand from the examples and the picture that a meromorphic function is roughly a fraction of two functions, with the denominator going bad every now and then. However, if you say that you don't understand the statement:

In complex analysis, a meromorphic function on an open subset D of the complex plane is a function that is holomorphic on all D except a set of isolated points, which are poles for the function.

then that's your fault. You cannot possibly understand meromorphic functions unless you know what holomorphic functions and poles are. Oleg Alexandrov 17:30, 11 September 2005 (UTC)

"A meromorphic function is roughly a fraction of two functions, with the denominator going bad every now and then."
I understand that that phrase is probably an oversimplification and not 100% accurate, but it makes it a million times more clear to me what a meromorphic function is, even without my knowing much of anything about the complex plane. A few more plain-english explanations might be helpful. I don't need to understand meromorphic functions any more than I need to understand the internal workings of my cellphone's AC adapter, but having an idea of what they are or what makes them interesting is possible. -- Avocado 17:54, September 11, 2005 (UTC)


Please note that there are now 10,000 math articles on WP (making it as large as Wolfram's mathworld, it seems), and that maybe 80% of these articles require at least a math major, and many require considerable post-graduate studies. Its impossible to make these 80% understandable to non-mathematicians; even math professors trained in one field might not understand articles written in another field. So what can we do?
I suggest a new category, Category:Overview of mathematics, that would contain articles from any branch of math, but with the requirement that these articles be comprehensible (and enjoyable) by anyone with no more than a year or two of college math education. For example, what's knot theory and why would anyone care? How about soap bubbles as minimal surfaces? Of course chaos belongs there, as does gravity, and something along the lines of Riemann zeta revealed. Furthermore, these articles could be written as "educational trampolines", starting at the most basic level, e.g. torus, and rocketing the reader into very advanced topics (the torus opens the door to things like Albanese variety) if the reader is diligent enough. In some sense, Category:Overview of mathematics would be the math version of "featured articles", with the bar set maybe only a little bit lower. linas 17:39, 11 September 2005 (UTC)
(Corollary: "too technical" labels will be unceremoniously stripped from articles that are not in Category:Overview of mathematics, e.g. the meromorphic function article.) linas 17:48, 11 September 2005 (UTC)

It sounds good to me. I do think we should be careful that this solution not become a way to remove all pressures to add intuition and motivation, though. In my own case, I know that my Prewellordering article is guilty of the offenses Oleg mentions, particularly the Prewellordering property section.

The other side of that is that it is better to have something than nothing, I think. Prewellordering needs to be motivated, but for me at the moment finishing the Determinacy article is a higher priority, and I do have non-Wikipedia tasks as well. In the mean time I think it is better that there be an unmotivated article on the prewellordering property than none at all. --Trovatore 18:00, 11 September 2005 (UTC)

In theory it would be possible for a high school student to learn linear algebra from the articles on wikipedia, in practice this wouldn;t work, because s/he wouldn't know were to start and in what order to read the articles. So we could create an article called learning linear algebra. On the articles we could slap some prerequisites such as linear algebra and comples analysis which link to those articles. (Unsigned comment by User:R.Koot 18:02, 11 September 2005)
No. Wikipedia is a reference work, not an educational one. Learning mathematics from an encyclopedia would be extremely difficult, because the encyclopedia material is not geared for learning, it is geared to be a reference work. Wikibooks is for educational material. Dysprosia 23:20, 11 September 2005 (UTC)

I can find nothing above with which I disagree ;-) Per Euclid, There is no royal road. But we need to keep trying to make the road as short and smooth as possible. Paul August 18:53, September 11, 2005 (UTC)

Having math overview articles aimed somewhat lower than the normal math articles is a good idea. My suggested "connectedness" article (see "Connected, connectivity, etc." above) could be one of these. However, I must agree with Dysprosia, that educational works belong in Wikibooks. In fact, the linear algebra tutorial suggested by R.Koot has already been started there; see wikibooks:Linear algebra. — Nowhither 00:31, 12 September 2005 (UTC)

I may as well throw in my 2 cents: I have been developing an idea that certain topics in mathematics have a certain intrinsic minimum complexity which cannot be reduced in any exposition. In this sense, one can either present the material as simply as possible while retaining accurate content, or lose accuracy for the sake of readability. I agree with Linas that the current Riemann zeta function article may in fact be too simple rather than not simple enough; an accurate description of the zeta function and its properties is complicated business, no matter how you present it. I tend to write articles as reference works aimed at graduate students and researchers. I recommend (to those who are interested) the creation of an article Riemann zeta function (overview) or something similar for those who want a less technical exposition. There is certainly room for both perspectives (research-oriented and pedagogical).
Also some nitpicks that I have with the current article:
  1. The Easier proof for the layperson section really belongs in another article if we are to make this article the more technical one. The technical proof is shorter and more elegant.
  2. The "Importance of the zeros" section needs elaboration and appears in an odd place (before "basic properties"?). It should be moved further down into the article.
  3. I wonder if the physics applications of the Riemann zeta should have its own separate article? I have a feeling that there are enough applications just in physics to warrant such an article...
  4. If this article does become the more technical one, we should place a warning at the top pointing readers to the "easier" version as well.
- Gauge 02:34, 12 September 2005 (UTC)

So what's the plan?

I like Linas' suggestion at least in principle (with the caveat that it not become an excuse to avoid adding motivation to articles). I'd suggest further that there be a uniform naming scheme for the simpler articles, say Foo (introduction) or Foo (elementary) for the beginners' version of Foo. But it does seem like something of an "unfunded mandate"; I'm not personally volunteering to produce these articles for the hundreds if not thousands of topics that'd need them. Any further thoughts? I hate to see the matter just dropped, without a clear decision. --Trovatore 20:13, 13 September 2005 (UTC)

One more idea

As a less radical measure, how about updating just the introductions of some of the math articles to be more accessible. For instance, something to the effect of:

The Riemann Zeta Function is a mathematical function discovered by Whatever-his-first-name-is Riemann in 1822. It is important in number theory because it demonstrates some property of prime numbers, as was proven in 1903 by whoever.
< template of some sort >
What follows is a technical discussion of the properties of the Riemann Zeta Function. This discussion assumes familiarity with meromorphic functions, the Euler Product Formula, basic forcing, and whatever else.
< / end template >

-- Avocado 21:29, 13 September 2005 (UTC)

It's all a question of perspective

From the back-jacket information for Itay Neeman's book on The Determinacy of Long Games, which I will likely cite:

The book is largely self-contained. Only graduate level knowledge of modern techniques in large cardinals and basic forcing is assumed.

--Trovatore 18:41, 11 September 2005 (UTC)

That's a good one! Only very basic forcing is assumed, right? As far as I am concerned it means that I will have no clue whatsoever about the very first section in the book. :) Oleg Alexandrov 23:04, 11 September 2005 (UTC)
That's cute. FWIW, I know a Ph.D. student who did his dissertation on forcing. Apparently the first question at his defence was, "So, what's 'forcing'?" He said he immediately knew he was going to pass. — Nowhither 03:00, 12 September 2005 (UTC)

New "connectedness" article

As suggested above in a couple of places, I have written a new article: connectedness. This is supposed to be an overview of mathematical uses of the term (and similar words), written at a somewhat lower level than most mathematical articles. I would be interested in hearing what people think about:

  • Is this a good article to have?
  • Is it written at a low/high enough level?
  • Should there be other similar articles?

By the way, I also put a note linking to the new article in connected, which is a general (non-mathematical) disambig. And I removed "connected" from the List of mathematical topics (C) and replaced it with "connectedness". And ... I'm still wondering what to do with connectivity.

Nowhither 03:12, 12 September 2005 (UTC)

Looks useful to me; but, like most readers at this page, I cannot tell what it would look like to a non-mathematician. You should take this question to the Village Pump, or, despite the fact you actually want cmments, WP:RfC

Was Bertrand Russell Welsh?

And, speaking of RfC, one of the topics there is:

Was Bertrand Russell Welsh and does he belong in Welsh Wikipedia:categories? (He was born in Monmouthshire, and lived there until his parents died - when he was four.)

I'm not making this up; if anyone has an opinion on the matter (I did) do go share it with Talk:Bertrand Russell; maybe we can drown out the various contending nationalisms. Septentrionalis 22:46, 12 September 2005 (UTC)

How important is a list of publications?

Currently, List of publications in mathematics has at the bottom 31 mathematics categories. Some explanation for that is here. The whole thing seeems to be an effort by APH as part of Wikipedia:WikiProject Science pearls. I truly doubt that there is any article under the wiki Sun so important as to be included in that many categories. Oleg Alexandrov 06:24, 13 September 2005 (UTC)

I agree; this is an inherently PoV effort to make a list do the work of a category. Unmaintainable, controversial, naturally incomplete - and if completed, useless. AfD? Septentrionalis 03:28, 14 September 2005 (UTC)
AfD, seems a bit drastic. I don't think I could support that. Lists have several well discussed advantages over categories, for example they can be annotated, as this one is. (By the way just out of curiosity, a show of hands, how many people know that VfD has been renamed?) Paul August 04:49, 14 September 2005 (UTC)
I don't want that artilcle deleted either, just put in two to three relevant categories and link to it from other places. Oleg Alexandrov 04:56, 14 September 2005 (UTC)
I know what you are implying when mentioning AfD. I agree with renaming the VfD but I think the decision was taken very fast and without public consultation. Uncle G, can you clarify us in here? (Uncle G's bot did the move.) Oleg Alexandrov 04:56, 14 September 2005 (UTC)
I sort of agree with Paul the list could be valuable. Right now IMO it's overly weighted to publications of historical importance; what's really more needed is a bibliography of reference works and textbooks. Maybe with BibTeX entries too? That'd be great.
On the other hand the book reviews that make up much of the content could be problematic. I just wrote one today for Kunen's set theory book, but it occurs to me that a book review is almost on its face original research, or at least original journalism. Still, WP has lots of 'em. --Trovatore 04:58, 14 September 2005 (UTC)
I'd like to respond to the ideas above. First, I'd like to point out that I also think that the use of a list is problematic. I see it as an initial phase before creating an article for every publication and connecting them using categories (See more details at the project description). Note that in the next phase the problem that bothers Oleg will be solved too. An article about logic won't be in the topology category. The description of the publication shouldn't be an original research. Most of the times, something quite similar to the publication abstract will do. BibTeX entries is a great idea. APH 05:37, 14 September 2005 (UTC)
Isn't there a larger issue here? What we have on List of publications in mathematics, especially near the bottom, is a list of papers. But mathematical research papers are being published at a rate of something like 100 per day (rough estimate — and that's only the ones that make it into Math Reviews). It is ridiculous to expect to sort through these and point out those that ought to be listed, whether in a big list, as separate articles in a category, or whatever. The problem with this page is not misuse of categories, or anything like that, but that it is aimed at an impossible task, the magnitude of which boggles the mind. The page very badly needs a more focused purpose. — Nowhither 01:16, 16 September 2005 (UTC)

Science pearls

Hello, Please notice this project. I hope that the List of publications in mathematics, List of publications in statistics and List of publications in computer science will be adopted by the mathematics project. Thanks,APH 06:48, 13 September 2005 (UTC)


It seems to me that the article on logical converse is incomplete. It has the schoolbook definition of the converse, which is that the converse of a statement of the form (AB) is the statement (BA). But I think that "converse", as the term is used by mathematicians, is actually a more subtle and complex concept. I've put some simple examples at Talk:Converse (logic).

I think that if we actually look at examples, we'll find all sorts of different forms that the converse can take, and that this information should be incorporated into the Converse article.

I hope people will assist me in this. -- Dominus 13:32, 14 September 2005 (UTC)

Boolean algebra, redux

Once again someone has been trying to rewrite the Boolean algebra article based on the preconception that it's about the logical calculus sometimes called "Boolean algebra". I'm afraid I got into a mini-editwar with him; he got tired of it and went to write his own article called Boolean algebra (basic concepts). I think he wants to rename Boolean algebra to Boolean algebra (complex theory).

I think there should be two articles, but I see dark clouds on the horizon with this editor. He doesn't show any signs of wanting to believe me that a Boolean algebra is something like a group or ring, rather than a "complex" version of what he thinks of as "Boolean algebra" as a mass noun. I'm worried that he'll try to incorporate material about the algebraic-structure notion into his "basic" article, which will only confuse the issue. I could use some help here, guys.... --Trovatore 21:26, 14 September 2005 (UTC)

At the risk of being contrary, the first sentence of Boolean algebra suggests to me that it would rather be in an article called Boolean algebras.Hv
Well, see, here you run into a Wikipedia convention. All such articles have singular titles. There's an article called orthogonal polynomials, but that's only because there's no such thing as an "orthogonal polynomial" in isolation. --Trovatore 23:51, 14 September 2005 (UTC)
Certainly the current link to Binary numeral system is a poor substitute for an article that would talk about the (singular) Boolean algebra that high school mathematicians and computer scientists have to deal with. Hv 23:47, 14 September 2005 (UTC)
Yes, that's true; that article needs to be written. If we could only agree on what it should be called.... --Trovatore 23:51, 14 September 2005 (UTC)

My five cents (yeah there's been some inflation): if we have a decent article on Boolean algebra as envisaged by StuRat et al (i.e. currently named "basic concepts"), then that should get primary status as Boolean algebra, simply because it's the one more likely to be searched for by a general audience; and there should be a dab notice on that pointing to something like Boolean algebra (algebraic structure). Dmharvey File:User dmharvey sig.png Talk 23:57, 14 September 2005 (UTC)

Hm, wouldn't be the solution if I were God. But if it keeps this problem from recurring I s'pose I can live with it. Still leaves open the question of what should really go in the article, though. How is it different from propositional calculus? Just by adding Boolean search terms & such? --Trovatore 01:07, 15 September 2005 (UTC)
I think the solution is to merge Boolean algebra (basic concepts) into Boolean logic; the latter is not very good, and is just shy of being a stub. Septentrionalis 14:48, 15 September 2005 (UTC)
I don't think that's a natural fit. Boolean logic is about a correction to Aristotelean logic, which was overly complicated because it didn't allow propositions to be vacuously true. So it doesn't really make sense to talk about Boolean logic except when you also talk about Aristotelean logic, and we have no need to to that for this subject. --Trovatore 15:00, 15 September 2005 (UTC)

I think both things are and should be called "Boolean algebra" with at least one being of the form "Boolean algebra ( … )". I suggest that we set aside for the moment which, if either, should simply be called "Boolean algebra". Let's assume for the moment that both articles need parenthetical disambiguation, and try to decide what they should be.

  • For the 6-tuple one (A, +, ·, ~, 0, 1) should it be:
  • mathematical structure?
  • algebraic structure?
I'm not completely happy with this one because I also (perhaps not alltogether correctly) think of this structure as an order theoretic, a set theoretic and a logical structure as well.
  • structure?
  • object?
  • For the the article about, in DmHarvey words, " the art of manipulating truth values and logical connectives", should it be:
  • methodology?
  • logic?
Of the two I guess I like this one best.
(By the way this looks like a good online reference for this article.)

Paul August 22:02, 15 September 2005 (UTC)

Yeah, I also have noticed the problem with "algebraic structure"; e.g. one of the properties of BA's that should be addressed in the article is completeness, which is not definable algebraically. OTOH that's a bit of a nit; it's not as though anyone would object to addressing completeness in an article called "Boolean algebra (algebraic structure)". I agree "logic" is better than "methodology" for the other concept but I'm not entirely happy with it. --Trovatore 23:13, 15 September 2005 (UTC)
How about cutting the Gordian knot (for the first concept) with Boolean algebra (structure)? --Trovatore 18:58, 18 September 2005 (UTC)
Wow this is hard. I don't like Boolean algebra (structure) because "structure" is too vague -- it sounds like it means "structural aspects of Boolean algebra", like Economy of China (structure). I liked one of the earlier suggestions: Boolean algebras, although this might be against WP naming conventions (???). Perhaps Boolean algebra (mathematical entity) or Boolean algebra (set with operations)? Arrgggh. Dmharvey File:User dmharvey sig.png Talk 19:48, 18 September 2005 (UTC)
The situation's not that bad--we don't have to go suggesting spiritual emanations, which is what "entity" makes me think of. I'm ok with either "mathematical structure" or "algebraic structure". I just thought maybe it could be made less wordy and more inclusive by dropping the adjective. --Trovatore 19:57, 18 September 2005 (UTC)
I like the "Boolean algebras" name. In cases where the singular has come to mean one thing and the plural something entirely different (maybe "datum" and "data" or "Earth" and "earths" would be good examples), I think it should be permissable to use a plural name. StuRat 20:00, 18 September 2005 (UTC)

I see that one of Paul's suggestions I overlooked was Boolean algebra (object). That's not bad, though I think I still prefer "mathematical structure". I don't like the plural because it (1) suggests that these things are somehow "alternative versions of Boolean algebra" and (2) is not in line with the naming given to other structures, like Group (mathematics). --Trovatore 20:07, 18 September 2005 (UTC)

If we are to use strictly singular, shouldn't that have been Group (mathematic) ? StuRat 20:31, 18 September 2005 (UTC)
Perhaps Boolean algebra (mathematical object)?. Dmharvey File:User dmharvey sig.png Talk 22:36, 18 September 2005 (UTC)
I could live with that. I prefer "mathematical structure", though. --Trovatore 23:13, 18 September 2005 (UTC)
Yep, "mathematical structure" works for me too. Dmharvey File:User dmharvey sig.png Talk 23:22, 18 September 2005 (UTC)

Indicial calculus

Indicial Calculus claims that it is "the calculus used to extract root indices of order x, where x is an element of a Galois splitting field for a given polynomial equation of ductivity ." Does this ring a bell to somebody? The reference to "Little Bride Bonnie (1859-1941), a German mathematician known for early work in group theory" made me suspicious, and a quick search on MathSciNet and Google didn't yield any results. -- Jitse Niesen (talk) 21:18, 15 September 2005 (UTC)

The intro, as phrased, is nonsense: whatever a root index is, its order shoulc be an ordinal, not an element of a Galois field. Constructing a cube of side e (next paragraph) is trivially equivalent to constructing a segment of length e. I've never heard of ductivity, either. Septentrionalis 01:21, 16 September 2005 (UTC)
A mathematician Little Bride Bonnie is mentioned there. From what I know, Bonnie is a girl's name. Equivalently then, the name of this German mathematician is Little Bride Mary if you wish. BJAODN. Oleg Alexandrov 02:06, 16 September 2005 (UTC)
No paper by Hinkle is in Jahrbuch über der Fortschritte der Mathematik for 1899-1901. Hoax. AfD, IMO. Septentrionalis 05:00, 16 September 2005 (UTC)
Bonnie (also spelled bonny) means pretty, as in "my bonnie lass" and brides are often referred to as bonnie (search Google for "bonnie bride" or "bonny bride"). Paul August 05:47, 16 September 2005 (UTC)
I did some digging and posted my impressions on the talk page. Especially, the index calculus algorithm is frequently cited in cryptography. Given the existence of that page, even if Indicial Calculus is meant to be legitimate its page should not exist. --KSmrqT 11:49, 16 September 2005 (UTC)

I decided to replace the article by a redirect to cyclic group, which is where index calculus also redirects to (KSmrq found this out, thanks). Saves a trip to AfD. -- Jitse Niesen (talk) 14:39, 16 September 2005 (UTC)

List of mathworld's math articles

See discussion at Wikipedia talk:Requested articles/mathematics#MathWorld?. Comments welcome. Oleg Alexandrov 03:20, 16 September 2005 (UTC)

Is a high school math teacher who got a prize for undergraduate paper notable enough?

... We will find out. Wikipedia:Articles for deletion/Mark Schmitt. Oleg Alexandrov 02:01, 17 September 2005 (UTC)

Note for Lie algebra specialists

Anybody heard of the "corank" of a Lie algebra? An anon replaced "rank" with "corank" at Affine Lie algebra, and I don't know if that's correct or not. Oleg Alexandrov 16:06, 18 September 2005 (UTC)

I'm watching that one, I think that's rigt, that's what makes it affine. But not sure; I was going to read on the topic (quantum groups) this summer, but got distracted. Maybe next summer. Its a pretty advanced topic, mostly just string theorists live there. linas 04:41, 20 September 2005 (UTC)
The "corank" here refers to the generalized Cartan matrix, the dimension of its null space. However, neither choice seems to agree with the definition already in place at the end of the Kac-Moody algebra page. The symmetric factor of the matrix is there required to be positive semidefinite, which does not place such a stringent restriction on either rank or corank. Even knowing almost nothing about the topics it appears that something is amiss. If someone wants to dig further, a standard reference book seems to be Victor G. Kac's Infinite-Dimensional Lie Algebras, 3/e, CUP 1990, ISBN 0521372151 (paperback: ISBN 0521466938). Or ask your friendly neighborhood string theorist. --KSmrqT 06:53, 20 September 2005 (UTC)

Check those links

Just a reminder that when you've guessed the name of an article you're linking to, and it comes up blue and you save your edit, it's worth clicking through to those links and seeing if they say something sensible and relevant to the meaning you have in mind.

I happened across a page called complete Boolean algebra that had some trivial nonsense in it, nothing to do with CBAs, yet it was linked to from complete lattice.

Another possibility is that the link from "complete lattice" was originally red, and then someone came along and filled in the incorrect "complete Boolean algebra" page. To protect against this sort of thing, click through to your redlinks and add them to your watchlist (yes, this works). --Trovatore 17:32, 19 September 2005 (UTC)

One can also check Wikipedia:WikiProject Mathematics/Current activity for incoming stuff. Oleg Alexandrov 04:35, 20 September 2005 (UTC)

What is an Isometry?

Our articles Isometry and Metric space have different definitions of isometry. The former requires an isometry to be onto, the latter does not. There is a discussion at Talk:Metric_space#Isometry, about which is more standard, and what we should do about it. Please share your thoughts there. Thanks Paul August 16:38, 22 September 2005 (UTC)

Unicode in math articles

The bot User talk:Curpsbot-unicodify has started crawling the math pages and converting html greek characters, such as γ, into glyphs that are hard to work with (although they render the same way). I don't think this is a good idea for math formulas and math expressions, although I support it for the other cases (people/place names, etc.) I'd like to see some sort of majority consensus developed on this, for or against, at User talk:Curpsbot-unicodify. linas 14:56, 24 September 2005 (UTC)

Sorry, I don't see the problem, can you please elaborate?
You aren't forced to enter Unicode characters, you can still use the HTML entities, if you don't have keyboard access to the special characters. And the Curpsbot-converted characters look in the edit field the same as both style of characters look in the article.
Pjacobi 17:53, 24 September 2005 (UTC)
That's a WYSIWAG approach--"what you see is all you get". For mathematics it's better to preserve the meaning of symbols in the source code, not just their appearance. HTML doesn't really do that very well, but it's better than Unicode. --Trovatore 18:04, 24 September 2005 (UTC)
WYSIWYG: Screen readers for the blind, last I checked, handled &gamma; a lot better than unicode. Nahaj 18:16, 24 September 2005 (UTC)
I added a comment to the effect that if we had replaced such strings in the editable code as "&gamma;" by the more accurate "<math>\gamma</math>", then there wouldn't be a problem. -- Arthur Rubin 21:40, 24 September 2005 (UTC)
If screen readers really do have trouble with unicode, then I will oppose conversion to it. - Gauge 00:09, 25 September 2005 (UTC)
As I understand it, it isn't Unicode per say that is the problem... It is a matter of how many characters (of the many thousands) have speakable names listed in the screen reader's tables. Someone should check this... my information is a few years old. Nahaj 01:40, 25 September 2005 (UTC)
The age of my information may be moot. Many handicapped folk are running older software for financial reasons. Nahaj 21:38, 30 September 2005 (UTC)

First of all, the bot has not started systematically crawling the math pages. It only happened to crawl the Wess-Zumino-Witten model article because that was on a list of requested articles sent to me by User:Beland, and he only wanted that article processed because it contained two spaces instead of one in a [[Riemann  sphere]] link (the bot also does this, although its main function is Unicode conversion). The bot is mostly concentrating on eastern European pages and such at the moment (for instance, see this edit to Russian grammar).

For the time being, I have edited the bot code to skip any page that contains a <math> tag. It might revisit them later with a flag set to avoid processing Greek letters. In the long run, however, you might be better off to use <math>\gamma</math> instead of &gamma; as Arthur Rubin suggests, because the visual appearance of and γ is usually quite different, and if you're arguing that the visual appearance of γ is confusing in the editor window then it's surely equally confusing in the reader window (displayed browser page). Or perhaps even more confusing, since readers are sometimes less sophisticated than editors and the two different-looking gammas might be mistaken for different symbols.

By the way, I presume you folks know that &epsilon; &phi; (ε,φ) are not the same things as \epsilon \phi ( or ε,ϕ)? According to the TeX book and respectively, the latter are supposed to be "lunar" epsilon and "unbroken-circle" phi with bar extending above the circle, although the glyphs used in various fonts may render them identically (as seems to be the case under Windows XP, for instance). See [18] and compare U+03B5 vs. U+03F5 and U+03C6 vs. U+03D5. This is another argument against using HTML entities when TeX math symbols are intended. -- Curps 20:21, 25 September 2005 (UTC)

PS, also, &asymp; and \asymp refer to entirely unrelated symbols (a naming issue), although the <math> tag doesn't seem to recognize \asymp.
Warning: ϕ (the unicode &#x3d5) does not display, at least on this computer, although all the rest of Curps' post does, including \phi. (Neat trick with the &amp; though.) Also, the <math> epsilon and the unicode epsilon(&#x3b5;) are not identical; the latter is almost identical to &epsilon. (This is a library machine using Windows, so I can't comment on what else it's doing.) Septentrionalis 01:06, 26 September 2005 (UTC)

Commuting diagrams?

What are the prospects for commuting diagrams in TeX on WP? Most pages that have them seem to have custom-generated PNG's. My attempts to create a native diagram result only in ugliness:

and a triangle:

The markup is complicated too ... Any better way of doing this? linas 00:01, 26 September 2005 (UTC)

Yes, it would be nice if the powers that be included some diagram package into the wiki math code. I generate PNG's using a program called textogif and just upload them. It is fairly fast and painless once you have it all set up. Check out my page on Wikimedia Commons. I have some minimal set of instructions there. -- Fropuff 16:26, 26 September 2005 (UTC)
I thought one can use xypics to create diagrams. This is a LaTeX package. So, all needed is for the Wiki TeX dialect to support this package. I also wish that Wiki TeX also supported the amsart package, as when we copy articles from PlanetMath as part of the WP:PMEX project, often many TeX symbols are not recognized. Oleg Alexandrov 17:36, 26 September 2005 (UTC)

Merging manifold and manifold/rewrite

The article manifold has been rewritten at manifold/rewrite. Manifold/rewrite has had around 225 edits since June 19 when Jitse started it as a text in his sandbox to offer some constructive suggestions to the arguments at talk:manifold. Now the rewritten article looks nice and needs to be merge into manifold, which itself underwent around 58 edits since June 19. The big question is, how to merge them? One can merge the edit histories, see Wikipedia:How to fix cut and paste moves, but it could be a mess. The only other choice is I think to give up on the history of one of the two articles. What should be the right decision? Let us discuss this at talk:manifold/rewrite. Oleg Alexandrov 04:27, 26 September 2005 (UTC)

Comments requested on new proposed math stub names

See Wikipedia:WikiProject_Stub_sorting/Proposals#More_Math_stubs. Oleg Alexandrov 00:51, 27 September 2005 (UTC)

Controversy over the birthday paradox article

At Talk:Birthday paradox it is being proposed to delete from the article the section on Paul Halmos' view of the matter. That is the only section that takes the reader beyond the stage that any freshman who thinks the problem through would figure out. It's a fairly short section. Three Wikipedian support deletion; only I have opposed it. Would mathematicians please comment at Talk:Birthday paradox? Michael Hardy 22:41, 2 October 2005 (UTC)

Oh: It's the part labeled "long, windy, not needed". Michael Hardy 22:42, 2 October 2005 (UTC)
... and now I've changed the title of that section of that long talk page, to make it easier to find. Michael Hardy 22:44, 2 October 2005 (UTC)

New article on anti-Cantor newsgroup participants

Dave Petry (I'm 99% sure it's he) has started a new article called Controversy over Cantor's Theory. Dave's been showing up from time to time on sci.math and sci.logic for some years with variations on this theme--set theory is "mythological" and has nothing to do with "reality" as defined by things that can be observed on a computer. He's not stupid or crazy, just wrong; it's sort of amusing how he says (on the article's talk page)

This article is an attempt to give an overview of the more sensible views on this topic

because the less sensible views are those of certain individuals at least one of whom has a WP article about him (Archimedes Plutonium).

Anyway the project itself is perhaps worthwhile; I don't see anything wrong with having an article about philosophical views hostile to the use of set theory in mathematics, and how they have evolved, if indeed they have, as a result of the "computer age". This particular article in its current form, though, is very much OR and very POV. I hope others will take a look at it and figure out how to fix it or whether it's worth fixing; I really should be working on that paper.... --Trovatore 04:12, 3 October 2005 (UTC)

Well, it's rambling, unsourced, POV and apparently quite ignorant of work in areas such as domain theory that do argue for replacements of set theory for purposes of theoretical computer science. Move to criticisms of set theory, and cut down by about 80%, I'd say. Charles Matthews 21:36, 5 October 2005 (UTC)
The point of the article is to document the debate that has been taking place on Usenet over the past decade and a half at least, and to show that the current debate is really not much different from the debate from the early part of the twentieth century, except that the computer revolution does give people a new way of thinking about mathematics. As I point out in the article, the current anti-Cantorians are not pure mathematicians mostly, but rather people who have applied mathematics. I don't think you guys (Mike Oliver and Charles Mathews) understand what the debate is all about, and hence you guys are not really qualified to judge the article. It is "unsourced" currently, as it is still a work in progess. If you want to add a link to domain theory, that would be just fine -Dave Petry 5 October 2005
Let me add some comments especially directed to Mike. First, we know that quite a few very talented mathematicians have objected to Cantor's Theory. The names Kronecker, Poincare, Brouwer, Weyl, and Bishop usually are mentioned in this regard. Would you say that those guys are just plain "wrong". Are they more wrong or less wrong than me, and why. But furthermore, do you think those guys would say that the article I wrote is "original research". Although I have given the subject a slightly different perspective (invoking computers), I think those earlier mathematicians would recognize almost everything I have written as being very close to their own ideas. 03:01, 6 October 2005 (UTC)
OK, there's two separate points here, correctness vs original research; let's keep them separate.
Correctness: I actually agree with you about the applicability of the scientific method to mathematics. I think you're wrong that the appliction of the method militates against set theory. In fact, set theory makes refutable predictions in a Popperian sense, and they have thus far all been confirmed. And they can be formulated in terms of the computational world you discuss. I suspect that you may have a prejudice that a scientific approach requires restricting attention to the physical world.
Historical figures: All those you mention have made important contributions. That doesn't mean they weren't wrong about some things too, and I think they were. (Kronecker's a separate case; I tend to think of him as actually a bad person, for his persecution of Cantor, but it could be that my view of this is filtered through Cantor's depression and paranoia, plus (as I point out at every opportunity) I'm not much of a historian.
Original research: Let's be very clear that this part of the discussion has nothing to do with the merits of your ideas. The fact is that they appear to be your own personal observations. Even the language you attribute to the "anti-Cantorians" is in many cases almost identical to your own newsgroup essays. Yes, I think all the historical figures you mention would call your page "original research", once they understood the Wikipedia definition of the phrase. Hint: Just because it's OR here, doesn't mean a journal couldn't reject it for not being original. See WP:NOR for more information. --Trovatore 03:45, 6 October 2005 (UTC)
On this topic, you are not an expert. You don't understand the views of those you disagree with. I hope you don't succeed in keeping my article out of the wikipedia.
Have you read the WP:NOR correctly? Fortunately, Wikipedia isn't about who is/isn't an expert, but rather about who can give some source to backup his claims. And no, USENET is not a reliable source of mathematical knowledge. Samohyl Jan 14:32, 6 October 2005 (UTC)
We can have an article about criticisms of set theory, as we have one about criticisms of Wal-Mart. It must conform to WP's standards, that's all. Charles Matthews 21:03, 6 October 2005 (UTC)
For the historical "anti-Cantorian" arguments, I can easily give sources, and I intend to(the article is not finished). Part of the purpose of the article is to document the Usenet debate about Cantor's Theory, and to show the similarity of that debate with the historical criticisms of set theory. It would be a stretch to say that showing the similarity of the arguments is "original research". And likewise, the Usenet is most definitely a reliable source for knowledge of the debate taking place on Usenet. I understand why the wikipedia doesn't allow original research, but I don't think the intent is to keep articles like mine out. I absolutely do not accept Charles Matthew's butchering of my article, and eventually I plan to revert to a previous article.
Certainly there are other controversial topics in wikipedia, for example, Matthews mentions criticisms of Wal-Mart. So how does wikipedia stop "combatants" from sabatoging each other's articles? 23:31, 6 October 2005 (UTC)
In wikipedia, no single editor owns or possesses an article, thus the possessive in the phrase "each other's articles" makes no sense. With very few exceptions, every editor has equal rights to edit any article, however they see fit. It is the miracle of Wikipedia that this works, but it does. Paul August 15:50, 7 October 2005 (UTC)
Butchering is silly talk (like it says below the box, If you do not want your writing to be edited mercilessly and redistributed at will, do not submit it). I cleaned it up to conform with our style. Freely-made comments about what I don't understand are also silly, as are threats to revert. Feel free to add back anything specific. I doubt you'll get much sympathy. Charles Matthews 07:06, 7 October 2005 (UTC)

I missed this thread first time around, but I noticed Charles Matthews say:

work in areas such as domain theory that do argue for replacements of set theory for purposes of theoretical computer science

This isn't quite right: domain theory (and especially synthetic domain theory) wants to build better mathematical structures for doing Tarski-style interpretations of programs into, but in turn the foundations of domain theory are regular set theory. It might be better to call it a better interface onto set theory than a rival to set theory. Martin-Loef's type theory is an example of an actual rival to set theory, which is, again, peddled mostly by theoretical computer scientists.

I agree with Charles M's objection though. The section of that article called "recent attacks" has as its most recent commentator Hermann Weyl! In the mathematicians section, Kline is not objecting to set theory as a mathematical structure, but to its role in mathematical education, in particular the air of unreality refers to the lack of good intuition a certain kind of emphasis on farmalism and foundations can lack (caveat: I don't recognise this particular passage of Kline, but I've read a lot of Kline and I know his hobby horses).

Having said that, I think that if we find the right home for this, there might be a nice article that can be grown for it. I don't like "criticisms", I'll make a proposal for alternative name candidates at Talk:Controversy over Cantor's Theory --- Charles Stewart 15:24, 13 October 2005 (UTC)

Khayyam-Pascal's triangle

Paskal's triangle has been moved to Khayyam-Pascal's triangle. It is claimed there now that the latter is the internationally recognized name. Discussion is welcome at Talk:Khayyam-Pascal's triangle. Oleg Alexandrov 21:35, 5 October 2005 (UTC)

Oh, just move back. We use the common name. The history can be dealt with in the article. This is the standard way. Charles Matthews 21:38, 5 October 2005 (UTC)
Your wish is my command, so I moved it back. -- Jinn Niesen (talk) 23:16, 5 October 2005 (UTC)

Category:Article proofs

This category has some proofs, as subpages. It seems to be at odds with two widely held views, one that there should be no subpages (Christoffel symbols/Proofs is a subpage to Christoffel symbols), and that the proofs should not be on separate pages. Also, wonder I, why is this separate from Category:Proofs. I myself would suggest the proofs in there, together with the mother category, be deleted. Wonder what other opinions are. Oleg Alexandrov 00:16, 6 October 2005 (UTC)

Are you proposing that articles in Category:Proofs like Cantor's diagonal argument and Proof that e is irrational be deleted, or just the ones in Category:Article proofs? I would disagree with the first statement, while I have no strong opinion on the second statement. Furthermore, nobody reacted when it was asked whether these subpages are allowed at Wikipedia talk:Subpages#Special dispensation for mathematical proofs several months ago, so one could argue that the prohibition on subpages does not apply here. -- Jitse Niesen (talk) 22:00, 6 October 2005 (UTC)
No, I don't suggest deleting all the proofs on Wikipedia outright. Just the subpages in Category:Article proofs. Oleg Alexandrov (talk) 23:06, 6 October 2005 (UTC)
Making them into full, self-sufficient, articles called, for example, Proofs of the Bianchi identities, would seem to be less wasteful; but I agree they should not stay where and as they are. Septentrionalis 02:57, 7 October 2005 (UTC)
Subpages bad. Articles like a hypothetical Bianchi identities (proofs) stand or fall by their general interest (Fermat's Last Theorem (proof) would obviously be OK). I agree that the Category:Proofs should be for pages about proof and types of proof, not pages giving specific proofs. Perhaps a list of 'sample' proofs for the latter? Charles Matthews 07:02, 7 October 2005 (UTC)

How about putting back those proofs into the articles? --MarSch 15:01, 7 October 2005 (UTC)

I don't want to lose these proofs, I think they are valuable. I don't see the problem in having them on a subpage. Can someone explain the harm in that? If we don't want them there, or in the article, or in a seperate article of their own, then we could always put them on the talk page, but I would be strongly opposed to just deleting that content. Paul August 15:20, 7 October 2005 (UTC)

Putting the proofs back into articles is out of question. Proofs are typically technical, do not add much to understanding the concepts in the article, and interrrupt the flow of the article. Let us not forget that we are dealing with encyclopedic essays here, oriented towards the general public.
Keeping them as subpages is not good either. There is no hierarchy on Wikipedia; each article should be able to stand on its own. I would argue that the only option beside deleting the proofs is keeping them on their own standalone page.
Now, are proofs that much worth it, besides some classical proofs? Proof articles will be visited more seldom than others, and will be harder to fact check, which raises the spectrum of some obscure articles with more errors than others. Oleg Alexandrov (talk) 18:09, 7 October 2005 (UTC)
I suggest deferring a decision for at least several years. WP has the potential of being more than just encyclopaedic, although this potential is years away. Math books are quite useful in that they provide (non-notable) proofs for their theorems. Although WP is still far away from being detailed at a level equal to that of a book, I think it would be a mistake to declare as policy that WP must ever become as detailed as a book. As to obscure articles with errors, I don't think the way to eliminate errors is to eliminate obscure articles. linas 00:52, 14 October 2005 (UTC)
Note that Proof of angular momentum is an excellent example: its crudy, haphazard and weak, yet has had a half-dozen editors and is translated into four languages!! People seem to like this stuff, and I don't think it should be banned on principle.
Also, some articles cite too many references (in my opinion), and I would like to see, in such cases, that the references (and footnotes) are banished to a subpage.
Think of "proofs" as something that is less formal than a real article, but more formal than a talk page. linas 01:02, 14 October 2005 (UTC)

The {style} template

The {{style}} template pops up every now and then at Wikipedia:Manual of Style (mathematics) and is there now. I would argue that it is unnecessary. Its only purpose is for a user to hop from manual of style to manual of style, but for people who actually use a particular manual of style, like our math manual, the links to the manual of style about writing China-related articles, how to write footnotes, etc, are not be helpful. I would argue that a link to the Wikipedia:Manual of Style on top of our manual of style should be enough. From there, one can access any other style manual if one wishes so. Wonder what people think. Oleg Alexandrov (talk) 04:12, 7 October 2005 (UTC)

Harmless; and if we remove it, it will be back. Why bother? Septentrionalis 20:03, 7 October 2005 (UTC) (And it makes the page look a little more "official", which can hardly hurt.)

Wikipedia: Make technical articles accessible

I posted a note on this guideline's talk page proposing a change in this policy (Wikipedia talk:Make technical articles accessible). --- Charles Stewart 02:22, 8 October 2005 (UTC)

Please vote on list of lists, a featured list candidate

Please vote at Wikipedia:Featured list candidates/List of lists of mathematical topics. Otherwise, the issue may be decided by (from the looks of it at this time) people who never heard of mathematics until they saw this nomination. Michael Hardy 03:35, 13 October 2005 (UTC)

Wikitextbooks or

I am attending an AMS sectional conference this weekend, and once again listening to everyone complain about how badly math is taught in the US, how lousy all the grade school textbooks are (except the Singapore textbooks), and how the three big textbook publishers are so powerful that nobody has a ghost of a chance of making things better.

Naturally, I thought of Wiki.

What I propose is a series of articles on mathematics written at the grade school level, so students and teachers who actually care about mathematics can have at least one source to which to turn.

I'm going to start at Grade school mathematics and take it from there.

Want to help?

Rick Norwood 22:46, 15 October 2005 (UTC)

I would like to help, but think a problem needs to be addressed first: stability. A book written by committee, and constantly changing, will be as bad as what's out there now. We would need to have one committed person in charge, who could review potential contributions from many authors and decide which to include as is, which to include with changes, and which to reject. This is rather "anti-wiki" so may not work here. That said, I suppose we could write many articles within the current structure with the goal of copying them and making them uniform, outside the wiki structure, to make a textbook, at some future date. StuRat 23:24, 15 October 2005 (UTC)
Agree w/StuRat on this point. I'm finding that WP articles tend to be "average" and not "excellent" because the excellent material in WP tends to get edited to oblivion. For a reference, such as WP, that's fine. For a textbook, which you learn from, "average" is not good enough. A better model is the Linux kernel, where an authoritarian few act as gatekeepers to contributions. linas 19:12, 16 October 2005 (UTC)
The first task, I would think, would be to come up with an ordered list of topics to be covered, by age group. A grade school book should have lots of colorful illustrations, so having a graphic artist on the staff would sure be a good idea. StuRat 23:31, 15 October 2005 (UTC)
Also, you should set up a project page for this, so discussion can take place there. StuRat 23:32, 15 October 2005 (UTC)
We have Wikibooks, with a few mathematics texts there already. See . Educational material should go there and not in Wikipedia. Dysprosia 00:44, 16 October 2005 (UTC)
Agree with Dysprosia. Wikipedia is for reference, it is a collection of encyclopedic essays. I am getting weary of people trying to use Wikipedia to fix the wrongs of the world. Oleg Alexandrov (talk) 03:53, 17 October 2005 (UTC)
Yes, please support wikibooks. Charles Matthews 09:23, 17 October 2005 (UTC)

Reminder: Wikipedia:WikiProject Physics !

Just in case there are still Quantum and GR types lurking here, who haven't yet found Wikipedia:WikiProject Physics ... well, now you know: there's a physics project as well. Add your name to the list, and visit the talk page as well: I'm sure the topics are as lively and maybe more argumentative than those here! linas 00:28, 18 October 2005 (UTC)

Mathematical characters usage

As most readers here know, Dmharvey is working on a MathML solution for Wikipedia, called Blahtex. A perennial problem in mathematics is the large number of potential characters, and the MathML spec defines quite a large list. For your viewing pleasure, I have made a page where you can try to see many of them in your browser. (The list does not include all the fraktur, script, and blackboard-bold characters, some of which are in a higher Unicode plane.) Using a Gecko-based browser (from the Mozilla Foundation) and the Code2000 font, I see excellent coverage. That's a Good Thing, because the STIX fonts have had their projected release pushed back to mid-2006. In light of evolving developments, the question here is, what do we do now in editing articles?

Because Wikipedia has switched to UTF-8, it directly accepts any Unicode character. We can also use HTML named entities, and character entities. Come MathML, readers must be prepared to cope with these. Meanwhile, the processing of <math> allows a limited subset, producing either an image or HTML markup. (The subset does not include the full set of LaTeX characters, much less the complete range of MathML characters.) Finally, outside of the <math> tags we can use images of characters.

Folks writing in other scripts, from Cyrillic to Devanāgarī to IPA to Hangul and others, seem unapologetic about the need for their kind of characters in their kind of article. With the advent of MathML presentation it will become extremely awkward and ugly to use the image crutch; we need our characters, too.

How many people are going to scream if I start writing the cross product properly as AB (using U+2a2f, &Cross;) instead of A×B (using U+00d7, &times;)? That's silly, right; who needs the fancy character? But I've also gotten curses for using the semidirect product, NH (using U+22c9, &ltimes;), which LaTeX calls "\ltimes" but <math> does not allow. (Especially annoying, the complainant thought a picture of &rtimes; was a fine substitute, even though it's the wrong character and precludes <math>!)

I will scream, because it shows up as a little square, like any other unreadable character. Please don't. Septentrionalis 18:40, 26 October 2005 (UTC)
Did you mean Cross or ltimes? Either way, one down, how many left to go? (By the way, your browser can read the character fine; it can't display it with your present setup.) Unfortunately, unless folks respond here an editor has no way to know which characters display for you as missing character boxes. I might be using FreeBSD and Firefox and Free UCS Outline Fonts, someone else might be using Mac OS X and Safari and default system fonts, and you might be using Win98SE and IE5 and Lucida Sans Unicode. Some kind of documented guidance could benefit everyone. That could be a list of safe characters, and/or suggestions for browser/font configurations to help in filling the boxes. --KSmrqT 20:40, 26 October 2005 (UTC)

So, are all characters fair game as numeric entities? As UTF-8? (Clearly not as <math>!) If not, which do we exclude, why do we exclude them, how do we substitute (in all contexts), and what do we do when MathML arrives? --KSmrqT 13:33, 18 October 2005 (UTC)

When using special characters, they should be properly displayed for, say, 90% of all readers. Thus at least IE should display them properly, and not just in one of its font settings. Otherwise it is better to use LateX, or if a symbol is not available, an image.--Patrick 13:28, 20 October 2005 (UTC)
Somewhat related was the discussion at Wikipedia talk:WikiProject Mathematics/Archive12#Unicode in math articles. There people objected against unicode but for different reasons.
With Firefox on Windows XP, I can't see one of the characters KSmirq wrote above, the one with U+2a2f, there is only a question mark in there. I guess it sounds reasonable that one not use the more exotic unicode characters, but rather TeX. Of course, TeX has the problem that the restricted Wikipedia dialect does not have all the symbols, but at least once the Wiki TeX parser agrees to generate a formula, it will be visible to everybody. Oleg Alexandrov (talk) 13:39, 20 October 2005 (UTC)
The archived discussion was about replacing numeric entities with UTF-8, which is related, but logically distinct. Using no UTF-8 beyond ASCII, an article can still use &2a2f; — which may not display as hoped. It is unrealistic to ask each editor to personally test special characters on all available OS/browser/font/config variations. Yet nowhere can I find any guide to what LaTeX constructions <math> tags support (including, but not limited to, characters); and nowhere can I find a guide to which characters are "safe" and which are not. Is my only resort trial and error, to try to use a character and see if the Wikipedia software or some other editor rejects it? Does that mean all mathematics must be written in ASCII?! That's an extreme example, but then where do we draw the line? Are all HTML 4.01 entities safe? Is any character in, say, Arial safe? Does Microsoft dictate through IE on WinXP? (If so, how are MacOS and BSD users to know what's safe?) And, again, MathML is looming (I hope!). --KSmrqT 16:04, 20 October 2005 (UTC)
I did not say you should use plain ASCII for math formulas. :) And, I think the issue is not with people using XP or BSD, rather, the browser might not have all the fonts installed.
I guess the rule of thumb should be that if you suspect a given Unicode character might cause problems, you better you TeX instead, if TeX supports that symbol. But ultimately math display on the web sucks no matter what you use. Oleg Alexandrov (talk) 00:54, 21 October 2005 (UTC)
FWIW, I now have three browsers at my disposal; IE 6, Netscape 7.2, and Opera 8.5. None of then see 2a2f, while all except IE see 22c9. Arthur Rubin (talk) 14:04, 23 October 2005 (UTC)
That sounds about right. Your report, however, omits needed details, since what you see depends on OS+fonts+browser+config. For example, try installing the Code2000 font and see what you get. In regards to suspecting a problem, why would anyone not using IE/Win think a character they can see might be troublesome? I'm sure we all agree that mathematicians are the brightest and best-looking people on the planet, but that does not equate to web or wiki expertise! :-D —KSmrqT 21:24, 23 October 2005 (UTC)
I'm running mac OS 10.4.2, with no additional fonts installed. On both Safari 2.0 and Firefox 1.0.6, I'm missing a large proportion of those characters. I haven't counted -- maybe missing 30% or so, especially towards the second half. Dmharvey File:User dmharvey sig.png Talk 00:03, 24 October 2005 (UTC)
That makes sense. Some of the MathML entities are composites, such as a relation overlayed by a negation (e.g., solidus), but otherwise I listed them in numeric order. The higher code blocks are likely to be more esoteric, and less well covered by standard fonts. Without the Code2000 font I get coverage like yours; it would therefore be interesting to know if adding that font completes your coverage. I hesitate to ask you to compare IE5/Mac [19]. --KSmrqT 02:56, 24 October 2005 (UTC)

An approach I've taken is to provide links to bitmap images for characters which don't display on every browser. That way, at a minimum, users can click on a link to see characters like  ∈,  ∉, ,  ⊆,  ⊂,  ⊇, and ⊃; if they don't display on that user's browser. StuRat 00:12, 1 November 2005 (UTC)

That is a nice service, but and can better be displayed as image directly, they give most problems.--Patrick 07:44, 1 November 2005 (UTC)
I'm guessing you mean the fewest problems ? StuRat 08:35, 1 November 2005 (UTC)
I mean, they are the symbols which give the most problems if they are not displayed as TeX image but coded with &notin; and &empty;.--Patrick 00:56, 3 November 2005 (UTC)
Sorry to take so long to respond; busy elsewhere. This is a creative idea, but hampered by two crippling drawbacks. The first is that seeing a formula with boxes on one page, and individual symbols separately, adds up to an unreadable formula. The second is unintentional creation of a mistaken symbol, which came up in a different context when the suggestion was made that a formula could link to explanations of its operators. This happens because many browsers are configured to underline links. Two examples:
  • "2+2=4"
  • "For all primes p>2, p is odd."
Obviously, "+" and ">" aren't special characters (so everyone can appreciate the examples, which look like "±" and "≥"); but the general danger should be clear. --KSmrqT 03:07, 3 November 2005 (UTC)
I agree that having the formula right there is better than having to follow links to read the missing symbols, but still think that's infinitely better than just having boxes with no links at all. The underline problem is a good pt, but I think they are usually blue underlines to distinguish them from regular black text, so that might help some. Another idea is to have a pic of the entire formula, not just each symbol in the formula. StuRat 05:15, 22 November 2005 (UTC)
As my preferences are configured, they show the underline. And mine are pretty default except that I added MathML when possible, which I don't think affects this issue. It's probably not a good idea to assume people won't see the underlines. --Trovatore 05:20, 22 November 2005 (UTC)
And are they blue underlines that can be distinguished from regular black text ? StuRat 05:24, 22 November 2005 (UTC)
The underlines are blue, but so are the characters. It is not obvious that they are not part of the symbol. --Trovatore 13:42, 22 November 2005 (UTC)

Semidirect product symbol

The common notation of a semidirect product seems to be G = N File:Rtimes2.png H, with the normal subgroup at the left, while the symbol is a cross with a vertical bar at the right (see e.g. [20]), although the names of the symbols seem to suggest that the bar should be at the side of the normal subgroup ([21], [22]). Have other people any thoughts?--Patrick 13:37, 20 October 2005 (UTC)

Perhaps it would be better to redirect such a specific discussion to Talk:Semidirect product? --KSmrqT 19:23, 20 October 2005 (UTC)

move of manifold/rewrite/*

The main article was moved, but the two subpages weren't. differentiable manifold, topological manifold redirect there. Admin privileges probably needed, since I couldn't do it. --MarSch 11:14, 20 October 2005 (UTC)

I will take care of this now. Oleg Alexandrov (talk) 11:20, 20 October 2005 (UTC)
Done. I also merged their edit history with the corresponding ancient redirects created by Toby Bartels in 2002 or so. Oleg Alexandrov (talk) 11:27, 20 October 2005 (UTC)
Thanks --MarSch 11:37, 20 October 2005 (UTC)

Live preview

This is not about math, but might be helpful to the fellow mathematician. I found a very userful tool in my opinion, Pilaf's Live Preview at Wikipedia:Tools#Alternative_previews. It allows one to do instant preview, without waiting for seconds or more after hitting the "Preview" buttion. It works by some javascript magic, and is just as easy to install as pasting several lines of text into a file and doing a reload of your preferences (control-shift-r for Mozilla, Ctrl-F5 in IE, and F5 in Opera). I already love this tool. :) Oleg Alexandrov (talk) 12:51, 25 October 2005 (UTC)

Note that it does not do LaTeX formulas, and does not show redlinks as red (one needs to check with the server for things like that), so the good old preview is still needed, but it can still cut the number of times one needs to use the usual Preview button. Oleg Alexandrov (talk) 14:02, 25 October 2005 (UTC)


Hey! In a case of absent mindedness, you forgot to classify the numbers. I searched a lot. If already present, I apologize. --Davy Jones 02:50, 26 October 2005 (UTC)

who's you and what numbers are you talking about? --MarSch 09:29, 26 October 2005 (UTC)
Firstly, I am persuing my bachelors degree in engineering. secondly, I mean the classification of numbers into Real numbers and Imaginary Numbers and their subdivisions. this willl clear the basics of numbers for the novice. --Electron Kid 00:14, 27 October 2005 (UTC)
Still don't understand what it means to classify a number. linas 00:24, 27 October 2005 (UTC)

Please note the plural numbers. Its like : numbers have been classified as Real numbers and complex numbers. complex numbers are further classified as complex and imaginary. Real numbers are further classified as rational and irrational. Rational numbers = fractions + integers. Integers = (negative numbers) + (Whole numbers). Whole numbers = 0 + (natural numbers). Further, a different symbol is used to represent each set. I thought of adding a page, if not already present. --Electron Kid 01:00, 27 October 2005 (UTC)

I really wouldn't recommend adding such a page. I would guess it would show up on AfD very quickly. You might take a look at the number article and seeing if you want to add a section there; it mentions various sorts of numbers, but not in that sort of hierarchy.
By the way, 0 is a natural number for lots of mathematicians, including me; the locution "whole numbers" is almost never used except in high school math texts, or perhaps in some informal contexts. --Trovatore 01:10, 27 October 2005 (UTC)
I find the discussion at number page to explain very well what kinds of numbers are out there. Oleg Alexandrov (talk) 02:55, 27 October 2005 (UTC)
Yeah, number already covers all of this. (Anyway, electron kid, I don't think your classification of "numbers" into "real" and "complex" does much justice to all the other wonderfully wacky kinds of "numbers" that mathematicians have thought up... p-adic numbers, ordinal numbers, etc etc) Dmharvey File:User dmharvey sig.png Talk 03:23, 27 October 2005 (UTC)

Differentiating Functions on AfD

The article Differentiating Functions is on AfD (doesn't show up in the Current Activity page because it's not in any math category). The article is very badly written, though one editor seems to think it's more accessible than Calculus with polynomials, which I find hard to credit.--Trovatore 05:52, 28 October 2005 (UTC)

What's the current activity page? -Lethe | Talk 06:15, 28 October 2005 (UTC)
Wikipedia:WikiProject Mathematics/Current activity --Trovatore 06:23, 28 October 2005 (UTC)

Boolean algebra

Without some support on Boolean algebra, I think I may just merge it into Boolean logic, take the flak and pick up the pieces later. It is clear that making it a purist page meets continuing resistance. I don't do edit wars. Charles Matthews 21:40, 28 October 2005 (UTC)

Look, I don't care what the articles are called, within reason. But there needs to be a page on the algebraic structure. I've already expressed a willingness to have it called Boolean algebra (algebraic structure), with Boolean algebra itself containing the content now in Boolean logic. I see no reason that latter page (whatever it's called) should even refer to the algebraic structure, except maybe a line or two about related topics.
It occurs to me that the page on the algebraic structure might be made more accessible with a picture of the eight-element BA (its Hasse diagram, say, with the bottom node black, the next three red,green,blue, the next three yellow,magenta,cyan, the top one white, and explanation of how the \land and \lor correspond to following lines on the graph). Anything to make it clear that we're interested in the structure itself, not just the corresponding logic. I'm not very good with making such pictures--anyone want to draw it up? --Trovatore 22:07, 28 October 2005 (UTC)
I agree with Trovatore on this one. Merging the two articles won't help, but will lead to continuous edit wars between you guys and the general public, both of whom want different things from the article. StuRat 22:50, 28 October 2005 (UTC)
Looking at both Boolean algebra and Boolean logic, neither one clearly says "theory" or "application" — not in so many words, and not in the content. In my experience, that's usually a false dichotomy; but if that's what's intended, say so emphatically. Meanwhile, I've rewritten the opening of Boolean algebra (which had lapsed into nonsense), and said a few words on its talk page. Hope it helps; and good luck. --KSmrqT 03:03, 29 October 2005 (UTC)
No, that's absolutely not the intended distinction (at least, not my intended distinction; certainly other contributors may have different opinions). The distinction I have in mind is between the algebraic structure (currently at Boolean algebra), and the propositions that are true in those structures (currently at Boolean logic). So for example "How many elements has the Boolean algebra B?" is a perfectly sensible question, whereas "How many elements has Boolean algebra (i.e. Boolean logic)?" is complete nonsense. --Trovatore 03:12, 29 October 2005 (UTC)
The difference in emphasis isn't strictly application vs. theory, although the Boolean logic article certainly has more application text and the Boolean algebra article has more theory. The Boolean logic article could be described as "the theory and application of the common subsets of Boolean algebra which apply to real-world applications". StuRat 03:18, 29 October 2005 (UTC)

I've done a little research on this, and the split over the articles is typical of mathematical encyclopedias (the Soviet one has algebra of logic + Boolean algebra, the Japanese some sections on symbolic logic + Boolean algebra). So it is not actually eccentric to divide it the way it currently is. That being said, I've heard nothing that convinces me there are two separate subjects, any more than discrete mathematics is disjoint from logic or computing applications. Charles Matthews 06:39, 29 October 2005 (UTC)

I think there is nothing at Boolean logic which shouldn't be at Boolean algebra and I dislike extremely how half of the article is doing set theory. Please go ahead and merge them Charles. --MarSch 12:42, 1 November 2005 (UTC)
As I said before...Merging the two articles won't help, but will lead to continuous edit wars between you guys and the general public, both of whom want different things from the article. StuRat 19:14, 1 November 2005 (UTC)
I feel quite bad with Boolean related articles. It appears that the special case of algebraic structures with 2 elements makes everything unclear: you may define a boolean ring, a boolean algebra (which should assume scalar multiplication, even with scalar in {0,1}), post algebra (there you use (i.e. XOR, i.e. + modulo 2) instead of thus building a field), boolean logic axioms, order on 0 and 1, aso. From there you can extend to boolean polynomial algebra, boolean logic, boolean lattices, and if you choose + mod 2, you can go to vector fields and end into algebraic graph theory. All of these things are, in my personal opinion, different as the "main" property which is used in an algebraic structure are niether the particular elements or operations which are used, but the axiomatic which is assumed; even if the elements and the operations are the same, the mathematical context is given by the axiomatic, which will usually allow more general reasonning. pom 18:27, 26 November 2005 (UTC)

Nov 2005 – Dec 2005

Wikibook proposal

Since the purpose of the article originally started by StuRat was in part didactic, how about farming it out as a wikibook? There is still the historical question of the relation of Boole's algebra to the different entity called Boolean algebra to be sorted out, and yet another new article housed at BL might be the best place to do this. The new article can then comment on the non-mathematical aspects of cultural usage that originalyy prompted StuRat to write his text, and the genuinely encyclopediac contribution of the BL article can still be accomodated in the BA article. --- Charles Stewart 18:57, 1 November 2005 (UTC)

I have no objection to there being a WikiBook on either, or both, the current Boolean logic content and the current Boolean algebra content. However, if this is to be used as a justification for deleting either article, in whole or in part, from WikiPedia, I am strongly opposed to that. StuRat 19:07, 1 November 2005 (UTC)
The new article would not be based on your article, but it would be non-PhD-level and it would document what non-algebraists get out of the mathematics. I don't think that a compelling case for en.wikipedia to host an introduction to BAs for people who don't want to learn algebra has ever been made, if that is the deletion that my proposal makes that you object to. --- Charles Stewart 19:11, 1 November 2005 (UTC)
The basics of set theory are taught well before algebra in school. For example, an episode of the PBS kids (ages 7-11) math show Cyberchase contained an introduction to set theory including Venn diagrams. Any assumption that elementary set theory, and the Boolean logic operations based on it, requires advanced algebra, is therefore faulty. StuRat 19:40, 1 November 2005 (UTC)
I don't see the relevance of your remark to mine. --- Charles Stewart 20:17, 1 November 2005 (UTC)
I was responding to the statement "I don't think that a compelling case for en.wikipedia to host an introduction to BAs for people who don't want to learn algebra has ever been made...", which seems to be saying that a knowledge of algebra should be required to understand the introduction sections. My point is that the introductory level material can be made without the use of algebra, and that such material can be added later. StuRat 20:55, 1 November 2005 (UTC)
I made no such claim. WP articles on topics of broad interest should be accessible, even if the article should contain material that is not generally accessible. Wikibooks is the place for tutorials, see WP:NOT, point 8 of Wikipedia is not an indiscriminate collection of information, which is what "an introduction to BAs for people who don't want to learn algebra" would be. What is at stake in hosting such an introduction here rather than there? I see no point of principle at play here besides the one about following policy. --- Charles Stewart 15:38, 2 November 2005 (UTC)
Your statement that "WP articles on topics of broad interest should be accessible..." seems to imply that you don't think that we should have the goal of making all articles accessible. I disagree, and think that all articles should be made accessible to the broadest audience possible. Removing info from Wikipedia makes it considerable less likely to be found and thus less accessible. StuRat 15:56, 2 November 2005 (UTC)
I believe that there are articles for which it is not very important to spend much time thinking about the general reader, but instead most effort should be directed at the specialist. As you are aware, I've been citing analytic continuation as an example of this for some time. --- Charles Stewart 19:12, 2 November 2005 (UTC)

I don't think suggesting a wikibook is helpful. What is in wikibooks and what is here is in no way related.--MarSch 18:31, 2 November 2005 (UTC)

Are you disputing the policy? Are you aware that both WP and Wikibooks are both hosted by and reflect the values of the Wikimedia Foundation? --- Charles Stewart 19:12, 2 November 2005 (UTC)
I believe MarSch means the same thing as me, that while adding a WikiBook on any topic is a worthy goal, to use that as a justification for deleting material from WikiPedia, if that is your intent, is not at all helpful. StuRat 20:00, 2 November 2005 (UTC)

Issues with the real numbers

See Talk:Mathematical analysis#Mathematical.2FReal Analysis. A fellow is having problems with the modern defintion of real numbers (among other things). He/she says "infinitesimals exist". My reply would be that the real numbers are defined by axioms, and it follows from those axioms that there are no infinitesimals. It would be good however to have more in-depth comments than that on that talk page. Oleg Alexandrov (talk) 11:22, 29 October 2005 (UTC)

I would take the reals to be defined in terms of other things rather than axiomatized, but the answer comes out the same: "this is what we're talking about; talk about whatever you like, but don't call it the reals". At a cursory glance it looks like you're arguing with a crank over there. The best way to do that is not to; since he seems to have given up, I'd just let it go. --Trovatore 19:49, 1 November 2005 (UTC)
Infinitessimals exist, John Conway does a marvelous and fun construction in "On Numbers and Games". Although they exist in between real numbers, they're not exactly "numbers" themselves, though. I've always wondered if its possible to do some sort of calculus with them, e.g. treat them as some sort of fiber bundle or something over the reals, and get something other than trivial results. No idea. linas 16:04, 3 November 2005 (UTC)
WHat about non-standard analysis? --MarSch 16:57, 3 November 2005 (UTC)
and Non-standard calculus? --MarSch 17:06, 3 November 2005 (UTC)
J.H. Conway's surreals and NSA's hyperreals are both interesting structures (or classes of structures in the case of the hyperreals; there are nonisomorphic structures that fit the description). But they aren't the reals. Considerations involving them may tell us things about the reals, but they aren't the reals. Sorry to use baby talk; I imagine that both of you know these things--I'm just listing the points that can't be fudged when presenting the material to naive readers, or when having a discussion with a crank (if the latter is adjudged necessary). --Trovatore 17:10, 3 November 2005 (UTC)
The infinitesimals are not real, and they are not imaginary either. Gosh, what's left then? Oleg Alexandrov (talk) 17:45, 3 November 2005 (UTC)
My professor in introductory calculus would occasionally refer to indeterminate forms, infinities, and infinitesimals as "Christmas trees". Actually quite a good way to stop you from carelessly using them as regular numbers. Fredrik | talk 18:01, 3 November 2005 (UTC)
It's worth amplifying on non-standard analysis, though I think the original discussion was at a much lower level of sophistication. Suppose we lay out a system of axioms for the reals, then look around for possible models that satisfy those axioms. A standard model includes just what we expect and no more. A non-standard model — which supports the same set of theorems — can exist and have extra goodies like infinities and infinitesimals. To put the extra goodies to work requires careful distinctions. Another tactic is to use topos theory and the different logics that allows. In this way we get a somewhat different version of infinitesimals such as those discussed in smooth infinitesimal analysis [23] (PDF). A limited number of mathematicians enjoy these foundational games; many more seem to take the attitude "go away, we're trying to get work done here". But then, I remember hearing some insist that category theory was a waste of time, on the one hand; and I've seen topos logic [24] (PDF) [25] [26] put to serious work in the semantics of programming languages, on the other hand. I feel it's a delicate topic, because while I'm in the camp that enjoys foundational explorations, I'm painfully aware that most of the people who raise questions on Wikipedia about infinities and infinitesimals are clueless cranks. Too often the cranks are able to get some leverage because of loose writing, acceptable for informal mathematical discussion but not careful enough to stave off false interpretations. It's a difficult discipline, should one choose to accept it. For thousands of years mathematics progressed with stronger intuition than foundation, and I suspect that even though we're taught we should respect foundations today, many still just pay lip service. And for good reason: if we have to dot every "i" and cross every "t" any time we speak, we'll be tongue-tied. --KSmrqT 20:31, 3 November 2005 (UTC)


During the travails of my spellbot, I got the following comment:

It turns out that both "parameterize" and "parametrize" (the bot's spelling) are very common; M-W lists both. I learned the first version somewhere back in the mists of time and only found out just now of this variant. I was actually surprised to see that in many of my books also use the second version, and I never noticed... (incidentally the bot also corrected a "parameterise" to "parametrise", too. Yay for bots that also know British spelling :-) Choni 13:06, 29 October 2005 (UTC)

Makes me really wonder, is it indeed correct/widespread to use "parameterize" (one extra "e") as synonymous with "parametrize"? I never encountered the former, even though it would make sense as it all comes from "parameter". Thanks. Oleg Alexandrov (talk) 13:15, 29 October 2005 (UTC)

I am only familiar with the former version. It seems more natural, being closer to the root word, as well. StuRat 23:55, 31 October 2005 (UTC)
American Heritage seems happy with both, nodding slightly towards including the "e". That agrees with my practice when writing or proofreading: either is fine. It might be nice if an article was at least self-consistent, but frankly I doubt many readers would notice. In contrast, "parametric" does not allow an extra "e". --KSmrqT 00:11, 1 November 2005 (UTC)
Of the four permutations, the only one that looks really wrong to me is "parametrise". I think british and american speakers actually pronounce the word slightly differently. (I'm an Australian speaker.) Reminds me of aluminium vs aluminum. Dmharvey File:User dmharvey sig.png Talk 00:14, 1 November 2005 (UTC)
I think aluminium is what is used in most languages. Therefore I prefer to use it also in English. --MarSch 12:45, 1 November 2005 (UTC)
The situation is a bit different, because in the case of Aluminium, there is actually an international standard that specifies the official name as "Aluminium", and not "Aluminum". See for example IUPAC Periodic Table of the Elements, which says: '“Aluminum” and “cesium” are commonly used alternative spellings for “aluminium” and “caesium.”'. As an American, I find this annoying, but that's the way it goes. -- Dominus 15:49, 1 November 2005 (UTC)
Hey that's good :) Now we only need to get rid of potassium and call it Kalium instead.--MarSch 17:07, 1 November 2005 (UTC)
Sure, but then we need to find a way to extract it from kale, instead of potash. 17:58, 1 November 2005 (UTC)
Americans don't get annoyed; we effect regime change. I can say that now that I'm in Canada. Then again the Canadians might not know I'm joking. --Trovatore 20:28, 1 November 2005 (UTC)
Yea, you might get kicked "oot". StuRat 20:46, 1 November 2005 (UTC)
Let's get back on task, eh? For what it's worth, I've met people (including myself) who insist it should be spelled "parametrize" (or "parametrise" if you live across the pond). I'm not sure how often I've run into the latter, though. - Gauge 03:45, 10 November 2005 (UTC)

Hilbert problems

The Hilbert problems page is seeing some development, which is only right and proper. It is also raising numerous issues, in respect of what a 'solved' problem is. This is an opportunity, to do better than other Web treatments (few of the historians really have all the background to write with authority on all 23). The words 'worms', 'can' and 'of' come to mind.

I wonder whether the laudable effort to get a table summary of it all on the page hasn't had its day. It is hard to write enough in a table entry, since some of the problems have several 'ply' in them. I also think that where [[Hilbert's n-th problem]] is now a redirect, we really need to have the buffer of a separate page. For example, Hilbert's fifth problem used to redirect to Lie group, but it seems clearer not to have arguments about what a Lie group is, and what the Fifth Problem was, on the same page.

Please come and help. This page missed Featured Article status over the summer, but has already been much expanded. Charles Matthews 09:49, 3 November 2005 (UTC)

Help wanted at rotation

See talk:rotation#Request for comment. Oleg Alexandrov (talk) 00:58, 6 November 2005 (UTC)

proofs of quadratic reciprocity

If anyone's feeling energetic, I started an article on Proofs of quadratic reciprocity. Sadly, it was a bigger job than I foresaw, and I've had enough for now. It needs several things done to it; see Talk:Proofs of quadratic reciprocity for my opinion on this. Thanks! I should go back to writing blahtex and existing in the real world now... Dmharvey File:User dmharvey sig.png Talk 03:11, 6 November 2005 (UTC)

I've intervened to link to Gaussian period to use indirection on the quadratic field. IMO this can be an interesting page, but mainly to send the reader to other parts of the site. Charles Matthews 11:17, 6 November 2005 (UTC)


Wikipedia:Categories for deletion/Log/2005 October 30 - the classification of academics needs a big clean-up. Please come and vote. Charles Matthews 11:56, 6 November 2005 (UTC)

Articles listed at AFD

Unfortunately, the automation makes it difficult to manually add articles such as this to the current activity list. Uncle G 00:53, 10 November 2005 (UTC)

    • Done (by placing {{math-stub}} in the article). It should be picked up, eventually. Arthur Rubin (talk) 01:14, 10 November 2005 (UTC)

Exclusive nor

See the talk page. Has anyone else heard of this, outside of MathWorld? Arthur Rubin (talk) 01:14, 10 November 2005 (UTC)

It would seem more logical to me to call this thing NXOR, per the suggestion at the talk page. XOR is probably a more familiar operation than NOR, and it is much easier to figure out what NXOR means: XOR goes 1 only on different inputs, so NXOR must go 1 only on the equal inputs. With XNOR one would probably have to draw a truth table. I checked that it is also equivalent to XAND, but people probably aren't used to working with XAND (I wasn't until I thought about it a bit). - Gauge 04:23, 10 November 2005 (UTC)
If it is true only on the same inputs (both true or both false), wouldn't the simplest and most logical name be SAME ? StuRat 11:46, 10 November 2005 (UTC)
I don't think we should use the name that seems simplest, but rather the name accepted in the mathematical community. Anyway, my TI calculator says XNOR, not NXOR. -Lethe | Talk 14:31, 10 November 2005 (UTC)
There are also far more Google hits for "logical SAME" than either "logical XNOR" or "logical NXOR", see the article's talk page for details. I would say that this is evidence it is more accepted by the mathematical community. Note that while "SAME" is a normal English phrase, "logical SAME" is not. StuRat 14:39, 10 November 2005 (UTC)
Many of the google hits for "logical SAME" seem to be consecutive sentences the first of which ends in logical, while the second starts with same. some seem to be grammatical errors for "logically same". I see very few google hits for "logical SAME" which indicate that it is used as an operator in logic or CS. I think your hit count is unreasonably high, given that you're searching two very common english words. On the other hand, when you google xnor, every single hit is about the logical/CS operator. Could you perhaps provide a textbook (or something more authoritative than google) that uses SAME for this operator, because I'm of the opinion that it's always called XNOR. -Lethe | Talk 16:09, 10 November 2005 (UTC)
I will look for some. Meanwhile, can we keep the discussion on the article's talk page ? Having it in two places seems quite unnecessary. StuRat 17:01, 10 November 2005 (UTC)
I have a design that comprises 18 such gates open in another window as I write this. xnor is what such a gate is called in Verilog. Uncle G 15:03, 10 November 2005 (UTC)

Function Iteration -- possible OR

The new article Function Iteration has the general smell of being original research. It doesn't look wrong, it just looks home-grown. Anyone care to do something about that? AfD maybe? linas 01:26, 11 November 2005 (UTC)

AfD seems like a good idea. Fredrik | talk 01:32, 11 November 2005 (UTC)
I would agree with that. Oleg Alexandrov (talk) 02:00, 11 November 2005 (UTC)
Seems borderline to me. I think the math project has quite a lot of stuff that people figure out themselves by routine methods, on the theory that it must be written up somewhere, and I think it would be counterproductive to get too rigid about OR when it comes to that sort of thing. But yes, this is probably over the line; it's a bad sign that the author signed his work. Maybe just redirect to Attractor? --Trovatore 02:49, 11 November 2005 (UTC)
Isn't there some template that would say something like "this may be OR/POV, but nobody is quite sure, it can be true, citations are needed"? It would be more apropriate than deletion in some cases. It's the second instance of this I came across lately. Samohyl Jan 07:28, 11 November 2005 (UTC)
Needs citations to show it's already published. Otherwise to AfD as original research. Charles Matthews 08:44, 11 November 2005 (UTC)
The last section of Function iteration names Paul Bird as its author. A previous version of the article Scalar Gravity also mentioned named. Scalar Gravity is probably original research; see the discussion on Wikipedia:Articles for deletion/Scalar Gravity. That enough evidence for me to suspend my assumption of good faith, so I replaced the whole article with a redirect to function composition. In fact, since time immemorial (diff) the latter article includes the sentence
"In some cases, an expression for f in g(x) = f r(x) can be derived from the rule for g given non-integer values of r. This is called fractional iteration."
It is a pity though as it is an interesting subject, but original research has no place in Wikipedia. -- Jitse Niesen (talk) 13:23, 11 November 2005 (UTC)

more on "article too technical"

see Wikipedia:Village pump (policy)/Archive Q#Frustration with make technical articles accessible policy

Dmharvey File:User dmharvey sig.png Talk 18:55, 11 November 2005 (UTC)

a list or a category of categories

I want there to be either a list of categories or a category of categories here. The more I think about it, the more I think it should be a list, not a category. One reason is that some categories probably don't deserve their own articles. Another is that it might be neat if we could put the categories in a table and like list their properties (cartesian closed, concrete, abelian, monoidal, etc). But then again, I've never liked (wp organizational) categories. Anyway, I started a list, which is basically just me adding a whole bunch of categories to the short list that was already at category (mathematics), in my user space because I wasn't sure if it should be an article. Have a look? -Lethe | Talk 06:10, 12 November 2005 (UTC)

You mean like the category of small categories? (couldn't resist...) - Gauge 05:39, 13 November 2005 (UTC)
Having a list of categories (as in category theory) would be nice. However, I find the table at the link you mention intimidating. I have no idea of categories, that is just an esthetic observation; maybe the table is useful. Anyway, if you decide to make such a list, it is good to add it to the List of lists of mathematical topics and also categorize it in Category:Mathematical lists. Oleg Alexandrov (talk) 17:23, 12 November 2005 (UTC)
If a programming metaphor will help, think of categories as an object-oriented approach to mathematics. (Hidden humor intended.) The idea is to approach structures through maps. For example, look not just at vector spaces, but also at linear transformations, the maps that preserve the structure. Look not just at groups, but also at group homomorphisms. In fact, category theory has found that the structures themselves (called objects) are less important that the maps (called arrows). We can give an arrow definition of "product", say, that applies identically to any kind of category. (Example: an individual poset is automatically a category, with an arrow AB meaning AB; its products are greatest lower bounds.) By the same reasoning, we study category-to-category maps (called functors), such as the forgetful functor that maps a vector space to the additive group of its vectors. We also consider functor-to-functor maps (natural transformations). By adding additional axioms we isolate categories (called topoi) that can replace sets as a foundation for all of mathematics. A table of categories (hint: good name) has the potential to organize diverse topics in a way that reveals common patterns. Category thinking has already had a broad and subtle influence on mathematics. (Warning: POV ahead!) In much the same way as lesser beings see groups and vector spaces everywhere, higher beings see categories. ;-) --KSmrqT 13:31, 13 November 2005 (UTC)
I think both a list and a category are appropriate. However the category name needs some thought, because it seems unavoidable that it will use the word "category" in two quite distinct senses in one short phrase. For example Category:Mathematical categories isn't good, because it looks like it should be a collection of all subcats of Category:Mathematics. The only things I can think of that are clear sound a little like jokes (e.g. Category:Category-theoretic categories. Actually maybe that one's not bad; once you get over the sound of it, it pretty much covers what needs to be covered. --Trovatore 17:29, 12 November 2005 (UTC)
As regards the list, please note that there is already a List of category theory topics, and it includes a section that has some of the function of Lethe's new list. The lists should be coordinated in some way: The new list could be merged into the old one; the now-redundant part of the old one could be removed, with a link to the new one; or minimally, there could just be dab-style notices at the top of both. The name List of categories suffers from the same linguistic problem mentioned in my last intervention. Could be List of category-theoretic categories. --Trovatore 17:47, 12 November 2005 (UTC)
I took your suggestion on the name of a category. I went ahead and created the category. I probably will move the list into article space at some point as well. -Lethe | Talk 18:21, 13 November 2005 (UTC)
Cool. I've made it a subcat of Category:Category theory, and removed that now-redundant category from the articles in both. --Trovatore 19:17, 13 November 2005 (UTC)
What's a pipe category? -Lethe | Talk 00:34, 14