Wikipedia talk:WikiProject Mathematics/Archive 47

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Archive 40 Archive 45 Archive 46 Archive 47 Archive 48 Archive 49 Archive 50


An initiative has just been launched to try to breathe more life and kudos into A-Class and A-Class review activities. Project members are warmly invited to participate. See: Wikipedia:WikiProject Council/Coordinators' working group. Geometry guy 19:32, 23 February 2009 (UTC)

Wikiproject Council? This is news to me. As I suspected, they have now fallen to squabbling on the talk page.
Does "kudos" mean badges, awards, medals? I would think just working to improve math coverage would be a suitable reward for most of us. After all, it's not as if math editors get much praise anyway, usually we just get people demanding we explain things simply and not in the self-gratifying manner we usually explain things so we can feel good about having math degrees.
"more life" would be good, but as always, that's always an issue in everything. I don't see what more there is to do, and I think in terms of overall progress, we are doing better than most projects. Do you disagree? --C S (talk) 13:21, 28 February 2009 (UTC)

New contributor in numerical analysis

I noticed four or five new articles today from the same contributor on the topic of fast numerical algorithms, especially classical 18th century work. The content is reasonably high quality and contributed in both English and Russian, but the wiki style and wiki integration is poor. I tried to fix some things, but probably this could use some more help, especially from people who can link to these articles from our existing relevant articles or even just merge them into topically identical existing articles:

Added Complexity of computation (bit)
Added Fast algorithms
Added The AGM method of Gauss
Added The FEE method
Added The Karatsuba multiplication

If anyone is comfortable editing in Russian, I think some of the same issues are in the Russian versions. I suspect English is not the new contributor's native language, but the English in the articles is usually good. JackSchmidt (talk) 13:18, 26 February 2009 (UTC)

Four color theorem nominated for A-class review

This is an old A-class article, one that attained its rating before the system went into effect. The nomination is here. I went through and fixed what I thought were the biggest issues: lack of citations, some errors, and just cruft. More eyes would be helpful. --C S (talk) 10:44, 28 February 2009 (UTC)


There is a cfd for Category:Second wranglers currently going on here. Some informed views would be useful. Occuli (talk) 14:08, 1 March 2009 (UTC)

Does it seem strange to anyone else that User:Black Falcon participated in the prior discussion for Category: Senior Wranglers (influencing some later comments) and then closed it as a delete, based on apparently the strength of his/her own argument? After all, all of the delete arguments before his weren't clear either and based on the notion that this is like being a valedictorian from some college. Then his became an argument that the only good reason to keep was not sourced. --C S (talk) 23:52, 1 March 2009 (UTC)
It seems strange to me. There was the other far-fetched comparison with Eagle scouts, the last comment, made 2 weeks after the penultimate comment. I feel a drv coming on. Occuli (talk) 01:14, 2 March 2009 (UTC)
The relist, in which he changes the focus from miscapitalization to outright deletion, makes him effectively the nominator for the CfD, making it highly inappropriate for him to close. Additionally, as comments on the new CfD make clear, some participants who would have argued for keeping didn't take it seriously based on the fact that they thought it was only about capitalization and didn't find out about the later change of focus. DRV seems like a good idea. —David Eppstein (talk) 01:31, 2 March 2009 (UTC)
Since I closed the discussion, I think it would be appropriate for me to comment here. My thoughts on the matter are as follows:
  1. The discussion for Category:Senior Wranglers stopped being just a renaming discussion when the first user suggested deletion. Once a category is nominated at WP:CFD, the course of the discussion rather than the initial nomination determines what will be done with it.
  2. My participation in the discussion was limited to relisting the discussion and posting what was intended to be my closing rationale (I relisted it instead of closing it due to the fact that both categories were not tagged at the time), so as to hopefully stimulate additional discussion. It is a mistake to equate evaluating of the merits of the arguments with the actual making of an argument one way or the other.
  3. The discussion was open for more than one month, which is significantly more than the 5 days spent on most category discussions.
I do not object to having my close evaluated at deletion review and I am perfectly happy to see the outcome overturned if there is agreement that I failed to properly evaluate the consensus or that there was not sufficient opportunity (either due to time or confusion regarding the scope of the nomination) to properly discuss the category. –Black Falcon (Talk) 02:25, 2 March 2009 (UTC)

Weird edit!!

This is weird. This was an article about an Australian combinatorialist, who is not the same person as the American mathematical physicist at the University of Toledo, who was born in Connecticut. A couple of edits earlier, someone added the "University of Toledo" category, although the Australian mathematician was never affiliated with that institution. Then this edit changed the article to be about a different person. Michael Hardy (talk) 16:34, 3 March 2009 (UTC)

PS: The AfD discussion was about the Australian. Michael Hardy (talk) 16:34, 3 March 2009 (UTC)
Perhaps we should create two new articles: Geoffrey Martin (Australian mathematician)

and Geoffrey Martin (American mathematician). Charvest (talk) 18:20, 3 March 2009 (UTC)

The American one (ie the present one) could be moved to Geoffrey K. Martin (supported by genealogy.math) and the Australian one restored. Occuli (talk) 20:27, 3 March 2009 (UTC)
That sounds like a good solution to me. I'll see if I can do that in a way that splits the history properly. It will likely involve some temporary deletion of the article. —David Eppstein (talk) 21:07, 3 March 2009 (UTC)
Having searched Google, I now reckon both articles should be deleted. Charvest (talk) 21:45, 3 March 2009 (UTC)

But the deletion discussions should be separate. Michael Hardy (talk) 21:48, 3 March 2009 (UTC)

I've started a deletion discussion on the Australian one (I'd have used prod but for the previous afd). I'm less certain that the other one should go, though, so someone else can start that. —David Eppstein (talk) 22:14, 3 March 2009 (UTC)

Possible plagiarist

There's a discussion going on about some possible plagiarism by Lantonov (talk · contribs) at WP:ANI#Plagiarist caught red-handed and refusing to cooperate. Among his contributions are some math articles: Hewitt–Savage zero-one law, Rook polynomial, Projective geometry, Eigenvalue, eigenvector and eigenspace, Hölder's inequality, Curvilinear coordinates, Pseudotensor and maybe others (I didn't go back through his whole edit history). It may be worthwhile for some project participants to check whether there are any problems with his additions to these articles. —David Eppstein (talk) 21:54, 3 March 2009 (UTC)

Hölder's inequality is fine; he just added a ref. (Hope it is ok to strike it off as done.) JackSchmidt (talk) 22:10, 3 March 2009 (UTC)
Most of his "AWB" edits that I have looked at are fine; they appear to just be letting the tool do its automatic cleanup. These are the 2008-02 ones. JackSchmidt (talk) 22:18, 3 March 2009 (UTC)
An article with a lot of edits from 2007 was Laplace transform. It looks ok to me, but I would not be able to recognize the problem there. He cites a book by Korn that might make it easy to check. Here are 10 or 20 consecutive edits. JackSchmidt (talk) 23:06, 3 March 2009 (UTC)
Hewitt-Savage zero-one law is okay. Rook polynomial is almost all Lantonov. On Projective geometry he made only one non-trivial edit, [1]. His contributions to Curvilinear coordinates are substantial. He has a few non-trivial contributions to pseudotensor, notably [2] and [3], but that's not an exhaustive list. He has lots of contributions to Eigenvalue, eigenvector, and eigenspace, but all the ones after 16:49, 25 March 2008 were either reverted or are okay. History of geometry is okay. Clifford bundle is okay. Manifold is okay. Cartesian coordinate system is okay. Covariant derivative is okay. Standard basis is okay. Lie derivative is okay. Loewner's torus inequality is okay. The relevant part of Laplace transform has been rewritten since his questionable additions. Aleph number is okay. Combinatorial proof is okay. Combinatorial species is okay. I think those are all of his math contributions which are not marked "AWB". Ozob (talk) 23:39, 3 March 2009 (UTC)
BTW, User:Gareth Owen should be thanked for his tireless corrections to Lantonov's edits at Eigenvalue, eigenvector, and eigenspace. Ozob (talk) 23:41, 3 March 2009 (UTC)

AfD for "History of quaternions"


I've nominated the article "History of quaternions" for deletion. The discussion page is Wikipedia:Articles for deletion/History of quaternions. --A. di M. (talk) 13:50, 28 February 2009 (UTC)

I would appreciate the opinions of mathematical editors on this topic. I see little accuracy, and much eloquence, on how quaternions are Good, but Oppressed, by modern vector analysis; if someone can read this and see more virtue, please do so. Septentrionalis PMAnderson 21:24, 2 March 2009 (UTC)

I would also appreciate more eyes on Classical Hamiltonian quaternions. It begins with a summary of Hamilton's own notation, which may well be sound, but continues into the same Quaternions Good, Vector Analysis Bad, as the article considered for deletion (it wasn't, but I redirected it - this may or may not hold). Septentrionalis PMAnderson 01:20, 5 March 2009 (UTC)

"Show new selections"

What is the link "Show new selections" on the mathematics project page good for? It links to the same site, but with an "action=purge" attached. Ringspectrum (talk) 15:52, 4 March 2009 (UTC)

"action=purge" forces the server to refresh the page. There may be some content on the page that isn't smart enough to refresh itself. In this case, it appears that asking the server to refresh the page causes a new article to be showed in the "Selected article". However, refreshing the browser does the same thing. It seems weird to force the server to refresh for such a process... hmm... Whereas simply refreshing your own browser will not change this. It does seem like a strange thing to have as such a process as a prominent link on the page... hmm... And just to be clear you're talking about the Math Portal, right? RobHar (talk) 16:02, 4 March 2009 (UTC)
"And just to be clear you're talking about the Math Portal, right?" Yes, thanks for the explanation. Ringspectrum (talk) 17:19, 4 March 2009 (UTC)
For the maths portal there quite a lot of content is selected at random, but the random numbers are only regenerated when the page is purged. --Salix (talk): 18:31, 4 March 2009 (UTC)

Cavalieri's principle

We finally have an article titled Cavalieri's principle. Happy editing! Michael Hardy (talk) 17:45, 5 March 2009 (UTC)

Nice. Should Method of indivisibles redirect there? —David Eppstein (talk) 18:47, 5 March 2009 (UTC)

OK, it now redirects. Michael Hardy (talk) 00:52, 6 March 2009 (UTC)

The vector of a quaternion

The vector of a quaternion has been sitting there for months. The article has obvious issues in regard to some of the usual Wikipedia conventions. Maybe it has other issues too. Michael Hardy (talk) 17:14, 6 March 2009 (UTC)

Lune of Hippocrates

Another new article for elementary geometry buffs to work on: Lune of Hippocrates. Michael Hardy (talk) 03:57, 7 March 2009 (UTC)

Manual of Style questions regarding TeX, displaystyle, and scriptstyle

Your collective comments and opinions would be greatly appreciated here: Wikipedia talk:Manual of Style (mathematics)#Using scriptstyle to make in-line symbols "fit". Thank you. -- Avi (talk) 18:59, 6 March 2009 (UTC)

<ping> Anyone have any comments? -- Avi (talk) 00:13, 9 March 2009 (UTC)

Infinite matrices

Is anybody knowledgeable in infinite matrices? In matrix (mathematics), I wrote a little section on that, but that may all well be POV, so I'm trying to find a good source for this topic. Who knows a book/book chapter on infinite matrices? Thanks, Jakob.scholbach (talk) 13:09, 7 March 2009 (UTC)

You might want to add a link to Hilbert space#Operators on Hilbert spaces to that section. JRSpriggs (talk) 15:40, 7 March 2009 (UTC)
In my opinion, your text is accurate, free of POV. Boris Tsirelson (talk) 18:43, 7 March 2009 (UTC)
Paul R. Halmos, "A Hilbert space problem book", ed. 2, Springer 1982. Chapter 5 "Infinite matrices". A quote from page 23: "Many problems about operators on finite-dimensional spaces can be solved with the aid of matrices; matrices reduce qualitative geometric statements to explicit algebraic computations. Not much of matrix theory carries over to infinite-dimensional spaces, and what does is not so useful, but it sometimes helps." Boris Tsirelson (talk) 18:46, 7 March 2009 (UTC)
Encyclopedic dictionary of mathematics, Second edition, ed. Kiyosi Itô, Math. Soc. Japan, 1993. Article 269 "Matrices" item K "Infinite matrices". Boris Tsirelson (talk) 18:51, 7 March 2009 (UTC)

love of digits

I hope this is the right place to mention — User: has been going through the polyhedron articles and changing every number-word (such as "one") to a numeral, as well as adding some strange alternate names such as "Heptagonal Deltahedron" for the triaugmented triangular prism. Can something be done? Should something be done? Am I getting over-excited about a petty matter of style? —Tamfang (talk) 04:01, 8 March 2009 (UTC)

usually the topic most likely to excite people on this page is style related. Who can forget the slanted and non-slanted d in derivative discussions? I would just revert all such edits. It's well-established to not use numerals in those cases, and any alternate names should be verifiable in some source. --C S (talk) 04:37, 10 March 2009 (UTC)

Boubaker polynomials (yet again)


See WP:ANI#Boubaker's polynomials (again) — it appears the same sockpuppets behind the mess in Wikipedia:Articles for deletion/Boubaker polynomials (3rd nomination) are back, again attempting to game Wikipedia:Notability (numbers) by inserting language implying that mentions of a sequence in unreliable web sources such as OEIS and PlanetMath is relevant to judging the notability of the subject here. In this diff, the editor in question asserts that ”Michael Hardy, Elehack , Robinh , Mazca , Troogleplex , Reyk ,VolkovBot, Jkasd, Popo le Chien and Asenine” are all in favor of the change (how the group in favor can include at least one bot is beyond me). The two socks in question have also made a number of edits to math articles but when I checked all were at the level of harmless punctuation changes. —David Eppstein (talk) 21:50, 8 March 2009 (UTC)

I was never consulted about the change and had no suspicion that that edit was to be done, so any suggestion that I am in favor of it is based on nothing. Michael Hardy (talk) 22:34, 8 March 2009 (UTC)

Some blocks and WP:Numbers has been semi-protected. I think that resolves it. --C S (talk) 04:34, 10 March 2009 (UTC)

Euclidean algorithm

Hi, I'm thinking of bringing the Euclidean algorithm to Good Article level. The topic seems small enough to be feasible, but has wide applications; it might make a good "cornerstone" article from which readers might begin to understand more advanced topics, especially in algebra. I was thinking of organizing the topic stepwise, beginning with integers (which many non-mathematical readers will understand) and advancing gradually to rationals, reals, polynomials, quadratic fields and then to general Euclidean domains. We might add applications such as some factorization algorithms and Sturm chains, and some generalizations such as Gröbner bases. If anyone wants to help, I'd appreciate it; thank you! Proteins (talk) 17:40, 11 March 2009 (UTC)

This is off-topic, but what is the Euclidean algorithm for real numbers? — Carl (CBM · talk) 01:58, 12 March 2009 (UTC)
In general, Euclid's algorithm applied to two real numbers a and b yields an infinite continued fraction (or equivalently an infinite series of convergents that are ever better approximations) to a/b. If I recall correctly, Euclid's second presentation of the algorithm in Book 10 of the Elements concerned real numbers, not integers. You might be interested in the article on integer relation algorithms. Proteins (talk) 04:31, 12 March 2009 (UTC)
If a > b are nonzero real numbers, the remainder of dividing a by b is 0, so I still have no idea what you are saying. Indeed, the section of that article that talks about continued fractions doesn't make sense, because there are no quotients in the Euclidean algorithm, only remainders. I'll leave a note on the talk page of the article. — Carl (CBM · talk) 05:11, 12 March 2009 (UTC)
I think what is meant is the Euclidean algorithm gives a way to generate the continued fraction of a rational number a/b. This process essentially consists of taking the integer part (if the rational is > 1) and then taking 1 over the reciprocal of the fractional part and then repeating with the reciprocal. This can of course be done with an arbitrary real number, not just a rational. So given a real r, take the integer part, then take the fractional part and then take 1/reciprocal and repeat (take integer part...). --C S (talk) 05:48, 12 March 2009 (UTC)
Ditto rational numbers. They are both fields, so surely the idea of a gcd doesn't make sense - everything is a divisor of everything else (give or take 0). I've done the Euclidean Algorithm for integers, polynomials and the general case (I'm not sure what is meant by a "quadratic field" in this context - a quadratic extension of the integers (which wouldn't be a field), perhaps? Is that significantly different to the general case?). The EA is a very important topic and certainly deserves a good article written about it, but let's be clear about what it does first! --Tango (talk) 02:13, 12 March 2009 (UTC)
You can apply it with real inputs, insisting that the quotients be integers, and then the remainders are real and smaller than the divisor. It then runs forever iff the ratio of the two inputs is irrational. Michael Hardy (talk) 05:46, 12 March 2009 (UTC)

Sorry, I was careless in using the term "quadratic field"; I meant the ring of quadratic integers.

I'm glad you agree that the EA is an important article to be improved, and I hope that you'll contribute. I'm afraid you'll have to expect a few mistakes from me, since I'm not a mathematician, and I'm just beginning to think through the topic. If you can be patient with my mistakes, I'll be patient with your corrections. ;) More generally, I'll be grateful for the help of anyone at this WikiProject in bringing the article to GA. Proteins (talk) 04:31, 12 March 2009 (UTC)

Concept algebra

It has been raised in an AfD here that this article could do with an expert eye so I am asking for an editor to give it the once over thanks. BigDuncTalk 20:27, 12 March 2009 (UTC)

Dyson's transform

Dyson's transform has been tagged for deletion (talk) 05:51, 13 March 2009 (UTC)

Indeed. It's a badly written article. An article should not be deleted because it's badly written; it should be re-written. Should this article be kept? I can't tell, because I don't know what Dyson's transform is, and whoever wrote the article is evidently unable to explain it. If someone here knows something, could they rewrite it if it's worth keeping and then remove the "prod" tag? Michael Hardy (talk) 13:47, 13 March 2009 (UTC)
Done! I rewrote it and removed the PROD and the other maintenance tags. I'm not sure it deserves its own article, but it's not clear what it might be merged into. Several related topics are in Schnirelmann density but don't really belong there. --Uncia (talk) 20:03, 13 March 2009 (UTC)

Helping Simple English With Maths?

Hello there, I know that the Simple English Wikipedia does not have a good standing with many EnWP editors; I just tried to make the article on the Riemann hypothesis (on Simple) better, but I am not from hard-line, pure mathematics (but applied maths). Anyway, we would like to welcome any editors wanting to help us with mathematics-related topics. --Eptalon (talk) 12:55, 13 March 2009 (UTC)

WikiProject Council

Does anyone here have any interest in Wikipedia:WikiProject Council or Wikipedia:WikiProject Council/Assessment working group? Michael Hardy (talk) 16:41, 12 March 2009 (UTC)

I sometimes look at the council page, but I haven't participated much in the recent assessment discussions. I suppose I should find out what is happening with them and then make a summary here. — Carl (CBM · talk) 14:09, 15 March 2009 (UTC)

Template: WikiProject Mathematics

{{WikiProject Mathematics}} is broken after a recent bot update. (talk) 05:50, 13 March 2009 (UTC)

It seems fine now. Template:WikiProject Mathematics should not be used; the correct name is Template:Maths rating (or Template:Math rating). The idea is to subtly remind people that the point of these is to assign quality and importance ratings. — Carl (CBM · talk) 14:07, 15 March 2009 (UTC)

Categories of categories

Perhaps someone could have a look at this cfd. There is some abuse of notation involved in the category structure – putting a category C at the bottom of an article X means 'X is a member of C'; putting a category C at the bottom of a category D usually means 'D is a subcategory of C'. However when we put A = Category:Categories named after criminals at the bottom of B = Category:Al Capone the meaning can only be 'B is a member of A' (not 'B is a subcat of A'). Of course I may be wrong about this and if so perhaps someone could explain my error to me. Occuli (talk) 16:32, 13 March 2009 (UTC)

What does this have to do with mathematics? Algebraist 20:24, 13 March 2009 (UTC)
If it spills over from criminals into Category:Category-theoretic categories it might start affecting us. —David Eppstein (talk) 21:12, 13 March 2009 (UTC)
I don't see any "named after" categories in the List_of_mathematics_categories. — Carl (CBM · talk) 00:23, 15 March 2009 (UTC)
We could always try starting Category:Categories named after category-theoretic categories... —David Eppstein (talk) 00:25, 15 March 2009 (UTC)

Article alerts

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Thanks. — Headbomb {ταλκκοντριβς – WP Physics} 09:23, 15 March, 2009 (UTC)

I know this is an automated announcement, but people may not know that that this is essentially a duplicate of Wikipedia:WikiProject Mathematics/Current activity, except that the article alerts system relies on having talk page tags while the current activity system uses the ordinary category system on the articles themselves. So we probably do not need to subscribe to the article alerts system. — Carl (CBM · talk) 14:05, 15 March 2009 (UTC)

Knot theory FAC

Knot theory has been nominated for Featured Article. See Wikipedia:Featured_article_candidates/Knot_theory. --C S (talk) 10:45, 15 March 2009 (UTC)

recent edit to Wedderburn's little theorem

Can someone help me with this Talk:Wedderburn's little theorem, please? Ringspectrum (talk) 18:15, 15 March 2009 (UTC)


The unmistakable behavioural patterns of Katsushi in Riemann hypothesis, as well as the choice of the topic, makes me believe that the user is a sockpuppet of our friend User:WAREL. Shall we do something about it? — Emil J. 12:36, 12 March 2009 (UTC)

I came to the same conclusion. Unfortunately, I can't block him myself since I reverted one of his edits. -- Jitse Niesen (talk) 13:11, 12 March 2009 (UTC)

Some editors are under the impression that Warel is a banned user. This doesn't seem to be the case (although I had thought so too). --C S (talk) 02:42, 13 March 2009 (UTC)

It doesn't seem so, although he has been blocked long-term multiple times. See Category:Suspected Wikipedia sockpuppets of WAREL, Wikipedia:Requests for comment/WAREL, Wikipedia:Administrators' noticeboard/IncidentArchive88#Indef block of WAREL/DYLAN LENNON, Wikipedia:Administrators' noticeboard/IncidentArchive126#User:WAREL is back, and Wikipedia:Administrators' noticeboard/IncidentArchive138#User:WATARU, etc.. —David Eppstein (talk) 03:08, 13 March 2009 (UTC)
Over at WP:Sockpuppet investigations, my impression is that accounts that cause this much trouble are usually blocked indefinitely. Are there diffs to show Katsushi acting like WAREL, for instance on Riemann hypothesis? Can anyone collect a set of diffs here that would be complete enough to justify a block by any random admin? (so that they don't have to go through all the talk archives of this page). Or, as an alternative does anyone have the patience to make a filing at WP:SPI? EdJohnston (talk) 04:12, 13 March 2009 (UTC)
Since peculiar edits to math articles have continued after a warning, with no response at all, I've blocked Katsushi indef as a sock of User:WAREL. I welcome review of this block. Other admins may modify the block as they think appropriate. EdJohnston (talk) 06:14, 19 March 2009 (UTC)
I found Katsushi basically easy to work with, and that his edits always had merit (but that a revert always left the article in a better state). His contributions to the Riemann hypothesis article both pointed out a deficiency in the given sources (though one that was trivially fixed with other common sources) and a useful source for the expansion of the divisor function article. In particular, I believe he did read talk pages and did modify his actions accordingly. I don't think many editors tried to discuss things with him, but those that did (either on his talk page or on the article talk page) did not get any easy to read response. I don't disagree with the block or the ban (especially of repeatedly editing the article without discussion), but I would caution that his edits do not appear malicious or horribly ill-informed. They are merely "peculiar", sometimes of questionable style, but most importantly unexplained. JackSchmidt (talk) 07:13, 19 March 2009 (UTC)

LaTeX to Wiki conversion

I haven't had a chance to try it yet, but this blog post (from the maintainer of the polymath wiki) concerning an automated tool for converting LaTeX-formatted documents to wiki-formatting looks like it could be of interest to editors here. —David Eppstein (talk) 21:08, 19 March 2009 (UTC)

mistake in Perfect map

"if the perfect image (image under a perfect map) of a certain space X is connected, then X must be connected." A counterexample is given in Examples and properties, 6.

Does anyone know if the statement becomes true if we add "the preimage of every point of Y is connected" (or something like that) as a hypothesis? Ringspectrum (talk) 06:10, 20 March 2009 (UTC)

Help wanted: documenting divergences between constructive and classical maths

On the talk page for Constructivism (mathematics) I wrote:

I have an idea that the article would benefit immensely from a more hands-on account of where classical and constructive mathematics diverge, organised on a thematic basis. The kind of thing I have in mind is to say that, say, in measure theory, how the accepting or rejecting AC gives different worlds, where classical measure theory is interested in the complexity of constructions of non-measurable sets, and constructive measure theory is concerned with things like integration of functions over notions of the computable real line. Doing this properly is well beyond my mathematical-recreations pay grade, though. I'd appreciate some help in coming up with a good set of topics. My initial ideas are:
  1. The above bit on measure theory and Lebesgue integration;
  2. Analysis and Specker's theorem;
  3. Maybe there's something interesting in ideal theory and Buchberger's computable algebra?

This little enterprise might be of interest to folks not orbiting the constructive maths-think bubble. All help appreciated. It's probably best to reply on Talk:Constructivism (mathematics)Charles Stewart (talk) 14:44, 20 March 2009 (UTC)


There is an attempt to introduce mathematical jargon into the first line of our A-class article Manifold. Please, comment at Talk:Manifold. Arcfrk (talk) 17:58, 20 March 2009 (UTC)

Donsker's theorem

Can someone address the question I raised at talk:Donsker's theorem? Michael Hardy (talk) 11:58, 21 March 2009 (UTC)

I did. You are right (as usual). Please look now. Boris Tsirelson (talk) 17:11, 21 March 2009 (UTC)

A small lesson in math typestetting

Look at the way this article appeared BEFORE this edit. Someone intended a period at the end of the "displayed" TeX, which consisted of several lines in the "align" environment. The period was OUTSIDE of the <math> tags, and was slightly above one of the lines in the MIDDLE! Moral: TeX on Wikipedia doesn't work like TeX in NORMAL use. Michael Hardy (talk) 23:12, 21 March 2009 (UTC)

Duality (mathematics) collaboration

I remember an attempt -- quite successful, IMO -- to bring an article with more involved mathematics, namely homotopy groups of spheres, to a decent (GA) standard. I'd like to propose another such collaboration, and would be glad if many people join in. The topic I propose is duality (this is waiting as a COTM, too), so something (m)any of you will have encountered, but it looks like a subject where having contributors from many mathematical backgrounds is highly beneficial (more so than as usual). Who is willing to join in? I think a reasonable aim would be Good Article level. Jakob.scholbach (talk) 17:37, 10 March 2009 (UTC)

I think it's a great aim, I will try to help. But I have a question. It's currently a bit like a list of subjects under the heading "duality". It seems one main goal should be to explain how all these dualities are really coming from the same idea, namely that a linear functional can be identified with a vector. At least I think I haven't seen any duality theory where the main idea was not this. Has anyone? --GaborPete (talk) 17:20, 17 March 2009 (UTC)
Sets are dual with their complements, and the set intersection and union operators are dual; this is analogous to the logical duality of ∧ and ∨. This duality does not seem to me to have any obvious connection with vectors and functionals. The article mentions dualities between high- and low-dimension components of polyhedra, graphs, and planar configurations. I wonder if explaining these in terms of vector spaces and functionals would really be to the point. Not mentioned on the page are logical dualities between ∀ and ∃, and between certain pairs of modal logical operators such as ⋄ and □. I would be fascinated and astonished to see these explained in terms of vector spaces.
I happened to read (Gowers, Timothy (2008), "III.19 Duality", The Princeton Companion to Mathematics, Princeton University Press, pp. 187–190 ) last night, and was interested to see that Gowers presented no general theory or explanation of duality either. —Dominus (talk) 19:05, 17 March 2009 (UTC)
There is a (non-obvious and somewhat tenuous) connection between logical/Boolean duality and vector space duality, via linear logic. But even so, it is quite a stretch to claim that De Morgan's laws "really come from" linear algebra ... –Henning Makholm (talk) 20:28, 17 March 2009 (UTC)
There might be an interpretation of set-theoretic duality via vector spaces using the field with one element. But I'm kind of doubtful because duality in the sense of vector spaces never changes the dimension, whereas the complement of a set usually has a different cardinality from the original set. (It doesn't help that the foundational stuff surrounding F1 is still very mysterious.) Ozob (talk) 21:40, 23 March 2009 (UTC)
It also occurs to me that the relationship between provability and satisfiability has probably also been considered a duality. —Dominus (talk) 20:56, 17 March 2009 (UTC) (Addendum: it has. —Dominus (talk) 21:02, 17 March 2009 (UTC))

Panos Papasoglu on AfD

I don't know why Jitse's bot hasn't been picking this one up for the current activity page, but: Panos Papasoglu, an article on a Greek geometric group theorist, has been up for deletion for a few days now already. There's still time to comment before it closes, but probably not for much longer. Discussion is here. —David Eppstein (talk) 03:43, 23 March 2009 (UTC)

Jitse's bot seems to have been asleep for a few days. Michael Hardy (talk) 07:06, 23 March 2009 (UTC)

Logarithmically-spaced Dirac comb

Logarithmically-spaced Dirac comb has been prodded for deletion . (talk) 06:07, 24 March 2009 (UTC)

Catalog of articles in probability theory versus List of probability topics

In the end of 2008 I have found the List of probability topics in a somewhat neglected state; see Talk:List_of_probability_topics#A:_Articles_missing_from_the_List_of_probability_topics and Talk:List_of_probability_topics#Organize_the_list. I tried taking care of it, but was still unhappy. Thus, in December 2008 I have created a new version named Catalog of articles in probability theory. Just look on both and see the difference. It was suggested once (in December 2008) to merge the new list into the old one, but this did not happen, still.

It seems clear to me that this new experimental format has some advantages (at least in this case); however, it has an important drawback: it is computer-assisted, thus, it should not be edited manually. Instead, one should edit its source (for now, see User:Tsirel/Catalog source; ultimately it should be "Talk:Catalog_of_articles_in_probability_theory/Source") and call a bot that formats the source and rewrites the "Catalog". Such a program is written (see the source User:Tsirel/Bot code and parameters User:Tsirel/Bot parameters); for now, I run it myself. Ultimately it should be callable by anyone, similarly to the "mathbot" by Oleg Alexandrov, instrumental to both lists of probability articles, "traditional" and experimental (and to many other mathematical lists, of course). See also my exchange with Oleg Alexandrov User_talk:Oleg_Alexandrov#Another_bot_needed?

Thus, I am asking approval of my new bot, CataBotTsirel, see Wikipedia:Bots/Requests_for_approval/CataBotTsirel. Naturally, the Bot Approvals Group is wondering whether WikiProject Mathematics finds my experiment interesting, or not. Your comments are welcome! Boris Tsirelson (talk) 08:37, 16 March 2009 (UTC)

The bot is already approved for trial (7 days); I use it, see User talk:CataBotTsirel. You are welcome to edit the "Catalog", but indirectly, as explained in its lead. It may happen that you want edit some headings etc; in this case, edit User:Tsirel/Bot parameters (respecting the syntax). Boris Tsirelson (talk) 20:59, 16 March 2009 (UTC)

I find your catalog well designed (somewhat complementary to the old list; I'd oppose a simple merger). I'd support using the bot on regular basis. At some stage, however, you may want to devote some time to document the "protocol" to assure that anyone can understand it and modify the page (via the source) and anyone can easily understand the codes/abbreviations used on the page. ptrf (talk) 09:21, 18 March 2009 (UTC)
Thank you. Indeed, the explanations should be better. But I guess that you do understand all that, and maybe you can write the explanations better than me! (Not that I am so lazy, but really, the developer is often not the best person to explain.) I am the initiator, not the owner of all that. (Except for the bot, of course; regretfully, for now I am its owner.) Boris Tsirelson (talk) 09:38, 18 March 2009 (UTC)
I'll think about it (please be patient, though). ptrf (talk) 10:53, 18 March 2009 (UTC)

The bot is on trial for 7 more days. Boris Tsirelson (talk) 11:44, 25 March 2009 (UTC)

Help explain proof of Fermat's Last Theorem

Please help with Wiles's proof of Fermat's Last Theorem. I am trying to use Wikipedia's strengths to make this a really useful article for the non-professional.--Lagelspeil (talk) 09:36, 16 March 2009 (UTC)

Looks basic enough to me without removing the really important bits. To write a really good article, you probably have to know the proof and understand it deeply. That is to say, you know the crucial bits and can explain them in a relatively easy manner (without going into complicated algebraic geometry). But really, many professionals want to get something out of the article so try not to make it too trivial. --PST 11:53, 16 March 2009 (UTC)
I suspect that the professionals are not in need of Wikipedia. They can get through the Wiles paper on their own. It is really for the college scientist or engineer (or bright and determined high school student) that Wikipedia should aim for. The problem is that the Wiles style aims for the professional and leaves the non-professional to grope around in order to recognize this or that notation. Between that, the NOVA/Horizons program and other on-line resources, what the next level (downwards) of reader needs is a key to explain that when you encounter this or that notation, it points to a specific English-word subject area and WP page. Of course, it is the very rare layman who has any new feedback to offer the article, but I am trying to play to Wikipedia's strengths in helping one to actually plough or at least skim through the entire paper and develop, if not a sense of mastery, then a least a sense of familiarity. That is one thing that an encyclopedia should do: ask the young or flexible reader: should perhaps you become a professional in this subject area? That is what sharing knowledge should be about. The implied message should be: "Don't stop. Keep going. Here is some help."--Lagelspeil (talk) 04:30, 17 March 2009 (UTC)
Believe it or not, many professionals whose expertise is not in precisely the same area of mathematics find Wikipedia useful, as a gentler way of starting to learn about subjects that they are not already familiar enough with to read the technical papers easily, and also as a way of finding out which technical papers to read and which ideas in a subject are the important ones. Please don't make it less useful for them in your attempts to make it more useful for others. You are not the only target audience. —David Eppstein (talk) 05:10, 17 March 2009 (UTC)
Indeed; and I am an example. However, what about peaceful coexistence of an "easy" part and a "hard" part of an article? Boris Tsirelson (talk) 06:40, 17 March 2009 (UTC)
Not unlike the "progress of previous decades" and "Wiles proof" sections already present in the article? —David Eppstein (talk) 07:02, 17 March 2009 (UTC)
I most certainly agree. If professionals are not in need of Wikipedia, then who writes the articles around here? --PST 23:42, 17 March 2009 (UTC)
Lagelspeil, although I like your aim, I think there are some serious problems with your edit. First of all, that paragraph in Wiles proof is certainly not at the right place: the paragraph after it is a direct continuation of the paragraph before it, so your paragraph is very disruptive. Then, I'm not sure that the list you are providing is helpful for anyone. It is a quite random collection of links to some of the basic notions used in the article. lt's something like having a link to every single English letter in the middle of an article on a Shakespeare drama. I would say that a more natural way for a non-professional reader to explore the math background of such an article is to read the leading paragraph, follow the links from there to larger and more basic topics, and so on. Of course, the leading paragraph has to be carefully written for this. And, of course, it still would be very valuable to provide a good popular science account of the proof, for example explaining how geometry comes into the proof and what type of geometry that is. --GaborPete (talk) 07:32, 17 March 2009 (UTC)
Let me add that my analogy with the Shakespeare article makes sense only if it's on the Chinese wikipedia, say. There the English letters would contain non-trivial information, but still, it wouldn't be the right place for them. --GaborPete (talk) 17:10, 17 March 2009 (UTC)

Well, this issue could more readily be settled if an arithmetic geometer were available to comment on the article (rather than on the overall state of Wikipedia). Maybe User:RobHar? The article in question is worthy, and could use improvement on both the "high" and "low" ends. Acannas (talk) 00:47, 18 March 2009 (UTC)

I have incorporated some of your feedback. Yes, some of the text was choppy because it was a cut-and-paste merge of the text we had in the FLT and Wiles articles. Both of those other two articles now have a much more focused feel to them. I have put in a final section called a "Reading and notation guide" so that the motivated reader can ramp up to the 100-pager with some expert reviews. Still, it is justified to give the naive reader some warning that they are embarking on a somewhat long road from knowing little-to-nothing about abstract algebra and getting to understand some parts of the proof. Some know-it-alls will attempt it, just like Mt. Everest.--Lagelspeil (talk) 14:39, 25 March 2009 (UTC)

AfD Elegant Exponents

I nominated Elegant Exponents for deletion. A couple of people on te discussion in WP:Articles for deletion/Elegant Exponents have talked about merging the useful content into exponentiaion. I don't think there is any useful content and wonder why a person expended effort on it in it first place, but I'm raising it here as stranger things than my being wrong have happened before now. Dmcq (talk) 18:23, 24 March 2009 (UTC)

Calculus on manifolds (disambiguation)

Calculus on manifolds was until moments ago a redirect to differential geometry. I"ve changed it to a disambiguation page listing that and also differentiable manifold and Calculus on Manifolds (book). Michael Hardy (talk) 13:43, 25 March 2009 (UTC)

.....and then I found that Calculus on Manifolds (with a capital initial "M") redirected to differential geometry, despite the fact that capitalization of the "M" matches the book title. I've now redirected it to calculus on manifolds, the new disambiguation page. Michael Hardy (talk) 13:46, 25 March 2009 (UTC)

Problematic article

The article on supernatural numbers confuses two very separate notions (formal products of infinitely many primes, versus elements of nonstandard models of arithmetic). Not sure what is the best course of action. --Trovatore (talk) 17:10, 26 March 2009 (UTC)

Take out the stuff on generalized natural numbers, if that's what the formal products are actually called, and make a separate article. Both will be stubs, but so be it. Septentrionalis PMAnderson 22:58, 26 March 2009 (UTC)
Actually I think it's the other way around — Hofstadter's terminology (for nonstandard natural number) is apparently unique to him (and those quoting him), whereas Algebraist finds that the infinite-formal-product meaning is actually in use. --Trovatore (talk) 00:06, 27 March 2009 (UTC)
Going by Google Books, 'generalized natural number' seems to not be much used, while most authors just call all the formal products supernaturals (even the ones that correspond to naturals). Algebraist 00:16, 27 March 2009 (UTC)

Frequently viewed math articles

The list Wikipedia:WikiProject_Mathematics/Wikipedia_1.0/Frequently_viewed/List is quite interesting, I think, but outdated by roughly a year. Could somebody update that list? Jakob.scholbach (talk) 12:40, 28 March 2009 (UTC)

That somebody would probably have to be me. I do know it's somewhat outdated. I'll see what I can do, but it may be a few days. I have a sense that the vast majority will stay the same, which is why I don't think there's a need for any sort of automated updates. — Carl (CBM · talk) 12:57, 28 March 2009 (UTC)
Thanks muchly; and do take your time. You are right, it's not at all urgent. Jakob.scholbach (talk) 13:32, 28 March 2009 (UTC)

Frank Grosshans

The article titled Frank Grosshans is

  • a near-orphan (only two other articles link to it); and
  • being considered for deletion.

If you offer an opinion in the deletion discussion, don't just say Keep or Delete; also give your arguments. The discussion is here: Wikipedia:Articles for deletion/Frank Grosshans. Michael Hardy (talk) 03:34, 31 March 2009 (UTC)

Just barely not a disambiguation page?

In the article titled Mollweide's formula, I wrote:

Mollweide's formula can be used to check solutions of triangles.

I wanted to link to solution of triangles or whatever the suitable title is, but we had no such article.

Why should there be such an article when we already have law of sines and law of cosines, and those two cover it all, and in addition we have law of tangents?

A new article just to link to all of those seems a bit like a disambiguation page, since the articles it links to are where the substantial material is.

But it seems to me there could be a dozen or so articles that refer to the concept of solution of triangles, where it would be appropriate to link to an article explaining what that is, so the new not-quite-disambiguation page should be there. And now it is. Michael Hardy (talk) 23:36, 31 March 2009 (UTC)

Definition of curl

There is an ongoing dispute in the Curl (mathematics) article over the proper definition of the curl (see Talk:Curl (mathematics)#Definition of Curl). I imagine that an outside opinion would be helpful. Jim (talk) 05:33, 1 April 2009 (UTC)