# Jan 2010

## Error in http://en.wikipedia.org/wiki/Plane_(geometry)?

This is my first attempt to participate in Wikipedia, so please let me know if I get something wrong. I wasn't brave enough to edit the page directly.

I believe that I spotted an error in the Plane(geometry) page.

In the section
Define a plane with a point and two vectors lying on it

the equation
r = r0 + sv + tw

should be
r = r0 + s(v - r0) +t(w - r0) --Rtgjr (talk) 20:52, 26 December 2009 (UTC)

The place for this is the article's talk page. The article is correct. I'll reply to the user's own talk page. ~~ Dr Dec (Talk) ~~ 21:47, 26 December 2009 (UTC)
Do not worry about making mistakes; everyone makes a mistake at some point. Even in the case that one does make a mistake in an article, it is often easily fixed. Your contributions are always appreciated. --PST 12:54, 27 December 2009 (UTC)

## Unitary space

I just replaced a (somewhat misleading) redirect from Unitary space to Hilbert space with a (very short) stub. Can someone review the article (err... have a look at the two sentences), and possibly add some more details to it?  Cs32en  05:21, 27 December 2009 (UTC)

A redirect to inner product space is more appropriate I think (if indeed unitary spaces are not complete by definition—someone needs to look into this). Also, a norm is already defined on every inner product space, so "inner product space on which a norm is defined" is a distinction that does not exist anywhere in the literature. This is like saying "a Banach space with a metric" or "a metric space with a topology". Having an inner product is a strictly stronger condition than having a norm. We have already had a similar discussion before at Talk:Hilbert space#Pre-Hilbert space many months ago. Sławomir Biały (talk) 12:55, 27 December 2009 (UTC)
An inner product space is a space on which a scalar product is defined. The existence of a scalar product does not imply the existence of a norm, so having an inner product is not a strictly stronger condition than having a norm.

12.4.1.2 Unitary spaces and their properties
In a pre-Hilbert space, one can, with the help of the scalar product, create a norm [...].
(Bronstein et al., Taschenbuch der Mathematik, 7. ed., 2008, p. 678)

Why didn't you wait for some more input in this discussion before editing the article? I don't think accusing me of original research when I was explicitly referring to a source is appropriate.  Cs32en  19:32, 27 December 2009 (UTC)
An inner product trivially leads to a norm. If the inner product is denoted as <x,y> then define norm(x)=sqrt(<x,x>). But there are normed spaces where no inner product can be defined. I think that is what User:Sławomir Biały meant by a strictly stronger condition. Your statement "The existence of a scalar product does not imply the existence of a norm" is just wrong, assuming you use the phrase "scalar product" to mean "inner product". --Robin (talk) 19:50, 27 December 2009 (UTC)
What if you have a pre-Hilbert space on $\mathbb Q$? Then a norm such as $\sqrt{}$ does not exist in $\mathbb Q$ Cs32en  20:32, 27 December 2009 (UTC)
Well, WP:OR often occurs when the source doesn't support the statement being made. Since we've been over this already, I have taken the rhetoric up a notch. Also, waiting until more discussion before making an edit is not mandatory (refer to WP:BRD), particularly when (unless I am very mistaken) this one is likely to be very uncontroversial here. Otherwise, you are of course free to find a reliable source that unequivocally supports the statement that "The existence of [an inner product] does not imply the existence of a norm." Sławomir Biały (talk) 21:06, 27 December 2009 (UTC)
Is there a reliable source that unequivocally says that an inner product does imply the existence of a norm for all vector spaces (i.e. not only for vector spaces defined, for example, on the real numbers)?  Cs32en  21:24, 27 December 2009 (UTC)
In every linear algebra book I've read, inner product spaces are defined only over R and C. In fact, see the Mathworld article which says "An inner product on a vector space V over a field K (which must be either the field R of real numbers or the field C of complex numbers)" [1]. The article also clearly states that "Every inner product space is a normed vector space". --Robin (talk) 21:33, 27 December 2009 (UTC)
James and James, Mathematics Dictionary, 5. ed., 1992, p. 219, say: "inner-product space. A vector space V on which there is a function (called a the inner product or scalar product) whose domain is in the set of ordered pairs of V, whose range is in the set of scalars (real or complex numbers) [...]. If a norm is defined by $\lVert x\rVert = (x,x)^{1/2}$, then the space becomes a normed vector space."
While not unequivocal, James and James thus imply ("If a norm is defined") that such a norm might not be defined in any inner product space. On the other hand, they state that the inner product is in the range of real or complex numbers, which might be understood as implying that the vector space must be defined on either $\mathbb R$ or $\mathbb C$ as well. (Note, however, that if the range of a scalar product is in $\mathbb Q$, then it would also be in $\mathbb R$ and $\mathbb C$.)  Cs32en  21:57, 27 December 2009 (UTC)
As far as I can tell, no one else is talking about inner product spaces over fields besides R or C, even the very sources that you have cited. An inner product is a special case of the more general notion of bilinear form, which is defined over more general fields. We already have appropriate articles in agreement with uncontroversial mathematical usage. Also, I read the "if" in the James and James reference as a "let" as is typical in English mathematical writing, so I do not accept this as a counterexample, and certainly not the kind of unequivocal statement that would be needed. Sławomir Biały (talk) 22:20, 27 December 2009 (UTC)
Let us assume that "if" actually means "let" in that source. How do you explain why the authors chose to use the language "becomes a normed vector space"? What was the inner product space before becoming a normed vector space? Bronstein et al., p. 678, say: "A vector space defined on the field $\mathbb K$ (in most cases $\mathbb C$ is being considered) is being called [...] an inner product space [if an inner product exists]." A field $\mathbb K$ does not need to be either $\mathbb R$ or $\mathbb C$ Cs32en  23:02, 27 December 2009 (UTC)
Also, if every inner product space would be defined on either $\mathbb R$ or $\mathbb C$, then every inner product space would be complete, and thus, if we combine this with the assumption that every inner-product space would be a normed vector space with the norm given by $\sqrt{}$, i.e. a unitary space, every inner product space would be a Hilbert space.  Cs32en  22:08, 27 December 2009 (UTC)
I must disagree. For instance, the set of all complex polynomials on [−1,1] equipped with the inner product $\langle f,g\rangle = \int_{-1}^1 f(t)\overline{g(t)}\,dt$ is an inner product space (with complex inner product) that is not complete. The completion is L2[−1,1]. It might be helpful to digest the distinction between a Hilbert space and a pre-Hilbert space before attempting to create new articles on the subject. Sławomir Biały (talk) 22:20, 27 December 2009 (UTC)
Of course, if you define an inner product space on a set $D_1 \subset \mathbb R$ or a set $D_2 \subset \mathbb C$, then such an inner product space does not need to be complete.  Cs32en  23:02, 27 December 2009 (UTC)
Such a "space" would not even be a vector space over R or C, so obviously not an inner product space. Sławomir Biały (talk) 23:08, 27 December 2009 (UTC)
Just to repeat, the difference between a Hilbert space and any old inner product space is the completeness condition. It has nothing to do with norms. Both spaces are normed spaces. --Robin (talk) 23:25, 27 December 2009 (UTC)
Indeed. And as WP:STICK is becoming increasingly relevant in this thread, here is another question for Cs32en: Does Cs believe that every inner product space over the real or complex numbers is complete (with the induced norm), and therefore is a Hilbert space? Presumably this is what the above is intended to mean: "Also, if every inner product space would be defined on either $\mathbb R$ or $\mathbb C$, then every inner product space would be complete." Sławomir Biały (talk) 00:12, 28 December 2009 (UTC)
$\mathbb R^n$ and $\mathbb C^n$ are Hilbert spaces.  Cs32en  01:09, 28 December 2009 (UTC)
You didn't answer my question. Sławomir Biały (talk) 01:16, 28 December 2009 (UTC)
You misrepresented my statements and came up with a question that is poorly defined (what kind of norm are we talking about, to begin with). I will not answer this question and thereby open up further possibilities for the continuation of such a type of discussion. I already said that I am not going to discuss this further (see below).  Cs32en  01:27, 28 December 2009 (UTC)
(@ Slawomir): For a vector space defined on $\mathbb Q \subset \mathbb R$, the vector space axioms are true. Kaye and Wilson, Linear Algebra, 1992, even give the example of a vector space based on $\{0\}$ Cs32en  23:37, 27 December 2009 (UTC)
Let me respond here with a question: Do you believe that Q, the field of rational numbers, is a vector space over the reals or complex numbers? Sławomir Biały (talk) 23:58, 27 December 2009 (UTC)
I'm not sure how this helps to solve the problem. $\mathbb Q$ is not a vector space over $\mathbb R$, because there is no vector $kv \in \mathbb Q\;\forall\; k \in \mathbb R, v \in \mathbb Q$ Cs32en  00:26, 28 December 2009 (UTC)

(unindent) Just to recap. Cs32en claimed that any inner product space over R or C is complete. When it was pointed out that this was not the case, Cs32en then said that subsets of R and C can be given an "inner product". To this, I then replied that subsets of R and C (excluding of course the zero subspace) are not vector spaces over R or C (and [[a fortiori] are not inner product spaces). To this, Cs responded that Q is a vector space over R or C, and claimed to give a reference in support of this statement. Then, when pressed, Cs agreed that Q is not a vector space over R or C.

This is too much. Please, Cs32en, give a clear statement of what it is that you believe to be true, supported by unambiguous references that do not require us to psychoanalyze the usage of particular words (like "if", "can be given", etc.) Until this time, I shall observe WP:STICK and leave this discussion because it is just as unproductive (and indeed getting to be much longer and more absurd) than even the one at Talk:Hilbert space that covered the same ground. Sławomir Biały (talk) 00:41, 28 December 2009 (UTC)

I have never stated that $\mathbb Q$ would be a vector space over $\mathbb R$ or $\mathbb C$. Your summary of the discussion is highly misleading. I will not go into the details here. I do not appreciate your patronizing language, and I will therefore discontinue this discussion at this point.  Cs32en  01:09, 28 December 2009 (UTC)

### Ultrametric norms

Just to confuse things again: the following paper discusses p-adic Hilbert spaces and p-adic inner products: Operator Calculus For p-Adic Valued Symbols And Quantization, S. Albeverio, R. Cianci and A.Yu. Khrennikov, Rend. Sem. Mat. Univ. Pol. Torino, Vol. 67, 2 (2009), 137 – 150, Second Conf. Pseudo-Differential Operators. This doesn't change the fact that real or complex inner product spaces induce a norm, or that non-complete spaces can have an inner product, or that normed spaces need not have an inner product. Charvest (talk) 22:48, 27 December 2009 (UTC)

Strangely we seem to lack a proper article on ultrametric norms. This is a serious omission. Sławomir Biały (talk) 01:42, 28 December 2009 (UTC)
Ultrametric space seems to be all we have. Algebraist 02:03, 28 December 2009 (UTC)

## Need additional eyes on Ratio

I've been trying to improve the Ratio article but I'm having a weird argument with another editor who insists on putting incorrect information in it. Anyone care to chime in on the talk page?--RDBury (talk) 00:43, 28 December 2009 (UTC)

I support your view on what a ratio is, and I haven't see any other definition in the literature. I've looked at the talk page, and there are comments from other people as well who interpret a ratio to represent $\frac{f(x)}{g(y)}$ or $\frac{f(x,y)}{g(x,y)}$, rather than $\frac x y$ Cs32en  02:36, 28 December 2009 (UTC)

We now have articles for Seventh dimension, Eighth dimension and Ninth dimension. Some other dimension articles have been created that were formerly redirects. This seems to be part of a general trend of copy, paste, and add one type articles in WPM. In general, I think a very narrow interpretation of the WP:GNG should be used with these. Multiple articles with nearly the same content are not encyclopedic, not useful and generally look bad. A big problem is that people see articles like Fifth dimension and Sixth dimension and, using the WP:Other stuff exists argument, automatically assume that we need to keep adding articles in the series until Wikipedia runs out of server space. The GNG is supposed to prevent this kind of thing but some of the mathematical articles that already exist set a bad example. There are plenty of notable subjects at Wikipedia:Missing science topics that need articles, and we shouldn't be wasting time and effort writing and maintaining articles simply because there is a series of similar articles.--RDBury (talk) 14:44, 26 December 2009 (UTC)

Sorry to intrude by cutting apart discussion like this, but it's only the lead section that is always nearly the same. Nine-dimensional space is the weakest of the lot, certainly, as it isn't used in scientific theories...but all the rest are! 4 = 2 + 2 04:18, 29 December 2009 (UTC)
I noticed this. They are copy and paste jobs from a two day old snapshot of my re-write of sixth dimension, except with random non-notable, often non-scientific additions to them, numerous problems with copying and pasting (e.g. not changing a 6 to another digit in a few places). As for notability I agree: after coming up with a handful of things for sixth dimension I can't think of anything as useful for the others. The only one that I would be happy with the Seven-dimensional cross product, but it already has its own article. --JohnBlackburne (talk) 20:40, 26 December 2009 (UTC)
Another example: Hexatope numbers, C&P of Pentatope number. This just came up in current activity as being PRODed. But it doesn't seem to meet Wikipedia:Criteria for speedy deletion so I doubt the PROD will be accepted, so that means an AfD battle.--RDBury (talk) 11:57, 27 December 2009 (UTC)
Grumble. It's worse than I thought. For most values of m, almost all of mth dimension' should be in m-dimensional space, (with almost all of the rest unsourced nonsense), and almost all of that should be already in n-dimensional space. I've proposed deletion of 7-9, changed 1-3 back to redirects, and commented on 5-6. 4th dimension.
I've also proposed deletion of sextic equation and septic equation. It's likely 4 will remove the prods, but an AfD is likely in order. — Arthur Rubin (talk) 09:03, 28 December 2009 (UTC)
Um...nonsense? I was trying to add some useful content to the articles. 4 = 2 + 2 14:24, 28 December 2009 (UTC)
It appears as though all of your prods have been removed, most of them summarily by 4, and one by Colonel Warden. Since Warden's purported refutation of the prod is the role played by sextic equations in Hilbert's 13th problem, perhaps a redirect is in order instead. Sławomir Biały (talk) 12:40, 28 December 2009 (UTC)
I'm the one responsible for all of this. See fifth dimension and sixth dimension, though: maybe all these lower dimensions should be going to "m-dimensional space". In fact, that's what I'm going to do now. 4 = 2 + 2 12:43, 28 December 2009 (UTC)
But of course, I'm going to wait till people here say "yes" or "no". I have put the 1D, 2D & 3D articles at 1D space, 2D space and 3D space. 4 = 2 + 2 12:46, 28 December 2009 (UTC)
OK, I've made the proposal in various places, but let's do it here:
1. Delete redirects 1st dimension, 2nd dimension, 3rd dimension, First dimension, Second dimension, Third dimension
Weak, but plausible, as nominated by Prod. It should be noted that redirects may be nominated by prod.
2. Split 4th dimension // fourth dimension // 4-dimensional space into two unrelated articles:
1. 4th dimension // fourth dimension on the common usage (time, etc.) (base should probably be at fourth dimension, as it's primarily common usage, rather than mathematical usage)
2. 4-dimensional space on the spacial properties of 4-dimensional spaces.
3. Move, without redirect,
1. and then merge all common sections to n-dimensional space or perhaps n-dimensional geometry
Arthur Rubin (talk) 15:37, 28 December 2009 (UTC)
If there is general consensus for this here, we need to tag the articles to point to a centralised discussion. — Arthur Rubin (talk) 15:41, 28 December 2009 (UTC)
4 is making partially supported changes faster than I can propose correction. — Arthur Rubin (talk) 17:30, 28 December 2009 (UTC)
Aren't you supporting the moves in the first place? 4 = 2 + 2 04:20, 29 December 2009 (UTC)
I agree with the moves; not necessarily with deleting the redirects. At the very least fifth dimension needs to be a bluelink somewhere, if only so that there can be a hatnote, wherever it points, to The Fifth Dimension. When the Moon is in the seventh house.... --Trovatore (talk) 02:41, 29 December 2009 (UTC)

## Tensors on Wikipedia

Every so often, someone points out that our treatment of tensors is terrible. We currently have a bunch of badly written stubby articles: Tensor, Tensor (intrinsic definition), Intermediate treatment of tensors, and Classical treatment of tensors, not to mention other satellite articles like covariant transformation and covariance and contravariance of vectors in various states of shabbiness. Some well-meaning editors who otherwise lack any detailed knowledge of the subject seem to be interested in whipping our treatment of tensors into shape (please see my talk page for recent discussions with User:LokiClock). But I think the broader WP:WPM community should get involved (physicists are welcome too). Some of the recent edits have, in unskilled hands, been a step in the wrong direction. I don't have a clear picture of how things should look, but I know that the current status quo is pretty far from ideal, and I think there is at least consensus on this last sentiment.

I would hope that we could be able to get the current four main tensor articles down to two articles: Tensor for the full theory and Introduction to tensors for a gentler approach (on the model of the various "Introduction to X" articles that we have on Wikipedia). Comments and assistance are welcome. Best, Sławomir Biały (talk) 00:21, 29 December 2009 (UTC)

I'm not too keen on 'Introduction to' articles. I think the main article for topics should be written that way anyway for at least the first few sections and extra articles set up where the main article needs expanding. The classic treatment of tensors article doesn't strike me as anything like what I'd have expected there. Dmcq (talk) 10:10, 29 December 2009 (UTC)
Second on 'Introduction to' articles; every article should be an introduction to whatever the subject is. But User:Sławomir Biały has a point in that there are too many articles about basically the same thing. Unfortunately, we have a huge backlog of articles requiring attention, but Tensor seems like a worthwhile and basic subject that should be given a high priority.--RDBury (talk) 12:59, 29 December 2009 (UTC)
IMO, there should be only one tensor article. There is only one concept of tensor, a fact which is often obscured by physicists and mathematicians using completely different languages to discuss them. Since a wikipedia article should not rely on any understanding of any of those two languages this should not hamper writting a good wikipedia article about tensors. (As long as the editor recognized the difference in language and explain both.)
The tensor article will attract readers for diverse backgrounds, and as such should not rely on a detailed mathematical preknowledge. In particular, it should (at least for the first few section) not rely any knowledge of tensor products. Of course, it should contain the precise definition which will include tensor products, but this should be put into context for those that do not know what a tensor product is.
I don't have time right now to spearhead the considerable project of creating a single article. But I will definitely try to help out wherever I can if somebody else takes up the challenge.TimothyRias (talk) 12:37, 29 December 2009 (UTC)
I'm very encouraged by your post. I should clarify that I chiefly want a more unified treatment of tensors on Wikipedia. I would not be opposed to having just one article, but we currently have 4+ articles. A target of two might be easier to hit than a target of one. Or perhaps not. Sławomir Biały (talk) 13:00, 29 December 2009 (UTC)

I think that Tensor (intrinsic definition) looks like a fork of tensor product and that Classical treatment of tensors is almost content free. Merging those two with appropriate pages would be an easy start. The article tensor itself seems remarkably readable as a general introduction, so I am not sure why these other "introductions" are needed. — Carl (CBM · talk) 13:12, 29 December 2009 (UTC)

I've gone ahead and made the merger proposals. See Talk:Tensor. TimothyRias (talk) 15:26, 29 December 2009 (UTC)

That being said, it would be worth contacting the physics project and getting their opinions as well. — Carl (CBM · talk) 13:13, 29 December 2009 (UTC)

I just did a quick search and we have more like 20 articles with a subject beginning with 'Tensor'. We also have Tensor product which probably should have it's own article, and several Tensor product of X. Also Tensor field which I assume is a physics version of the subject. So I think the question is really how big a project to you want to do?--RDBury (talk) 13:21, 29 December 2009 (UTC)
For the moment I'm willing to live with satellites like Tensor field, and even the twins covariant transformation and covariance and contravariance of vectors (at least, since the latter has gotten into somewhat decent shape of late). The plethora of tensor product articles also aren't a huge concern for me at the moment, because these are by and large in better shape and (if you forgive my saying so) of less critical importance. Sławomir Biały (talk) 13:31, 29 December 2009 (UTC)
There a whole bunch of subjects related to tensors that merit their own article. Things like Tensor bundle (and related Tensor field), Tensor algebra, Tensor product, etc. are important of their own right and only loosely related to tensors themselves. We should not be aiming to merge those as well.TimothyRias (talk) 15:30, 29 December 2009 (UTC)

I believe it would be necessary to get the physics projects cooperation on this, otherwise the articles will just end up in the jumble in which they currently are. The first problem is that of the use of the word "tensor". Physicists (and mathematicians) use it to mean "tensor field" (and in fact, physicists mean something even stronger, as they normally consider the the behaviour of the tensor field under the orthogonal group, leading to the "tensor vs. pseudo-tensor" nomenclature). I don't think there's anything wrong with this use, but I believe it should be recognized as a "use", not as the actual name of the object. Thus, the first thing I would suggest would be to obtain a consensus within this project and with the physics project, on the title of articles. For this, it is logical to use the precise names of the different concepts, since they exist; however, these names are mathematical and physicists tend to resist such things as being too pedantic (though, frankly, I believe an encyclopedia should reach levels of pedantry higher than everyday scientific discourse). A "tensor" should be some element of the tensor algebra of a vector space, for example, whereas a varying family of tensors on a manifold should be called a "tensor field". Good luck. RobHar (talk) 16:50, 29 December 2009 (UTC)

There are basically two points here, and they both require respect. First is that Tensor should relate to numerous other articles by proper use of summary style; and doesn't. And secondly POV forks should not be present in the material (this is the point that there is just one concept of tensor). There are other points that help to explain where we are (e.g. that pedagogy in this area is a matter of taste or who you talk to, that Bourbaki is a demon or angel in imposing multilinear algebra as the setting, and the path-dependence of our ability to sort things out). These things are nothing much to do with writing encyclopedias, though, and people who mention them should have that explained, as ever politely. I know why Classical treatment of tensors is there in that form, and something definitely should be done about it, since "treatment" does not, based on what I have been saying, justify a separate topic. Charles Matthews (talk) 16:49, 29 December 2009 (UTC)

This notice is to advise interested editors that a Contributor copyright investigation has been opened which may impact this project. Such investigations are launched when contributors have been found to have placed copyrighted content on Wikipedia on multiple occasions. It may result in the deletion of images or text and possibly articles in accordance with Wikipedia:Copyright violations. The specific investigation which may impact this project is located here.

All contributors with no history of copyright problems are welcome to contribute to CCI clean up. There are instructions for participating on that page. Additional information may be requested from the user who placed this notice, at the process board talkpage, or from an active CCI clerk. Thank you. --Moonriddengirl (talk) 17:39, 19 December 2009 (UTC)

Just wanted to add that, even if you aren't interested in looking for copyright violations in these articles, cleaning up the ones identified could be very useful. They are marked accordingly at the CCI page. Articles that are blanked and listed at WP:CP, but not replaced by clean, are likely to be deleted, unfortunately. --Moonriddengirl (talk) 19:37, 19 December 2009 (UTC)
As I noted before (#Noncommutative measure and integration), this is an editor who created 20 articles in a short period of time, and these seem to now be target of your investigation. Imo, most of these (at least the math ones) are of dubious value even without the COPYVIO issue. But in hindsight it should have been a red flag for more serious issues. I'll go through and see if there are any math ones that should be saved, but I tend to be a deletionist so someone else should take a look as well.--RDBury (talk) 09:44, 20 December 2009 (UTC)
Here is a list of articles I found that seem meet notability criteria. There is incomplete since Google decided I was a bot trying to crash their server, will finish later after my time-out is over. There are a bunch of articles I didn't include because they aren't math related, and bunch more because notability was questionable. Nearly all the math topics had some sort of mention in research papers, but I was looking for non-trivial mention in a textbook. Even without possible copyvio problems, many of these should be looked at for style, context, questionable references. Most of them aren't subjects I know a lot about so I'm not going to attempt any repairs.
Hadamard variance, Steklov function, Quantum torus, Noncommutative quotients, Quantized calculus, Poincaré–Steklov operator, Fictitious domain method, Multiple-point constraint, Quantum affine algebra, Quantum time (Currently blanked), Quantum invariant (Currently blanked), Quantum double, Quantum algebra, Arithmetic variety, Quantum relativity, Axisymmetric spacetime, Canonical mapping, Concurrent relation, Qualitative calculus, Yang–Mills–Higgs equations, Vorticity tensor, Albert–Brauer–Hasse–Noether theorem, Cyclic algebra, Lambert's trinomial equation, Lambert of Auxerre, Quadratic algebra, Larmor's theorem, Lawson topology, Measure algebra, Open coloring axiom, Paneitz operator, Geodesic ball, Barta's theorem, Gregory M. Fikhtengol'ts, Codistribution, Cotensor, Matthias Flach, Laplace series, Scale property, Judith Q. Longyear
--RDBury (talk) 12:53, 20 December 2009 (UTC)
Here are some more: Model management, Spectral triple, Noncommutative plane, Graded C*-algebra, List of noncommutative topics in mathematics, Noncommutative integral, Noncommutative residue, Noncommutative Jordan algebra, Noncommutative fundamental theorem of algebra (probably should be Fundamental theorem of noncommutative algebra), Connes theorem, Noncommutative mathematics (This didn't actually turn up many hits but it's so broadly defined that maybe it's notable), Noncommutative Shilov boundary, Journal of Noncommutative Geometry (Need to check Wikipedia:Notability (academic journals)), Heinz Bauer, Differential invariant
I've now gone through all the articles he created, there might be more on the major edits list but those can always be reverted to pre-copyvio and probably not subject to deletion. I didn't really check the bio ones, just added them to the list since WP:BIO and WP:PROF are harder to check. Now I'm going to take a noncommutative shower and then go see noncommutative Avatar.--RDBury (talk) 17:44, 20 December 2009 (UTC)
while none of the articles are exactly "thrilling", for most of them I have difficulties to see any apparent signs of copyright violations or a need for deletion.--Kmhkmh (talk) 13:44, 20 December 2009 (UTC)
P.S.: Apparently consulting older versions of the author's discussion page provides further insight. Allegedly he might have copied sentences or small paragraphs from various websites rather than summarizing his cited references (in particular in early versions of the concerned articles). So other than completely rewriting the articles in general, one would need to look at earlier versions and run some bot/software for finding possible originals on the web to figure out whether there was an actual copyright problem needing correction.--Kmhkmh (talk) 14:02, 20 December 2009 (UTC)
I took care of Lawson topology. The referencing and notation there were both somewhat dubious. For example, it included a reference to Topology by T. Lawson, although the Lawson topology is named after J. Lawson and T. Lawson's book does not seem to mention the Lawson topology at all. So be careful in looking at the articles this person created. — Carl (CBM · talk) 13:43, 20 December 2009 (UTC)
I cleaned up a few articles yesterday and noticed two things that are helpful in looking for his copyvios.
1. He likes to cite his sources. Sometimes he tells you exactly where he stole from.
2. He likes to steal from the arXiv.
I've rewritten noncommutative algebraic geometry (the rewrite is at Talk:noncommutative algebraic geometry/Temp), and I checked all the math and physics articles between 221 and 240. Fortunately he doesn't seem to be subtle about his violations. Ozob (talk) 14:15, 20 December 2009 (UTC)
I've replaced the copyvio versions with your clean rewrite. Thank you and others of the project who are responding to this need. :) --Moonriddengirl (talk) 14:58, 20 December 2009 (UTC)

I had previously noticed that this editor's mathematical contributions were a bizarre mixture of sensible mathematics and useless nonsense, and I guess this is now explained: the good stuff was just copied. I recommend that all his mathematical edits should be deleted, because anything that is not a copyvio is likely to be wrong. In particular it would save time just to scrub all articles with no significant contributions from anyone else. I checked Connes theorem, which consisted entirely of a blatant copy from one of his sources; anything else like this can be speedy deleted using {{Db-g12}}. He does at least often give the site he has copied from. r.e.b. (talk) 22:08, 20 December 2009 (UTC)

I tend to agree, better to concentrate efforts on fixing the articles that should be kept (there are a few examples in the list above) than worry about the lost causes. It does seem that he put a lot of effort in these articles, so it seems a pity to just delete them, but if the material shouldn't be on Wikipedia then it needs to be removed. Maybe the deleted articles can be added to the list of requested articles so perhaps someone will write another version.--RDBury (talk) 07:48, 21 December 2009 (UTC)
I greatly appreciate the work your project is putting into this. :) r.e.b. at my talk page asks about presumptive deletion where this editor is the only major content contributor. This approach is certainly supported by policy at Wikipedia:Copyright violations. ("If contributors have been shown to have a history of extensive copyright violation, it may be assumed without further evidence that all of their major contributions are copyright violations, and they may be removed indiscriminately.") Some admins may choose to delete immediately. I would recommend blanking the article for listing at WP:CP as a courtesy to give any other interested contributors an opportunity to (a) help evaluate to verify that there is no infringement, or (b) rewrite the article before it is deleted. I have created a new template that can be placed on the talk page in such situations: {{subst:CCId}}. I would recommend placing the following on the article's face — {{subst:copyvio|url=see talk}} — and putting {{subst:CCId|name=Henry Delforn}} on the article's talk. --Moonriddengirl (talk) 18:11, 21 December 2009 (UTC)
I have a comment and a question. Comment: I disagree with the proposed remedy of summarily deleting the articles. Firstly, several topics are notable and already linked, and, therefore, having a stub is better than having nothing at all. Further, references and especially comments on talk pages aimed at improving the article will be irrevocably lost. Quantum affine algebra provides a good illustration to these concerns. Question: how is one supposed to go about fixing these articles? It seems to me that the placement of the template which simultaneously blanks the old text (including potential contributions by other editors) and gives a warning not to edit it would prevent one from effectively editing the articles. Does the new text need to be validated or approved by some "copyviolation committee"? Arcfrk (talk) 21:29, 25 December 2009 (UTC)
If you would like to rewrite the article from scratch, you may simply do so. The old copyright-violating revisions will then need to be deleted. You can contact me or any other admin and we can take care of that. — Carl (CBM · talk) 14:26, 30 December 2009 (UTC)

## Strange edit summaries by Golumbo

This is a new account making exclusively edits to math articles "reverting edits by a banned user". I looked at some and could not find what was being reverted and who that banned user might be. Can someone look if the edits make sense? Jmath666 (talk) 05:27, 28 December 2009 (UTC)

The banned user in question appears to be Afteread (talk · contribs), who was blocked by John Vandenberg (talk · contribs) as being a banned user (the block log doesn't say which banned user). However, Golumbo's reverts are also indiscriminately taking out other edits by other editors; e.g. his revert of Alexander Grothendieck to its pre-Afteread version also eliminated edits by Mavros-Belas (talk · contribs), 141.160.5.251 (talk · contribs), and Myasuda (talk · contribs). The situation could probably bear more careful inspection by math-literate editors. —David Eppstein (talk) 05:35, 28 December 2009 (UTC)
Sorry for the confusion or dismay. Here's the comment I made on Wikipedia_talk:WikiProject_Physics describing the situation: There appears to be a banned user creating multiple accounts serially, mostly editing BLP and physics articles. Their accounts may include Verbapple (talk · contribs), Afteread (talk · contribs), and Miles1228 (talk · contribs), all currently blocked. The edited articles include Bogdanov affair, Marcus du Sautoy, Edward Witten, Antony Garrett Lisi, An Exceptionally Simple Theory of Everything, Andrew Wiles, Elliot McGucken, Pythagorean triple, Lee Smolin, Leonard Susskind, Steven Weinberg, The Elegant Universe, Frank Adams, Jan Hendrik Schön, John C. Baez, Theory of everything, Peter Woit, Standard Model, Alexander Grothendieck, The Story of Maths, Kent Hovind, Luboš Motl, and several others. The banning policy encourages but does not require editors to enforce the ban:
"Anyone is free to revert any edits made in defiance of a ban. By banning a user, the community has decided that their edits are prima facie unwanted and may be reverted without any further reason. This does not mean that obviously helpful edits (such as fixing typos or undoing vandalism) must be reverted just because they were made by a banned user, but the presumption in ambiguous cases should be to revert. When reverting edits, care should be taken not to reinstate material that may be in violation of such core policies as neutrality, verifiability, and biographies of living persons. Users who reinstate edits made by a banned editor take complete responsibility for the content by so doing."
In the course of reverting some of this banned user's extensive edits, I may have reverted useful edits by them or others. Feel free to edit these back in as appropriate, as per the banning policy. I am not an admin, just another editor who took issue with this banned user. Golumbo (talk) 06:00, 28 December 2009 (UTC)
This is the typical approach to dealing with this particular banned user. Sorry I cant give more details publicly.
Definitely check the edits, and replay any subsequent edits which are good.
06:03, 28 December 2009 (UTC)

Thank your for clarification. However, if an editor wants to revert a past edit, whatever the reason, wouldn't it be up to that editor to do properly and actually revert the changes from that edit (which may have to be done manually and may take some work), rather than simply reset the article to just before the edit in question and lose all work since then? Jmath666 (talk) 08:04, 28 December 2009 (UTC)

Yea, it is preferable to carefully remove the edits by the banned user without also removing the edits by other users.
It gets messy when many other people have edited the same passages after the banned user; in cases like this recent sock, it is often simpler to roll right back.
I don't like doing that, but this person is a special case. 09:42, 28 December 2009 (UTC)
If you're not willing to share information on why this is needed, I think we're going to have to ask you to stop reverting in this fashion, at least on math articles. CRGreathouse (t | c) 19:18, 28 December 2009 (UTC)
Vandenberg has shared some information on the case with me privately, enough to convince me that the user in question should be kept as far from Wikipedia as possible. The number of edits in this case seems small enough that it shouldn't be too much work to figure out whether anything of value was lost and restore it. —David Eppstein (talk) 19:36, 28 December 2009 (UTC)
Fine, I withdraw my suggestion. Hopefully someone will keep track of this so we can restore edits when needed. CRGreathouse (t | c) 19:51, 28 December 2009 (UTC)

John Vandenberg (talk · contribs), could you explain why you believe Afteread (talk · contribs) is a banned user? Inspecting just a few of these articles (John C. Baez, Alexander Grothendieck, Bogdanov affair), all of Afteread's edits seem to me obviously helpful. Noamz (talk) 20:03, 28 December 2009 (UTC)

Wait, no, they don't. Sorry, I didn't notice all the changes Afteread made on the Alexander Grothendieck article -- there are a lot. Some of them look reasonable but many are questionable. Noamz (talk) 20:24, 28 December 2009 (UTC)
I had a look and it looks like someone is writing his less than notable contributions into a lot of places, you notice it more by looking at the stranger entries. Basically it looks like a very energetic ego tripper with some strange ideas who actually does know some maths and physics so its a bit sad they corrupt their contributions with this sort of stuff. Not sure why they don't mention the name I suspect is at the bottom of it all. Dmcq (talk) 23:39, 28 December 2009 (UTC)
Just had a look at more of the stuff and have concluded they are probably starting down the same kind of route as Archimedes Plutonium. Dmcq (talk) 23:53, 28 December 2009 (UTC)
ZOMG WP:CABAL. I have no idea what you guys are talking about, but the edits to Grothendieck were questionable speculation. Pcap ping 00:17, 29 December 2009 (UTC)
We avoid naming the person as a conscious decision to avoid harm, and because we don't want to give them cause to participate.
There are not many people for whom we have a scorched earth policy; this banned user is one of them.(offhand, I cant think of any others)
00:44, 29 December 2009 (UTC)
That's an awfully vague explanation for something that looks as non-transparent as this. I think you owe us better. --Trovatore (talk) 01:49, 29 December 2009 (UTC)
Just a cowardly remark: I would point out that the edits of this person precede User:Afteread, and appear to be traceable to the real life identity. I'm comfortable that Checkuser confirmed this, that blanket reversal is a required and appropriate approach, and also agree that a number of good edits are temporarily moved down the "history" list (until it's cleaned-up, which it will). For supporting the ban from an admin side, I would suggest not to point to some "inner circle"-style authority for making "the right" decisions, but simply state the abuse pattern: A large number of Wikipedia user names with a huge number of "minor" marked edits (that are mostly of high quality) attempt to obscure individual edits here and there, that range from sneakily "slanting" (primarily in the physics community) to outright suppression attempts (primarily in Christian young-Earth creationism related articles). -- Signed by another coward. BeforeAfteread (talk) 02:09, 29 December 2009 (UTC)
I don't see why it's our problem if his edits are traceable to real-life identity. Let them be traceable. Frankly there is far too much bending over backwards to prevent people's identities from coming out, when those people give clues all over the place as to who they are. --Trovatore (talk) 02:33, 29 December 2009 (UTC)
The issue isn't the real-life identity of the user being reverted. Paul August 03:31, 29 December 2009 (UTC)
• John Vandenberg is correct. Please assist him by fixing any collateral damage due to reverts. Thank you. Jehochman Brrr 02:10, 29 December 2009 (UTC)
The situation here is truly a special circumstance. There are very sound and considered reasons behind these reverts and the circumspection with which the reverts are being carried out. Paul August 03:27, 29 December 2009 (UTC)

I think I've figured it out.

 This user is a suspected sock puppet of Cthulhu. Revert all edits of this user immediately. Account information: block log – current autoblocks – edits – logs – abuse log

CRGreathouse (t | c) 05:02, 29 December 2009 (UTC)

LOL BeforeAfteread (talk) 14:27, 29 December 2009 (UTC)

I am here to say that I agree with the actions that John and Paul and others have taken in this matter and to ask for forbearance if less explanation than usual is offered. That's not entirely satisfactory but the less discussion of this, the better. ++Lar: t/c 05:25, 29 December 2009 (UTC)

You guys are doing good work. User:Golumbo's list above (and his/her contributions) are a good reference point for the large amount of edits affected. The abuse of Wikipedia is systematic, and the revert is justified from the nature of these edits alone. Nothing else needs to be said. While it is regrettable to revert many edits of high quality, from a knowledgeable editor, the attempt to slant articles in a way that is labor intensive for others to follow-up and dispute, cannot be accepted. If someone believes that an article is incorrectly representing its content, then he/she can make a point with far fewer edits, and discuss on the talk page. The burden of justifying a change in tone on a Wikipedia article should lay with the editor who brings forward that change, not with all others who'll have to do the clean-up. BeforeAfteread (talk) 14:27, 29 December 2009 (UTC)
I have been sent to this discussion from John Vandenberg following the tersely-justified deletion of a page I had in my userspace, which has something to do with this case. Can someone explain clearly what is going on? I mean, we don't have a scorched earth policy even for Daniel Brandt. What is going on here? No matter how much AGF I can put in my tea, it is unacceptable such a full secrecy between admins and the community. --Cyclopiatalk 14:32, 29 December 2009 (UTC)
Some of us may have overreacted, our bad; we're human, too. Nobody is "banned", there is no "scortched earth", and every editor's contribution is a gift to Wikipedia, whatever the takeaway. -- I stand behind my support for the blanket revert, due to the vast scope of the edits, impact on the clean-up crew, and intent. BeforeAfteread (talk) 14:43, 29 December 2009 (UTC)
I don't know anything of Golumbo, the reverts, etc. and I have no opinion on that. What I have opinion on, instead, is the secrecy that is going on in this case. Unless we're protecting someone's identity for outing reasons (but above is mentioned that it is not the reason), there should be no secrets on WP. I even was refused any explanation by email. This is not acceptable. At least, a reason for all this secrecy has to be given. "We know better" is not a good reason: it only shows contempt for the community. --Cyclopiatalk 15:05, 29 December 2009 (UTC)
Support that. If there is somewhere this is discussed I'd have thought that would be a reasonable place to direct people to even if the banned user might unfortunately follow the links back to here. Dmcq (talk) 15:12, 29 December 2009 (UTC)
The banned user only ever needs to click "What links here" in the toolbox on the left on their banned accounts user pages to see where they're being discussed. And the secrecy only seems to be prolonging the discussion. Ben (talk) 15:19, 29 December 2009 (UTC)

Just to chime in as a relatively junior WP:Math contributor but also as a wiki functionary who has a little more info about these edits that this is a rare case that requires both quick and decisive action with a minimum of "on-wiki noise". If there is ever a time that we should trust that ArbCom is acting in the best interests of the project and each and every one of its members, this is it. -- Avi (talk) 15:25, 29 December 2009 (UTC)

I don't think the issue is about trust so much as it is about respect. I trust that the ArbCom has made the right decision in banning the editor, but as Cyclopia noted, there is a feeling of contempt for the community in the way this is playing out. That userfied pages are now being deleted only amplifies that feeling. Ben (talk) 15:40, 29 December 2009 (UTC)
People who ask reasonably, and privately, once... get answered to the best of the ability of the person they ask, keeping in mind what can and can't be said. Please remember, that those of us handling it have the trust of the community to handle sensitive matters (everyone involved holds at least CU here, if not more permissions, and most are ArbCom, ex ArbCom, stewards, oversighters and the like). That means trusting us when we say that not everything can be discussed, and not worrying at the matter repeatedly. That defeats the purpose of not discussing it in the first place. Please review WP:RBI and think about what that page means/implies if what you are dealing with is one of the worst editors ever. Which we are.
People who keep worrying at this, over and over, and who get increasingly shrill about their "rights" being trampled, or demanding that they be given text back, or saying we're all exactly equal and they are entitled to know every detail of every private matter... these people get increasingly short shrift. If they keep up to the point of being disruptive, they may be sanctioned. It has happened before. I would not like to see it happen again but it could. ++Lar: t/c 15:53, 29 December 2009 (UTC)
Threats. Nice. --Cyclopiatalk 15:57, 29 December 2009 (UTC)
Knowing what Lar knows, I think he just lost patience with the discussion here. I don't think sanctions or the threat of sanctions are necessary or helpful here. And I'm sure that Lar agrees. This is really a very unfortunate situation. Maybe we can all count to ten? Paul August 16:24, 29 December 2009 (UTC)
Nod. @Cyclopia: If you're reading what I wrote as a threat, I'm really sorry. it's not intended as a threat at all. Just a warning. This is a very serious matter. People have been sanctioned before and I'd rather not see it happen again. As I said... asking privately is fine but when those given extra permissions and extra trust say "please trust us"... the thing to do is trust them. All of ArbCom has awareness of this matter (in the larger context) and what we do to handle it is being scrutinized, closely, so trusting us is the appropriate and polite thing to do, instead of worrying at it. Will you do us that courtesy? ++Lar: t/c 16:29, 29 December 2009 (UTC)
Lar explained me the bare minimum necessary to understand what is at stake. As such, yes, issue solved, and sorry for the hassle. It would have been simpler if the seriousness of situation was clear for the start, but I'd say issue resolved. --Cyclopiatalk 16:44, 29 December 2009 (UTC)
Thanks. Paul August 17:44, 29 December 2009 (UTC)
Afteread (talk · contribs) and his odd edits had already been reported 2 weeks ago on WP:FTN here. Mathsci (talk) 17:05, 29 December 2009 (UTC)
@Avi. As much as I respect John Vandenberg he's no longer part of ArbCom, and did not claim to act under their mandate either. Pcap ping 02:28, 30 December 2009 (UTC)
He is acting on behalf of ArbCom, and he could have noted as such, although he didn't :) -- Avi (talk) 05:33, 30 December 2009 (UTC)
I believe that there are members of Arbcom who responded here, and if not, please trust me that from the discussions I have been privy to, they are pretty much all in agreement. -- Avi (talk) 05:37, 30 December 2009 (UTC)

People, the average case and the worst case are not the same, or anything like, in these matters. One feature of the "worst case" is that even defining why it is not just a "bad case" can be very problematic. I have no idea at all about the details of this matter, but if the ArbCom is in the loop, that's good enough for me. Charles Matthews (talk) 17:03, 29 December 2009 (UTC)

It is not good enough for me. Nobody here has pointed to any discussion or decision on the part of ArbCom. I am not in the loop, not connected to all the right people, not in the know; I cannot tell whether this editor is being condemned because he is one of the worst editors ever or because a cabal has a personal vendetta against him. I trust many of the people involved in this discussion, so I would like to believe that this editor is one of the worst ever. But nobody has provided evidence; we are asked to believe not in the truth but in interpersonal politics. I am sorely tempted to call these reversions blatant vandalism and to re-revert myself. I would, however, switch my position immediately if only someone could prove that Afteread is subject to legitimate sanction. Ozob (talk) 17:59, 29 December 2009 (UTC)
Unfortunately providing public "proof" may do more harm than good. Paul August 18:21, 29 December 2009 (UTC)
Ozob, I understand you completely, per my comments above. But it turns out it is right, even if maybe how admins are handling the matter with users is suboptimal. Ask some admin to email you in private, like I did and (not without some difficulty) obtained. Let's say that there are very serious real life concerns. --Cyclopiatalk 18:23, 29 December 2009 (UTC)
@Charles: I suspected as much from the edit history, but I'm really clueless why writing "sockpuppet of someone banned in BA case" is beyond the pale. Pcap ping 02:35, 30 December 2009 (UTC)
By the way, I also clueless why an WP:AE report (now archived) that seriously concerns NPOV in an article sees little commentary and practically no action, whereas this is scorched earth territory. Pcap ping 02:41, 30 December 2009 (UTC)
Someone more familiar with the details emailed me privately. Apparently this user is unusual, and there is a good need for discretion, yes, even to the point of making this "scorched earth territory". But I still object to the secrecy around this case. I still do not see why it is unacceptable to say, "He is a sock of the banned user So-and-so" or at least to make a public statement as to why identifying him is inadvisable. As I wrote in an email,
Maybe I can present my concern from a different perspective. In Britain at one time they had a court called the Star Chamber; you can look it up on WP, it has a decent article. The proceedings of the Star Chamber were entirely secret. As you might expect, this eventually lead to abuses and to the abolition of the Star Chamber. One of the reactions to the Star Chamber was the English and American legal systems' principle that evidence and proceedings should generally be public. Exceptions are very rare and contentious (think of Guantanamo and all of the scrutiny which military tribunals there underwent). I think that principle is extremely valuable, and I am very reluctant to endorse any exceptions to it. I think it is a valuable principle for WP also. A system such as WP's which relies so heavily on consensus cannot function without wide distribution of information.
Of course, as I went on to note, I don't like to get involved in user conduct disputes. Furthermore, I suspect that in this case, the details are sensitive enough that the general public, including me, should not know all of them. So I'm left uneasy and unsatisfied. I have learned, again by email, that there are several of us who feel this way.
I do have one suggestion for those who have more detailed knowledge of the situation. I would not be surprised if some day there is another thread similar to this one. It might be good if you could write a one sentence description along the lines of, "We cannot discuss this situation because of ..." I think that would help relax those of us who don't know the details. Ozob (talk) 05:19, 30 December 2009 (UTC)

I have been sent the name of this editor via email (I just had to ask for it). I have found some of the details in the internets. Turns out that I had previously read about this editor in the internets, and I was adequately impressed by his... uh... varied accomplishments and his .... uh.... actions in.... uh....... you know what, forget it, this just can't be summarized without revealing private stuff. I understand why the details are not being released, and I fully endorse the nuking-from-orbit approach to this matter. --Enric Naval (talk) 07:05, 30 December 2009 (UTC)

If we strip out all the stuff here that we maybe shouldn't have been told about from starters, all those details that cannot be revealed (and honestly that I don't care to know, either), and only look at the edits to hundreds of pages that John and others are cleaning up now, then one can recognize the sophisticated and deliberate abuse pattern. The only "trust" (if any) that one may want to bring forward IMHO is towards chechusers for validating the identity behind the dozens of sock puppets and IP addresses. And even then, even if you are suspicious of checkuser privileges (which is a good thing! question authority and power!), John is marking his edit summary clearly by stating "banned user", which makes everything that's going on to the content in Wikipedia fully transparent. And that's all I'm concerned about, for Wikipedia, and by looking at the content alone I am satisfied with the actions. There is no secrecy or hiding of content. As for the rest, it's good drama - wow. BeforeAfteread (talk) 16:25, 30 December 2009 (UTC)

My actions can be reviewed by looking at my contribs from 2009-12-28 09:10 (UTC) until today (and probably inc. tomorrow).
Here is a link of the first 500 edits that are relevant[2].
If you see some good content being lost in this process(and only if you know the topic well), please don't re-instate the reverted content; instead, rewrite it in your own words.
00:03, 31 December 2009 (UTC)

Do you guys think he qualifies for a bio article here? Based on the current contents of his bio, I'm in doubt. There was a discussion in 2005, way before we had any standards. The argument that he invented Unlambda is exceedingly weak; I could barely find secondary references to add to that article— it's not a well-known language by any stretch. Pcap ping 08:31, 30 December 2009 (UTC)

Based on what's in the article now no. The best thing might be to put it up at AfD: it may get deleted but that also often leads to interested editors taking the time to find references to support the subject's notability, improving the article in the process. --JohnBlackburne (talk) 10:05, 30 December 2009 (UTC)
Done so. Thanks for the advice. Pcap ping 12:17, 30 December 2009 (UTC)
In general, it's impolite to use AFD as a way to force other people to look up references for you. But in this case, the AFD seems to be appropriate, based on Madore's CV. The spirit of WP:PROF is that we want to cover only the people who are more notable than the average successful academic. It appears that Madore is doing well, but has not yet become more notable than average. In general, if someone who has only had their degree for a few years passes WP:PROF, they will be obviously notable (e.g. Ben J. Green). — Carl (CBM · talk) 13:56, 30 December 2009 (UTC)

## Adding an example to Weak convergence (Hilbert space)

I'd like to add an example to this page to help bright the concept to life a bit, but I want to collaborate with someone who know more than me about this before making any major edits. futurebird (talk) 02:49, 31 December 2009 (UTC)

## Tool for maths ratings

Apropos to previous discussions about articles whose {{maths rating}} data is incomplete, I have two tools to make it easier to manually fill in the missing information.

1. http://toolserver.org/~cbm/cgi-bin/mathsrating.fcgi – this wraps the Wikipedia interface inside a frame, and randomly loads an article that needs to have its maths rating template fixed. You can edit as usual within the frame. Click 'reload' at the top to either skip the present article or move to the next one. The count at the top is for all articles in any of these categories:
2. User:CBM/ratemath.js – this adds a link to the user interface at the top of an article, allowing you to set the maths rating template without having to load the talk page or type any code by hand. Occasionally, it may balk at removing the old template, in which case you have to do it by hand in the usual way. To use this tool, you need to put importScript('User:CBM/ratemath.js'); in your monobook.js or vector.js (depending on which skin you use) and then clear your cache. When using the tool, I recommend always waiting for the talk page to be loaded, to double-check the output. This is not intended for automated use in any way.

If you have time and are interested, doing just a few articles a day would be a great help to the project. There are about 1500 articles that need attention. — Carl (CBM · talk) 18:00, 29 December 2009 (UTC)

Very useful tools. Thanks, Carl! I have a question about each of them.
1. For the first one, is it possible to have the category searched be determined by the user? For instance, I would like to assess only those math articles that I understand, so for instance I might only want articles in Category:Graph theory.
2. For the second tool, can it be programmed so that when you click on "rate math", it picks up the current rating and displays it by default? For example if someone has already assessed the field, but not the priority, can it show the pre-assessed field, and load in some default values for the rest. I guess this might be hard to program, but it would be neat if that were possible.
Robin (talk) 20:10, 29 December 2009 (UTC)
Those would not be as easy as it seems. The problem with categories is that our category tree is very deep, so the system would have to do a recursive scan of the category tree somehow. The javascript tool is something I hacked together a while back despite not knowing any javascript. I don't think I will be able to improve them much, although I agree that the improvements would be nice. — Carl (CBM · talk) 21:00, 29 December 2009 (UTC)
I understand. I have a makeshift solution for both problems, so I'm satisfied. For the first, User_talk:GregU/randomlink.js randomly loads a page linked to on a given page. It also implements a link depth of 4 links, so one could start at a Category like Graph theory, and the random link could take you to a page like Graph theory>Graph coloring>Perfect graphs>Chordal graph. That's good enough for me. For the second problem, I installed the project banners script -- User:Pyrospirit/metadata/projectbanners.js. This gives a quick overview of the project banners on the article page itself, saving me a click on the "talk" button and back. --Robin (talk) 21:56, 29 December 2009 (UTC)

Not sure if this has been covered before, but I think even putting the maths rating tag in without parameters has some value. Specifically the bot that updates the article alert page only recognizes articles which have the tag.--RDBury (talk) 12:08, 30 December 2009 (UTC)

We don't really use that system; we use Wikipedia:WikiProject_Mathematics/Current_activity which does not rely in any way on talk page tags and thus covers a more complete set of articles than article alerts. This is one reason why we have always rejected letting a bot go through and add a template to math-related articles, because the value in the tags comes entirely from the assessment information. — Carl (CBM · talk) 13:30, 30 December 2009 (UTC)
There's also a counter-argument, that if we let a bot go through all the math articles and tag them with "maths rating", then interested editors who wish to assess them can do so very easily, by just going through the list of unassessed articles (in their field of expertise). Right now it's really hard for an editor to find math articles in field X which aren't tagged by "maths rating". --Robin (talk) 16:04, 30 December 2009 (UTC)
The current activity page doesn't include everything (yes, I monitor that as well). For example the articles with copyright problems doesn't show on the current activity and we've had quite a bit of activiity there recently.--RDBury (talk) 11:52, 31 December 2009 (UTC)
Re RobinK: there are about 16,000 articles that are on the list of mathematics articles but not tagged with {{maths rating}}. Experience says that a backlog that big will simply sit forever. That is, if a bot tagged 16,000 articles, we do not have the volunteer time to go behind it and fill in the missing information. We already have a backlog of 1,500 articles that I am hoping to work through over a period of several months.
However, I can definitely make a tool to list mathematics articles in a particular field that are not tagged. — Carl (CBM · talk) 12:59, 31 December 2009 (UTC)

Re RobinK: I whipped up two tools for you this morning:

• nomathsratingcat - browse the category tree looking for articles without the maths ratings template
• mathsratingcat - browse the categorytree looking for articles with incomplete maths ratings

All the numbers reported are from the live toolserver database. There is often a small amount of lag between the toolserver and the production database used for the actual site, but changes should be reflected very quickly overall.

None of the numbers shown is recursive. That means that the number only refers to articles that are directly in the corresponding category.

I realize these tools are not yet ideal, but I wanted to get something working right away. I'm happy to take feedback and improve the tools if possible. These are really just a proof of concept. — Carl (CBM · talk) 14:07, 31 December 2009 (UTC)

P.S. I do think these two tools can be combined into one tool, once I am sure there are no performance issues. — Carl (CBM · talk) 14:40, 31 December 2009 (UTC)

They're great tools, thanks! I used them for a while, and I see no problems. I've taken care of most of the incompletely rated articles in Discrete mathematics and Theoretical computer science. Can't think of any improvements, except adding recursive scanning, but seems fine even without recursion. Any way for me to know how many articles are left? Like where did you get the number 16,000 from? It's not necessary to know this, but it adds to the feel-good factor if you see that you've brought down the number from 16,000 to 15,900 or something. --Robin (talk) 16:01, 31 December 2009 (UTC)
On an unrelated note, how does the tool "Find articles without maths ratings by category" work? Does it intersect some categories? (For example, when I search in category complexity classes [3], I get exponential time but not pseudo-polynomial time, even though both are in exactly the same categories and have no WikiProject templates on their talk page.) --Robin (talk) 19:14, 31 December 2009 (UTC)
The tool only considers articles that are listed on (subpages of) List of mathematics articles. I don't know why exponential time is listed there but not pseudo-polynomial time. EXP was added back in 2005, probably because it had Category:Exponentials at the time. I don't know the exact algorithm that the bot uses to update the list of math articles (in particular, I don't know the criteria for removal). Oleg Alexandrov would know more details.
To get 16,000, I used the count of 23,000 from [[Wikipedia:WikiProject Mathematics/Count] and the count of 7,000 at Wikipedia:WikiProject_Mathematics/Wikipedia_1.0. I could certainly add an overall count of articles with no maths rating tag, although it will be very large. I think it should be efficient to generate.
Recursive scanning is somewhat more work to implement. But, because there can be a lot of semantic drift as you get deeper down the category tree, I think it would make more sense to make a better interface for navigating the tree (maybe by adding a history so you can see how you got to the location you are currently at). A limiting factor is my development time; my first WP priority right now is finishing the new WP 1.0 bot, so I can't spend too long developing a new assessment tool until that is done. The tools I whipped up yesterday could be written quickly because they didn't involve too much complexity. If anyone else is interested in working on code for an assessment tool, I can help walk them through the process of getting a toolserver account. — Carl (CBM · talk) 13:04, 1 January 2010 (UTC)
OK, thanks. I think the tool is pretty usable as it is. I managed to assess quite a few articles yesterday. --Robin (talk) 15:33, 1 January 2010 (UTC)

## Pierre Deligne

Tiresome POV pushing by someone concerned to denigrate the achievement of Deligne in completing the proof of the Weil conjectures. Please help revert. Charles Matthews (talk) 10:25, 31 December 2009 (UTC)

I have reverted his/her most recent revert. However, if he/she continues to be disruptive, WP:3RR applies, and he/she could be blocked. This should be considered should he/she revert once more. --PST 10:40, 31 December 2009 (UTC)
There's a discussion going on here. (He edited Charle's user page, rather than his talk page, so I moved the reply from there). Pcap ping 10:44, 31 December 2009 (UTC)
He already broke 3RR, if he continues, just report him with these diffs: [4] [5] [6] [7] [8] . I need to go offline soon. Pcap ping 10:51, 31 December 2009 (UTC)
I have reported him. The user has reverted 5 times, and has only responded once to our requests (and not waited for a reply before reverting again). This exceeds the limit for WP:3RR by at least one edit. Thanks for the diffs; I have used them. --PST 11:57, 31 December 2009 (UTC)
He replied on your user page as well, and then he reverted himself. I think he's trying to communicate in good faith, he's just confused about the multitude of pages here. I did my best to consolidate the discussion on his talk page. Pcap ping 13:02, 31 December 2009 (UTC)
I think that you may be right, and hopefully the block does not discourage him from editing Wikipedia. However, it did not seem that pure communication could prevent him from reverting; I think that he was unfamiliar with WP:3RR. As a consequence, I have apologized to him on his userpage; he may not have deserved the block, but Wiki rules do apply. Perhaps my apology may remove heat from the matter. --PST 13:23, 31 December 2009 (UTC)

## Comment requested at Talk:Legendre polynomials and Talk:Associated Legendre function

Could someone please comment on the suitability (or unsuitability as the case may be) of including detailed proofs of the Rodrigues formula in the articles Legendre polynomial and Associated Legendre polynomial, as was recently done in these edits, respectively: [9], [10]. I am sorely tempted to remove both proofs as essentially trivial calculations from the Leibniz rule for repeated differentiation. This seems to be the kind of proof that our project has decided against including. I am not opposed to adding something like this which delivers the main idea behind the proof without giving step-by-step details. I have tried to solicit some input on Talk:Legendre polynomials, but it has been a few days and so for it has not elicited any discussion. On the contrary, the new proof has just now been added to Associated Legendre function. I would like an outside opinion on what to do before proceeding with my own preference: remove the added sections, and replace them with a short summary of the proof. I would do this myself, but I have had other rather abrasive interactions with User:Stamcose, and an outside opinion might help to defuse the situation. Sławomir Biały (talk) 17:24, 31 December 2009 (UTC)

Yes, a dull proof to write out in detail, OK as a thumbnail "applying the Leibniz formula to ... ". Charles Matthews (talk) 14:42, 1 January 2010 (UTC)
What about replacing the proof with a short summary, and then creating new pages (Legendre function/Proofs) which gives the proof in full detail? Ulner (talk) 15:00, 1 January 2010 (UTC)
The '/Proofs' idea is against WP policy; the articles namespace does not allow subpages. There are no references given so it might be better to check to see if this is OR before deciding other issues. OR proofs can be valid but there might be simpler ones available in the literature.--RDBury (talk) 15:17, 1 January 2010 (UTC)
It's pretty obviously not OR, but suffers from the opposite problem: it is painfully routine. Sławomir Biały (talk) 15:34, 1 January 2010 (UTC)
Why can't something be OR and routine? If it's just plugging in the definitions and turning the crank then all the more likely that it is OR. If it's proved as a special case of a general theorem or using some clever trick then the more likely that it's from a published source. That's been my experience anyway.--RDBury (talk) 15:54, 1 January 2010 (UTC)
I agree that subpages are currently disallowed, and propose insread to use 'Legendre function (Proofs)' as a separate page instead. The following pages should be moved accordingly: Christoffel symbols/Proofs, Approximation theory/Proofs, Vector Laplacian/Proofs, Boy's surface/Proofs. Ulner (talk) 16:28, 1 January 2010 (UTC)
You're basically proposing subpages with parentheses instead of a slash. The point of doing the subpages was to get around needing to have proof pages satisfy WP:GNG and changing the name won't solve that. This is a complex issue and the previous consensus was that these articles need to be handled on a case by case basis. I'm currently working on this (anyone who wants to help is more than welcome) and you can find the current status at User:RDBury/Proofs articles for cleanup--RDBury (talk) 18:40, 1 January 2010 (UTC)

If there is nothing more to Legendre function (Proofs) than such proofs that were routine by about 1850, I would propose it for deletion. Wikipedia doesn't include pages on miscellaneous calculus exercises, even though you could undoubtedly reference such pages to multiple standard texts. This all falls under "Wikipedia is not a collection of miscellaneous information", really. The topic of a page has to have independent status as something adding to the encyclopedia's coverage. Charles Matthews (talk) 18:55, 1 January 2010 (UTC)

I agree with the arguments given here; new subpages should in this case not be created. Ulner (talk) 18:58, 1 January 2010 (UTC)
After rethinking, I suggest to follow Sławomir Biały's suggestion: rewrite the proof to only provide a short summary of the argument (with a reference to (preferably) some textbook where the complete proof can be found or (if not possible to find textbook/research article) to some wikibook). Ulner (talk) 19:02, 1 January 2010 (UTC)

## FYI, links in Proofs talk page

I added links to threads from this page to the Wikipedia talk:WikiProject Mathematics/Proofs since it seems that much of the relevant discussion takes place here (previous thread included). There are probably more than I have listed, but it's a start. Look in the archives box.--RDBury (talk) 22:19, 1 January 2010 (UTC)

## Recognized Content subpage

There is a new recognized content bot that the physics project has signed up for, see Wikipedia:WikiProject Physics/Recognized content. Any thoughts on signing WPM up as well?--RDBury (talk) 12:42, 31 December 2009 (UTC)

We have a list directly on WP:WPM (and not nearly as many articles). Still, if the bot just updates a subpage of WPM and you're interested in it, I can't see any reason not to sign up for the bot. — Carl (CBM · talk) 12:53, 31 December 2009 (UTC)
I can't imagine anyone objecting to having that subpage, so I've gone ahead and created it at Wikipedia:WikiProject_Mathematics/Recognized_content. Of course it can be moved/renamed if people prefer a different name/location. I've used the same parameters as the physics page, but someone can double check to make sure I haven't missed anything. I haven't added "features pictures" and "featured portals"; I'm not sure if we have any of those on WPM. --Robin (talk) 18:10, 31 December 2009 (UTC)
It looks like it populated ok and I added a link from the project page. I think the main advantage is that it's populated automatically. On the other hand some of the articles under FYI are a bit questionable so maybe it's better to have a human to filter them.--RDBury (talk) 13:56, 1 January 2010 (UTC)
It might even be a good idea to transclude the recognized content page on the main page, like they have on WikiProject Physics, for instance. I think the bot formats the page quite well, so it would look pretty neat on the main project page. The only problem right now is that the bot makes all the heading level 2 headings, which wouldn't work on the main page, since they should be level 3 headings, but I think the bot's creator is working on that problem. Assuming that problem does get fixed, do people want to have this page transcluded on the main page? --Robin (talk) 15:47, 1 January 2010 (UTC)
Wow that is really cool. If I recall correctly, we do indeed have a few featured pictures. Is it possible to add them to the list? Cheers, Ben (talk) 14:25, 1 January 2010 (UTC)
Doesn't seem to be one of the parameters but I'll request it.--RDBury (talk) 15:21, 1 January 2010 (UTC)
I think the bot can handle featured pictures too. I'll add it to the page so that they'll get added on the next round of updates. --Robin (talk) 15:35, 1 January 2010 (UTC)
I added the features picture option, but the bot didn't add any when it updated the page. I think the reason is that featured pictures are not tagged with the "maths rating" template, whereas the bot's algorithm looks for the this template. --Robin (talk) 15:54, 1 January 2010 (UTC)
The parameter is there, I missed it earlier, so most likely you're right in that the maths rating tags need to be added. See User:JL-Bot/Project content/documentation for the documentation.--RDBury (talk) 18:51, 1 January 2010 (UTC)

(outdent) I added the tag for ten featured images so hopefully they will show up in the next refresh.--RDBury (talk) 19:09, 1 January 2010 (UTC)

The pictures are there in a nice gallery.--RDBury (talk) 12:48, 2 January 2010 (UTC)
Looks good here. Thanks for that RDBury. Ben (talk) 13:58, 2 January 2010 (UTC)

## User:Indefiniteintegral

This editor has created three math articles, Leibniz function, Leibniz differential, and Fermat differentiation. Two of these are currently PRODed and the third is dubious at best. All three use the same calculus textbooks as references. My question is, is it a coincidence that these three subjects appear in the same two calculus books and nowhere else or is this person creating hoax articles? The non-math articles this editor created are also dubious.--RDBury (talk) 15:26, 2 January 2010 (UTC)

These three subjects do not even seem to appear in the cited "Advanced Calculus Demystified" source. I am unable to check the Abbott and Neill source. I support the prods, as well as closer scrutiny of the editor's other contributions. Sławomir Biały (talk) 16:10, 2 January 2010 (UTC)
Thanks, just wanted to make sure it wasn't just me. This user turns out to be a sockpuppet of a banned user; I did a quick check on articles created by other aliases but not other articles created turned up. Some review of major edits might be worth while.--RDBury (talk) 18:44, 2 January 2010 (UTC)

## De Moivre's formula

An editor keeps trying to say the De Moivre's formula‎‎ is true for non-integer powers and stick in their own proof. The problem is they have a copy of a Schaum's outline backing this error though it says the proof is outside the scope of this book. Any idea how to explain things to them better?, I put in a bit into the article showing why it was wrong for non-integer powers but it obviously doesn't convince them. Dmcq (talk) 19:04, 2 January 2010 (UTC)

The problem may be that there is always a value of the non-integer power for which de Moivre's theorem is true. Septentrionalis PMAnderson 04:28, 3 January 2010 (UTC)
I'll see if I can't put a link to the generalization section in the bit only being true for integers or somewhere else near the top. Dmcq (talk) 07:09, 3 January 2010 (UTC)

## Discussion on Trott curve

There's a slow but ongoing discussion on Talk:Trott curve regarding whether the subject is sufficiently notable for a standalone article, should be moved to a more general article concerning the (much older and more famous) result that quartics have 28 bitangents rather than this specific quadric, should be merged with bitangent, etc. Please participate. —David Eppstein (talk) 19:59, 3 January 2010 (UTC)

## Saturated model

There was a minor kerfuffle, more or less resolved now, at saturated model, where an editor put {{technical}} and {{context}} tags on the article. It is certainly true that the article could stand better contextualization (Hans, maybe you'd like to take a crack at it?).

But that's not the main point — as it turns out the editor thought the article was about something completely different, a concept from something called structural equation modeling, about which I know nothing. Also when I look at "what links here" from saturated model, one of the links is from friction, which is certainly not referring to the model-theory concept. Whether it's referring to the SEM concept, or to still a third one, I don't know.

Anyway the point is that this/these concept(s) could probably use a writeup. Does anyone know anything about it/them? --Trovatore (talk) 23:59, 3 January 2010 (UTC)

The one from friction appears to be a third concept. I could probably write a stub on the statistical concept. Michael Hardy (talk) 02:47, 4 January 2010 (UTC)
Well, this kind of kerfuffles keep us sharp. Anyway in the meantime I have found (I think) a basic definition of what a saturated path model is: A path model having an equal number of (non-observed) parameters as it has observed variables [needs some extra tweaking]. In this case the model has zero degrees of freedom (df=0). Every covariance matrix (of the right size for the model) can then be reproduced using the model and all standardized residual covariances equal zero. I hope I got this right, my teacher didn't make it all too clear, I had to reconstruct it from disjointed fragments. It'll need better phrasing and stuff, but still.
I think it would also be a good idea to make at least a stub describing a path model. --JorisvS (talk) 11:35, 4 January 2010 (UTC)

## All-ones vector

There is a new article All-ones vector with no references or evidence of notability; at first glance it appears to be OR. The term is used in the article Boolean algebras canonically defined without definition, but perhaps it was assumed to be self-explanatory. It seems to me if the term is self explanatory then the new article should be deleted, if not then the definition should be in the Boolean algebras article and the new article should be a redirect. In either case, a new article is not justified. I'm not an expert in Boolean algebras however, so I don't think I'm qualified to make the call, but it would be helpful if someone who has some expertise in the area could either add the definition to the Boolean algebras articles or indicate that it's not needed. Also, 'Boolean algebras canonically defined' is a very strange name for an article and probably violates naming criteria, any chance that could be resolved as well?--RDBury (talk) 13:01, 30 December 2009 (UTC)

I prodded it as (mathematical) WP:DICTDEF. Pcap ping 13:13, 30 December 2009 (UTC)
It's related to this WP:RD/MA#The all-ones vector, and how to notate it. The editor who asked the question seems to have taken the unusual step of turning that unresolved query with little interest in it into an article. So yes, un-notable OR by any reasonable measure. --JohnBlackburne (talk) 13:28, 30 December 2009 (UTC)
Not sure if the query was turned into an article or the query was to help write the article. Either way, it's probably not a good idea to be creating an article if you're dependent on the ref. desk for material.--RDBury (talk) 12:02, 31 December 2009 (UTC)
The prod on this was declined by an uninvolved admin, so Wikipedia:Articles for deletion/All-ones vector. Pcap ping 20:50, 6 January 2010 (UTC)

## Any idea why this isn't working?

Wikipedia:WikiProject Mathematics/Wikipedia 1.0/Analysis and Wikipedia:WikiProject Mathematics/Wikipedia 1.0/Discrete mathematics don't seem to be working, but the other fields like Wikipedia:WikiProject Mathematics/Wikipedia 1.0/Geometry work fine for me. --Robin (talk) 05:52, 5 January 2010 (UTC)

It's because the pages grew too large. The hidden category on the broken pages was a symptom of this. I added a parameter to the templates on those two pages that makes them work again, by not putting so much data on one page.
The new WP 1.0 bot is going to include the ability to generate the per-field tables, and I was working on that just yesterday. I added talk page categories for the fields a couple weeks ago, so you can already use the lists feature of the new WP 1.0 bot to make a list of articles in a particular field (e.g. Analysis). This should also make it easier to use other tools that are based on category intersection. The list of categories is at {{maths rating}}. — Carl (CBM · talk) 11:04, 5 January 2010 (UTC)
Ok, thanks. --Robin (talk) 14:15, 5 January 2010 (UTC)

## RfC on recent changes to Bivector

I've attached a RfC to Talk:Bivector#Problems with second paragraph, but as it's primarily a mathematics issue I thought I'd mention it here too. It's just me and User:Brews ohare working on the article who seem never to see eye-to-eye on anything, so we could do with other viewpoints. --John Blackburne (wordsdeeds) 17:01, 6 January 2010 (UTC)

## Computational complexity theory as part of "mathematics"

I noticed that the list of mathematical articles had some complexity theory articles, like P versus NP problem, Cook–Levin theorem, Karp's 21 NP-complete problems and PCP theorem, but does not have articles P (complexity), BPP or Karp–Lipton theorem. I realized that the reason for this is that Category:computational complexity theory is not part of list of mathematics categories. I would like to propose that Category:computational complexity theory be considered as "mathematics" on Wikipedia and this category be added to list of mathematics categories. I personally believe that complexity theory is mathematics. The biggest open question of complexity theory , the P versus NP problem is considered to be one of the biggest open problems in mathematics, not just computer science. Also, for example, The Princeton Companion to Mathematics lists computational complexity theory as one of the branches of mathematics. (See table of contents which lists 26 branches, and complexity theory is the 3rd one on the list.) What do people feel about this? --Robin (talk) 03:57, 4 January 2010 (UTC)

If we put Category:computational complexity theory in list of mathematics categories, then mathbot will put all the articles in that complexity category into the list of mathematics articles. There is a lot of non-mathematics there, such as Electronic Colloquium on Computational Complexity, Molecular models of DNA, etc. The whole category smacks of hard computer science to me. Perhaps a few articles from there can be added by hand to the list of mathematics articles, rather than having the bot automatically add any articles there to the list. Oleg Alexandrov (talk) 04:03, 4 January 2010 (UTC)
True, but such stuff always creeps in when we add any sufficiently large category to list of math categories. For instance, Category:Graph theory brings with it articles like Small world routing and Liquid schedule, which seem quite non-mathematical. Moreover, the current list of mathematical categories does include categories that I would think are way more computer science than complexity theory. E.g., Category:Arbitrary precision algorithms, Category:FFT algorithms, Category:Computational geometry, Category:Optimization algorithms and Category:Dynamic programming, which leads to articles like Artificial Bee Colony Algorithm and Swarm intelligence. I'm not saying WP:Other stuff exists, but some primarily math categories will inevitably bring along some non-math, and this is not specific to only Category:computational complexity theory. --Robin (talk) 04:29, 4 January 2010 (UTC)
Molecular models of DNA was a bad example — it was heavily overcategorized and should not have been in the category in the first place. I removed it. —David Eppstein (talk) 05:02, 4 January 2010 (UTC)
I support adding that category to List of mathematics categories. CRGreathouse (t | c) 14:37, 4 January 2010 (UTC)
There's a gazillion of non-math in there, such as AI-complete, DNA Dynamics, Randomness extractor, Circuit complexity, Unary language, etc. Besides, the article Computational complexity theory itself clearly says that this is part of computer science.
Adding this category to the list of math categories is not a big deal, but who will regularly spend time inspecting what articles the bot adds and removing the non-mathematical ones? That is hard enough with mathematics categories, but now we are talking about adding a huge category which is only marginally related to mathematics. Oleg Alexandrov (talk) 19:09, 4 January 2010 (UTC)
DNA Dynamics was another badly overcategorized article that should have not been in that category at all. Unary language should already be in the math hierarchy by virtue of Category:Formal languages. Randomness extractor and Circuit complexity are no more nor less mathematical than the rest of the category — there is no reason to include the rest of the category and manually exclude them. AI-complete is a bit of a border case (and a questionable inclusion in the category) but we're never going to have a system that avoids border cases and I think the number of them is quite small. —David Eppstein (talk) 01:57, 5 January 2010 (UTC)
Indeed, Randomness extractor and Circuit complexity are standard complexity theory articles, and are examples of exactly the sort of articles I'm proposing we include in the list of mathematical articles. --Robin (talk) 02:41, 5 January 2010 (UTC)
I guess this is dvelving into the ideological and pragmatic divide between mathematics and TCS. There will obviously be different opinions on dealing with this. I had a long discussion with User:Arthur Rubin in the past on dealing with Category:type theory, which contains mostly topics of interest to computer scientists nowadays. I think the pragmatic approach is to ask: which topics of TCS (computational complexity in this case) are generally of interest to mathematicians? And add just those articles to the math lists, possibly creating a helper category. Pcap ping 14:08, 5 January 2010 (UTC)
I think it's more of a philosophical question: does the math hierarchy include only mathematics of interest to mathematicians in research mathematics departments (in which case for the math department in my university much of combinatorics would be excluded) or does it include as well subjects such as statistics, computational complexity theory, etc. that are treated by their practitioners as rigorous mathematical subjects but that are largely sorted into other departments in our research universities? The Clay math prizes obviously took an inclusionary approach, including problems from complexity theory (P vs NP) and fluid dynamics in their million dollar prize problems. But we don't have to follow their lead if we want to be more exclusionary and focussed. —David Eppstein (talk) 15:57, 5 January 2010 (UTC)
I have no problem adding this category. I'll ask more folks to comment though. Oleg Alexandrov (talk) 17:09, 5 January 2010 (UTC)
As far as I am concerned, anything that can be formalized as a theorem of ZFC is mathematics (not necessarily vice versa). The bulk of computational complexity is mathematics, hence inclusion of this category is quite appropriate. — Emil J. 17:45, 5 January 2010 (UTC)
In addition to what David Eppstein said, besides the Clay math institute, many institutes and people share a similar belief. For instance, Avi Wigderson, who is a complexity theorist, is a faculty member of the school of mathematics [11] at the Institute for Advanced Study, Princeton. And as I said before, the fields medalist and editor of The Princeton Companion to Mathematics, Timothy Gowers, lists computational complexity theory as one of the branches of mathematics. --Robin (talk) 18:40, 5 January 2010 (UTC)
I'm comfortable calling most of these articles mathematics.
However it might be good to ask at WikiProject CS and see what they think. It can come across as arrogant to start categorizing things as part of one's own field, if the workers focused on that field don't see it that way. There's a very irritating contributor who every now and then changes the opening sentence of set theory to make the bizarre claim that set theory is a branch of computer science. A few cybernetics editors have a similar overreach. I wouldn't want us to be seen as engaging in the same sort of imperialism. --Trovatore (talk) 18:48, 5 January 2010 (UTC)
Categories are devices for finding articles you do want? False negatives should be more of a worry than false positives, really. Go back six years and there was plenty of physics listed as mathematics. It was a good idea to weed out those articles, but it is much less clear that computer science connections should be treated in the same way. Save energies for who gets tenure :-( Charles Matthews (talk) 20:53, 5 January 2010 (UTC)
Just a tangent on that: Certainly that's part of what categories are (although I personally rarely use them to find articles — would be interested in hearing others' practices on this).
But categories also, in practice if not by design, take a position on how human knowledge is structured. That can make them targets for POV pushing, especially given that there's no such thing as a citation for a category.
The various pseudo categories, such as category:pseudoscience, are especially problematic in this regard. --Trovatore (talk) 21:30, 6 January 2010 (UTC)

These topics are not math. If wrong categories are applied to an article, they should be removed. Mis-categorization deteriorates the information value to a reader. There is some overlap between CS and math, such as numerical analysis (linear and non-linear algebra) and lambda calculus. Oddly, neither of those two topics is listed in any math category. It looks like we have some work to do. Jehochman Brrr 21:13, 5 January 2010 (UTC) (I supposedly know something about theory of computation.[12])
Lambda calculus is in category:recursion theory, which is a mathematics category.
But I'm not sure which topics exactly you mean by these. Some of them are definitely mathematics by my lights (pretty much everything about the polynomial-time hierarchy, for example). --Trovatore (talk) 21:54, 5 January 2010 (UTC)
Considerations of what else is in what categories aside, I would argue that computational complexity theory belongs as much as, say, algeabraic topology does. don't be decieved by the "computational" part of computational complexity theory. computational complexity theory makes rigorous mathematical statements about, well, mathematical statements. Part of the beauty is, like algeabraic topology, those statements apply regardless of what language one chooses to express their mathematical statements in; regardless of the formal system. It can tell you how many times a symbol is traversed in relation to the number of, say, vertices of a graph. Much like things in set theory or geometry do. It's a mathematically rigourous way of analyzing a formal structure - or one might say a set of formal structure spaces. point is, it is pure mathematics at its best. Kevin Baastalk 21:45, 6 January 2010 (UTC)

### Computational complexity theory added, help requested

I added Category:computational complexity theory to the list of mathematics categories, per the comments above. At the next bot run it will add the articles from that cat to the list of mathematics articles.

It would be nice if folks knowledgeable in this area could watch User:Mathbot/Changes to mathlists or Wikipedia:WikiProject Mathematics/Current activity to see the articles added by the bot due to this change, and fix the category of the non-mathematical articles coming in (as well as removing those articles from the list of math articles).

Also, which subcategories of Category:computational complexity theory should be adopted by our project as well? Oleg Alexandrov (talk) 02:03, 6 January 2010 (UTC)

What do you mean by a "non-mathematical article" — do articles about journals in specific areas of mathematics, or about mathematicians, get counted as mathematical articles, for instance? I am asking because to me the answer is obviously yes but there was a comment above about Electronic Colloquium on Computational Complexity not counting and I'm unsure why not. Also, what is the actual process for removing an article from the list of math articles?
As to what subcategories to also include: probably Category:Circuit complexity, Category:Complexity classes, Category:Computational resources, Category:Descriptive complexity, Category:Probabilistic complexity theory, Category:Probabilistic complexity classes, Category:Quantum complexity theory, and Category:Structural complexity theory. Everything in those categories looks like it could fit equally well within the parent category. But I'm not at all sure about Category:Computational problems and Category:Analysis of algorithms — the former is big and branches off in a different direction than the rest of the complexity theory hierarchy, and the latter really does start to look like CS and not math to me — it's less about formal proofs and more about how one defines mathematical models of the behavior of real computers. —David Eppstein (talk) 17:08, 6 January 2010 (UTC)
I agree. Category:Circuit complexity, Category:Complexity classes, Category:Computational resources, Category:Descriptive complexity, Category:Probabilistic complexity theory, Category:Probabilistic complexity classes, Category:Quantum complexity theory, and Category:Structural complexity theory are standard complexity theory categories, and would fit equally well in the parent category. Category:Computational problems and Category:Analysis of algorithms are a tough call, since the articles in those don't really fit in the parent category. Probably best to not include those two. --Robin (talk) 18:56, 6 January 2010 (UTC)
I guess an article about a mathematical journal is considered mathematical. The mathematicians have their own list. If the bot adds an article which is obviously non-mathematical to the list of mathematics articles, one needs to remove it from any mathematical category, as defined at the list of mathematics categories. Then, one needs to remove the article by hand from the list of mathematics articles. Oleg Alexandrov (talk) 18:52, 6 January 2010 (UTC)
I added the subcategories suggested above. It would be nice if people monitor to see what articles the bot will add from these categories at the next run. Oleg Alexandrov (talk) 22:36, 7 January 2010 (UTC)

### Information theory

A less extensive discussion of this kind took place maybe three or four years ago, concerning Category:Information theory. Many articles in that category are mathematics because they're information theory; others apparently are not mathematics. Michael Hardy (talk) 17:45, 6 January 2010 (UTC)

### Category:Mathematical software and subcats not watched by the mathbot?

I see that Logiweb, which is indirectly part of that category (via Category:Theorem proving software systems) is not being listed in the recent activity for deletion. Is this by design? Pcap ping 23:38, 4 January 2010 (UTC)

It looks like the way it works is there are mathematics categories and mathematics-related categories. Articles in categories on the first list get put into the list of mathematics articles by mathbot and thence to the activity page by a different bot if there is activity. Mathbot ignores categories in the second list. Logiweb is in two categories, Category:Theorem proving software systems and Category:Mathematical software which seem like they might go in the first list, but small changes in the categories tend to made large and sometimes unexpected changes in the lists of articles so care should be used in making any changes. I could be wrong about how it works though; it seems like it should be documented somewhere but I didn't see anything about it except in the code itself. It's a bit disconcerting that we've got WPM specific bots for this, it seems like there should be more universal tools available like the new recognized content bot. It's also a bit disconcerting that Logiweb doesn't appear on any current activity lists. It seems like there shouldn't be any categories that fall through the cracks but it looks like Logiweb is in a couple.--RDBury (talk) 19:04, 7 January 2010 (UTC)
Actually I did find a universal bot you can subscribe by adding the template ArticleAlertbotSubscription to the project page, but articles need to have the WPM banner in the talk page for it to work.--RDBury (talk) 19:55, 7 January 2010 (UTC)

I don't find it disconcerting: we have specific needs, and so it makes sense to use specific bots for them. You're correct that there is one bot that updates the list of mathematics articles, and another that uses that list to check for daily activity. But in general the list of math articles is much more complete than any manually-generated list would be, because we catch new articles automatically as soon as they are put into a category that is on the list.

It seems to me like we should do an audit of mathematics-related categories to see which of them should be added to the list that is watched by the bot. This was done by hand for a while by the bot operators, I believe, but we can't expect them to commit to doing it indefinitely. — Carl (CBM · talk) 20:23, 7 January 2010 (UTC)

I am adding categories to the list of mathematics categories on a regular basis. See User:Mathbot/New math categories for suggestions. Any help here would be very much appreciated. Oleg Alexandrov (talk) 22:32, 7 January 2010 (UTC)
I'm not sure how specific needs is applicable here. My understanding is that the bot maintaining the List of mathematical articles basically creates a union of a manually updated list of categories. It seems to me that many projects could use a tool like that. It's true we get new article notification quickly, but we also get a lot of false positives and every once in a while there will be days where 20 or 30 new articles show up because a category was moved. I do occasionally try to attack the backlog of Wikipedia:Pages needing attention/Mathematics, but it's suprizing how many of these aren't really mathematical. Do we really want to be responsible for maintaining Squoval for example? Documentation seem to be the most pressing need though. I've been looking at this for a while and am just beginning to understand how it works and unsure about whether by understanding is correct. As to how to respond if someone says article X obviously is/isn't a math article but it isn't/is on the list, I'd still have no idea.--RDBury (talk) 16:58, 8 January 2010 (UTC)
If you see a non-math article that is on the list of math articles, you need to remove it. To make sure that the bot does not add it back, you need to remove that article from a math category. Looking at mathbot's page can clarify a few things as well. Oleg Alexandrov (talk) 17:18, 8 January 2010 (UTC)
That's the kind of thing that needs to be documented so people don't have to spend hours digging through code to figure it out. I think the reason Squoval is there is because it was at some point in Category:Curves, which is legitimate because it is a curve. But that category gets added to the math articles and that's as expected because most curve topics are about mathematical curves.--RDBury (talk) 13:17, 9 January 2010 (UTC)
(Actually, it was in Category:Geometric shapes: [13].) — Emil J. 15:51, 9 January 2010 (UTC)

Quick note: the subcat Category:Spreadsheet software should definitely not be added. Pcap ping 17:30, 8 January 2010 (UTC)

## Book:Derivatives

Please give feedback concerning the title of this book on the book's talk page. Headbomb {ταλκκοντριβς – WP Physics} 04:53, 8 January 2010 (UTC)

Misleading title :( Robin (talk) 05:01, 8 January 2010 (UTC)
Which is why there needs to be feedback! Headbomb {ταλκκοντριβς – WP Physics} 05:35, 8 January 2010 (UTC)
BackFed :) -- Avi (talk) 05:43, 8 January 2010 (UTC)

Definitely a misleading title. Put brain in gear. Then you won't need further comments beyond that. Michael Hardy (talk) 06:09, 8 January 2010 (UTC)

## To what extent are original research math discussions tolerated in user talk?

Since I don't have the patience to check if most of the stuff discussed there is indeed WP:OR, please see Wikipedia:Miscellany for deletion/User:Linas/Lattice models. Pcap ping 10:30, 9 January 2010 (UTC)

A lot is tolerated in user space. As long as the original research isn't being injected into articles or article talk pages, we ought to leave them be. Jehochman Brrr 10:43, 9 January 2010 (UTC)
I think technically the rule is there shouldn't be OR anywhere on Wikipedia, but I doubt anyone bothers to enforce it in user talk. There are different kinds of OR though, e.g. one user telling another about an new proof of quadratic reciprocity is probably ok, but making libelous statements about someone is bad no matter where you do it. Basically, user talk <> e-mail and anything written there can be read by the general public, so anything potentially harmful to Wikipedia or a user or anyone else should removed.--RDBury (talk) 12:44, 9 January 2010 (UTC)
I believe you are quite mistaken here; WP:OR only applies to mainspace pages and was never intended for projectspace, such as article talk pages, user talk pages etc. In some sense much if not most of what goes on in projectspace involves OR, as well it should. Certainly all the policy and guideline pages themselves are more or less pure OR and there is nothing wrong with that. The problematic conduct in projectspace of the type you mention (such as libelous statements) is ruled out by other policies (not by WP:OR), such as WP:BLP, WP:NOT, WP:CIVIL and the like. Nsk92 (talk) 01:20, 11 January 2010 (UTC)

I don't see how the policy against OR could apply to user talk pages. Those discussions generally should be about editing Wikipedia, but that can cover a lot of ground. Michael Hardy (talk) 19:02, 9 January 2010 (UTC)

Even on an article talk page rather than a user talk page I think some amount of OR should be tolerated, in the form of "I can see that such and such a fact is true — does someone know whether this is OR or whether a source can be found so that we can add it to the article". On the other hand, there is a general rule that material on all pages here (User or whatever) should in some way be about advancing the encyclopedia; this is not so much in WP:OR but WP:NOT. —David Eppstein (talk) 19:24, 9 January 2010 (UTC)
There are some fine lines here. For example when you see editors arguing over something you thought the outside world was in some consensus about, you could point harder to sources for that consensus. But sometimes you might want to bring some unity or clarity to those sources by tying them together in the talk page. At that point the question arises as to how effectively you're allowed to do that. If the answer is "not very" then it makes it harder for Wikipedia to present a coherent picture of a scattered consensus.
As a case in point I felt that the mainstream consensus in the Sokal affair was running against Sokal, and made an effort on its talk page to tie together in one coherent story the many scattered thoughts on it that I'd seen. Although only one person objected to my doing so (I also had positive feedback about it) I could see the logic behind his objection. However I could also see a meta-argument for my argument and gave it there. --Vaughan Pratt (talk) 21:00, 9 January 2010 (UTC)

The OR policy applies to articles, portals, templates, etc., that are supposed to be part of the encyclopedia. It seems very strange to apply it to any kind of talk pages. Talk pages are for discussion of how to improve Wikipedia. Outlawing particular topics a priori in such discussions is not a good idea. Michael Hardy (talk) 01:04, 11 January 2010 (UTC)

I agree; there's no good warrant to apply a blanket ban to such discussion in userspace or even on article talk pages.
On the other hand there's a limit somewhere. I don't know exactly where. I argued keep at Wikipedia:Miscellany for deletion/User:Neptunerover/Theory About Everything, and I still think that would have been the right choice, but it was a reasonably close call, and unfortunately the user in question got everyone (including me) annoyed at him during the discussion. (To be honest, I'm not sure that wasn't his explicit intention.) --Trovatore (talk) 01:28, 11 January 2010 (UTC)

## Bertrand's ballot theorem

An article I worked on extensively last year, Bertrand's ballot theorem, has acquired a 'Too technical' tag. I'm probably biased but I think it has just the right amount of technicality. I'm asking for someone who hasn't worked on the article too much to take a look at it and either remove the tag or offer suggestions as to how to make the language simpler without removing content. I'm thinking the article should be accessible to a bright high school student, though the proofs may require some additional mathematical sophistication. In the mean time I'll try tweak it a bit.--RDBury (talk) 14:46, 13 January 2010 (UTC)

I've also replied on the talk page there. Paul August 16:56, 13 January 2010 (UTC)
It is less technical than most articles in probability theory. Boris Tsirelson (talk) 18:03, 13 January 2010 (UTC)
I added an example section per Paul August. This is really a combinatorics article and the subject has been around since the 19th century when combinatorics was still in its infancy. The article isn't ready for FA status yet but I'm going to at least remove the tag unless there is an objection. 1 too technical tag down, 126 more to go.--RDBury (talk) 19:03, 13 January 2010 (UTC)

The version that was tagged as "too technical" was quite literally the sort of math that secondary school pupils work on. The person who tagged it was offended by the word "clearly" in a sentence that said that if one of the two candidates gets no votes at all, then clearly the other candidate will be ahead throughout the whole counting process. Michael Hardy (talk) 21:15, 13 January 2010 (UTC)

To be fair, that version had a proof in the lead section which is probably not a good idea. I also did a bit of rearranging which seems obvious to me now but probably not a year ago. Thanks to everyone who looked at this.--RDBury (talk) 21:36, 13 January 2010 (UTC)

## Unsigned infinity

The article Limit of a function uses ∞ to mean +∞, in other words a neighborhood of ∞ is a set of the form {xx > c} where c is a fixed number. This seems to be common but by no means universal terminology. The textbook I learned analysis from, A First Course in Analysis by Protter and Morrey, uses three distinct symbols, ∞, +∞ and −∞, where neighborhoods of ∞ are sets of the form {x: |x| > c}. The unsigned infinity and the signed infinities correspond to two compactifications of the real line, namely the Real projective line and the Extended real number line. The sources I looked at seemed pretty evenly divided between the different notations, those at freshman calculus level or less seem to follow the +∞=∞ school while those intended for people specializing in math follow the other (see [14] for example). The article on the extended real number line allows ∞ to be used for +∞ when there is no danger of confusion but there are articles which confuse the two even when there is such danger. This issue would not be a problem if the two notations were consistent; I'm trying to work on the Asymptote article where it naturally comes up and it's turning into something of a roadblock, at least for me. For example the statement

$\lim_{x\rightarrow 0}{1 \over x} = \infty$

would seem to make sense but it is false in the +∞=∞ notation. On the other hand the statement

$\lim_{x\rightarrow 0^+}\log x = \infty$

is true in the other system but looks wrong. So my first question is, do people have a sense of whether one of these notations is predominant? If one is standard then it should be adopted as the standard for Wikipedia and the other should be relegated to a statement somewhere that it's used by some authors. My sense is that if you just looked at calculus books it would look like +∞=∞ is standard notation but it you looked at higher level texts the other would seem to be standard. Certainly having ∞ distinct from +∞ is very useful in complex analysis. So my second question is, if there is no generally accepted standard can we come up with a convention to follow to minimize conflicting usage. This issue has come up before at Wikipedia talk:WikiProject Mathematics/Conventions#Infinity notation but there doesn't seem to have been a consensus. Even if there were a convention it seems like it would be necessary to explain it in every article where it's used since you can't assume that a reader will be familiar with it. But at least readers won't have to figure out from context what the meaning is supposed to be.--RDBury (talk) 18:14, 7 January 2010 (UTC)

Well, it isn't a notational question at all; it's a question of which structure you're working in. There isn't any "standard" answer to that. I guess I would say that tendentially the "unsigned infinity" is more likely to come up in a complex setting than a real-number setting; if you're in a context where you know you're dealing only with real numbers, and not with complex numbers even by implication, then infinities are expected to be signed, and therefore ∞ means +∞. --Trovatore (talk) 21:45, 7 January 2010 (UTC)
As you point out, even if you had a convention, you'd have to explain it in every article. I think this is unavoidable. Also, note that if you did want to write that the limit of 1/x as x → 0 was ∞, then all the time you'd have people misinterpreting ∞ as +∞ and "fixing" it. I think this is probably better said in words, e.g., "As x tends to zero, 1/x tends to get far from zero." If you need to make a precise statement, I think readers are more likely to understand you if you talk about 1/|x|. Ozob (talk) 23:47, 7 January 2010 (UTC)
(ec)Protter and Morrey barely mention complex numbers at all, but they use distinct symbols. So it's not a matter of real vs. complex. Also, if it's a matter of readers going in and fixing things, if half the people reading the article read the notation one way, and half read it the other way, there's potential for it to be "fixed" in either direction, as I was about to do with the Limit of a function article based on what I learned in college. Then I decided to check some other sources which led to me bringing this issue up again. To muddy the waters a bit more, Protter and Morrey somewhat inconsistently use the notation (a,∞) instead of (a,+∞) for {xx > a}. The conclusions I'm drawing at this point are 1) ∞ appearing in a limit has two widely accepted interpretations, 2) neither meaning should be assumed implicitly in an article, 3) most readers will be used to the ∞=+∞ interpretation. For now, I'll try to update the Limit of a function article to represent both interpretations.--RDBury (talk) 14:16, 8 January 2010 (UTC)
Exactly; rather than assuming a convention, one could just say that as x goes to 0, the limit of |1/x| is infinity. That statement is much less likely to be misunderstood, because it is correct under both conventions.
It takes a little experience to get used to the sorts of misinterpretations that people make. My favorite example: there is some article about reasoning that said something like this:
The following statement is false:
3 is an even number.
Multiple editors changed that to "3 is an odd number" without bothering to read the context. There's some benefit in planning for this an writing in a way that makes it less common. — Carl (CBM · talk) 13:10, 8 January 2010 (UTC)

Well now I see two issues here, which I resolve thusly: 1/x as x->0, doesn't much matter which side you're coming from (0+ or 0-) When you actually reach 0, the line is discontinuous and so are all of it's derivatives. So to say that if you move a differential to the right away from the origin, the sign is positive, is disingenuous: the function doesn't have a differential at the origin! Now when you get things like f(x)/g(x) as x->0 where f(x)->0 and g(x)->0, (i.e. you have 0/0) you're kinda in a different situation, because L'hopital's rule states that you just keep taking derivatives of the numerator and denominator until you get something defined - and there's your sign. So whether the inverse of the top part (1/f(x) = 1/0) or the bottom part by itself (1/g(x) = 1/0) was approached from the "right" or "left" side; i.e. whether it was "negative" or "positive" infinity, doesn't matter at all because as soon as you put them together: f(x)/g(x), you get a definite sign no matter which side you come from on either 1/f(x) or 1/g(x). And since a negative times a negative equals a positive and so on, if you work it backwards you see that you can't really put a sign on the infinity when you have just 1/f(x) as x->0 by itself on account of which side you "approach" 0 from, because then it doesn't work out; then composition doesn't hold. so if you want the rules of mathematics to hold and be consistent, and f(x) - > 0 as x -> 0, then 1/f(x) as x -> 0 can't be said to have a sign regardless of which way you "approach" 0 from. In which case I always found the whole positive/negative infinity thing to be quite moot, if not just plain absurd.

Okay, now onto complex infinity: no such thing. you can break down a complex number two ways: real and imaginary part (in which case you have two real infinities), or magnitude and angle. now if you come to an equivalent situation to what i just described for complex numbers, well i would be tempted to say that your magnitude is "positive" infinity and your angle is undefined. but then again i would be just as well to say that your magnitude is negative infinity because well, your angle is undefined, anyways. point being your angle is now what encodes your sign so you might as well just screw the whole "sign of infinity" thing - your magnitude has no sign. and you don't have "complex infinity", you have normal infinity with an undefined phase angle (rho=infinity, theta=?). (Is suppose this is what one might mean by "complex infinity", in which cause ya i guess there "is" but saying so really wouldn't have grabbed your attention as well.)

Having said all that. I don't know what other interpretations there can be of signless infinity than, well, signless infinity. And the context should make it quite clear whether your infinity is signless or "positive". Though I would say that by the point that you start using negative infinity it's just good form to be signing your positive infinities anyways, for consistency's sake, if nothing else. So I say, do it: sign those infinities. But keep in mind that infinity or not, a negative times a negative should always equal a positive. A negative is just a half rotation in the complex plane and two half rotations equals a whole one. Infinity or not. if you can't guarantee that, then there's something wrong with your equation, IMO. I'm not an expert mathematician or anything like that but that's what I have to say about the subject. Kevin Baastalk 21:58, 13 January 2010 (UTC)

Actually there's no problem with complex numbers. The extended complex numbers have only 1 infinity. There is no sign. The problem is with the reals due to different ways to extend the real numbers to include infinity (Real projective line and the Extended real number line). I don't have any useful suggestions to offer for the real number case. Just try to make it obvious from context, I guess. If not, perhaps try using notation that would be least confusing, or offer a short explanation? --Robin (talk) 22:49, 13 January 2010 (UTC)
Okay, so I see: the real projective line arises because of the whole wavelength = 1/frequency thing, as exemplified by things like 1/f(x) as x->0 and cosh(x). And the extended real number line is because, well, not all functions are like that. e.g. f(x)=x^2 (and maybe fourier transforming a function or something like that can move it back and forth between the real projective and real extended lines) Then I'd say sign any infinities on the extended real number line, and don't sign any on the real projective line. i.e. i reaffirm my "sign it" position. That would be "least confusing". (I suppose that's a simpler way to say my whole l'hopital's rule thing, because when signing an infinity would break composition, rest assured you're on the real projective line.) Kevin Baastalk 15:29, 14 January 2010 (UTC)
looking at the asymptote page, I see them using +/- infinity for functions on the projective real line. I think that's clear. Maybe even better than unsigned infinity, because it distinguishes between real projective line infinity and complex infinity. I'd say go with that convention: sign on the extended line, +/- on the projective line, and just plain infinity on the extended complex plane. Kevin Baastalk 15:51, 14 January 2010 (UTC)

## Chaosbrot - OR ?

The author of chaosbrot, User:Doomed Rasher, is so far unable to provide sources for this generalisation of the Mandelbrot set, but claims the article is not OR because it is a "simple calculation" - see discussion at my talk page. Thoughts ? Gandalf61 (talk) 16:39, 9 January 2010 (UTC)

An article can't consist only of "simple calculation". Looks like OR to me, and probably needs to be deleted. Paul August 21:27, 9 January 2010 (UTC)
The chaosbrot author (who I agree seems also to be Doomed Rasher) writes the following: "I was messing around with Project Euler one day and dug up an old applet that I had written. It turned out that I could define a whole family of fractals from it, so I decided to patch the applet with a slider and text box so a user could define arbitrary values to see different fractals. My blog post has the download link and more details on how it actually works, or you can consult the relevant wikipedia article."
DR argues at User talk:Gandalf61 that the chaosbrot article deserves the same treatment as Gravity set. What this ignores is that the gravity set (a nice idea) was invented long ago by Chris Green at Atari, even before there were any browsers let alone Wikipedia, and that others such as Green's coworker Fred Mitchell at Atari and Jason Rampe in Australia have since taken an active interest in it, with Mitchell now promoting himself as its creator and with Rampe adding gravity-set images at http://softology.com.au/gallery/gallerygravity.htm to his wide range of Mandelbrot images, which he makes a business selling. If anybody but DR had found even that much redeeming value in chaosbrot a case might be made for it. As it stands, what is there about "chaosbrot" to distinguish it from promotion of a program by its author?
What DR could argue much more convincingly is that Fred Mitchell (mathematics) deserves the same treatment as chaosbrot, since Mitchell's main claim to fame seems to be as the programmer who translated Green's program from Forth to C, added a GUI, and (according to Gravity set) "discovered the incredible richness in the gravity set by manipulating the many parameters involved." The last paragraph of the Mitchell article reads "Currently, Fred Mitchell is working on a new mathematical system to describe networks of arbitrary complexity and structure. Nobody cares. He has also taken a keen interest in molecular biology in his hopes to understand the mechanism of life and death in deeper detail." User talk:Flajann comments in an edit summary, "Someone keeps vandalizing my page. I am putting it back to what it should be." The word "my" here suggests two problems: (a) WP:OWN and (b) Mitchell wrote his own biography under the name Flajann. --Vaughan Pratt (talk) 23:18, 9 January 2010 (UTC)
Please note that assertions about "conflict of interest" are problematic on two fronts: one, issues of "attempted outing"; two, the merits of material and our view of its inclusion should have nothing to do with who typed it in (among users in good standing). Charles Matthews (talk) 14:25, 10 January 2010 (UTC)
It's not outing if the editor links to his real name facebook profile on his user page. Pcap ping 16:47, 10 January 2010 (UTC)
Fred Mitchell (mathematics) fails our standards for inclusion. I've prodded the article, but I suspect an AfD will be necessary. Pcap ping 23:48, 9 January 2010 (UTC)
Notability is established by references, which the article has none of. A quick google finds only references that would do little to establish notability and suggest this is just OR and self promotion. As for simple calculations, that excuses you from doing or providing references for the intermediate steps of a calculation if an average reader for the topic could do the calculation themselves. It does nothing to establish the notability of the topic. If there wasn't already a discussion here I'd be tempted to start one at AfD.
And what other articles exist is irrelevant, as per WP:OTHERSTUFF. If other articles are on non-notable topics then it's something that should be raised on those articles talk pages, or via one of the various merge and deletion nomination processes. Unless it's a proposal to merge them all together into a Generalisations of the Mandelbrot set article they should all be addressed separately. --JohnBlackburnewordsdeeds 23:33, 9 January 2010 (UTC)
So, is there a consensus that chaosbrot should be raised at AfD for wider community discussion ? Gandalf61 (talk) 09:38, 10 January 2010 (UTC)
Looks like Afd material to me.--RDBury (talk) 12:42, 10 January 2010 (UTC)
I AfD'ed the article since I do agree that the arbitrary name of "Chaosbrot" is by itself unnotable and not supported by references, but it remains questionable whether or not the same generalization has been published before under a different name. Suggest merging to Mandelbrot_set#Generalizations and removing references to "chaosbrot".
This pretty much establishes that Flajann = Mitchell Green and that he censors WP talk pages. Per WP:ENN, a commercial website/image gallery does not qualify as a reliable source for Gravity set, consider adding reliable references to the gravity set article other than the creator's website and a gallery of images. Doomed Rasher (talk) 16:20, 10 January 2010 (UTC)
'pretty much establshes'? I looked this over, and the article probably does, at best, deserve movement to the generalizations section with no name attached; but and also a 7-year-ago single small example to me says more about the person citing it than the person who did it.Julzes (talk) 13:32, 12 January 2010 (UTC)
I agree that that was a flub by a newbie - Flajann responded to a comment by overwriting it; we might all have done that in our first days of editing. This, however, is his most recent edit - and the most extensive and explicit legal threat I have seen in some time. Septentrionalis PMAnderson 01:46, 15 January 2010 (UTC)
To be fair, he was reacting to this (the "Friends report..." part). Flagged revisions might have prevented it, but having poorly sourced biographies of people that few watch-list seems just as bad. Pcap ping 02:07, 15 January 2010 (UTC)
I blocked Flajann (talk · contribs) per WP:NLT, but see also Wikipedia:Don't overlook legal threats. —David Eppstein (talk) 04:00, 15 January 2010 (UTC)
Shouldn't you be blocking the editor that added the presumably libelous material too, User:Genicity? It seems to be a WP:SPA who only edited that bio for apparently not so noble purposes. Doesn't seem to be here to build an encyclopedia: [15] [16] [17]a. Pcap ping 05:01, 15 January 2010 (UTC)
Ok, I left a standardized warning message on Genicity's user talk page. I don't think it rises to the level of an immediately-blockable offense the way the legal threat does. —David Eppstein (talk) 07:44, 15 January 2010 (UTC)

### Gravity Set

Does anyone here think that fractal article should be kept? I can't find secondary references about it, and given the history of WP:COI edits of the article's creator, I'm tempted to AfD it too. The only 3rd party program known to implement it is Visions Of Chaos [18] (looks cool though). Pcap ping 08:18, 15 January 2010 (UTC)

Looking at Gravity set#Mathematics, I'm not sure that calling it a fractal is justified. The graphics seems derived from a sort of simulation of an n-body problem. Pcap ping 08:51, 15 January 2010 (UTC)

I also think that the article does not establish notability. Please AfD it to obtain consensus. Geometry guy 11:09, 15 January 2010 (UTC)
Wikipedia:Articles for deletion/Gravity set. Pcap ping 19:44, 15 January 2010 (UTC)

## Progress on /Proofs articles.

See Wikipedia talk:WikiProject Mathematics/Proofs if you're interested. Crossposting here in case people aren't monitoring the other page.--RDBury (talk) 16:26, 16 January 2010 (UTC)

## Polynomial function

Someone created a new article titled Polynomial Functions, plural and with a capital F. I moved it to polynomial function, which formerly redirected to a section of polynomial. The article should either get a lot of work or get redirected as before, in which latter case if something is worth keeping it should get accordinginly merged. Michael Hardy (talk) 03:31, 18 January 2010 (UTC)

I haven't looked at the article in detail but I'd be surprised and a bit disappointed if a standard pre-calc subject like that wasn't already covered completely.--RDBury (talk) 07:53, 18 January 2010 (UTC)
I've looked at the article more carefully and it appears that much of the material is elsewhere. The article is being expanded but it looks like the editor is ignoring the advisory about not duplicating material.--RDBury (talk) 15:16, 18 January 2010 (UTC)
I identified other articles with the same material, see the update history for details, and turned the article back into a redirect. There is an argument that there should be a summary article that links all this material but that would be polynomial.--RDBury (talk) 18:06, 18 January 2010 (UTC)

## Certain widows

The only even prime number is 2.
This equation is to be solved for x.
Suppose there exists an odd perfect number n.

It would be unseemly to read the first of the sentences above in a book with the word "is" at the end of the line at the bottom of the page and then turn the page to find only the "2" and an otherwise blank page, and similar comments apply to the other two examples. In typography, a lonely last word at the top of the page is called a widow. A less extreme situation would be the "2", the "x", or the "n" in the examples above being the first character on the next line after the "is", the "for", or the "number" appears as the last item on the previous line. Hence I've set them with "nbsp" between the word and the final character. I've also been doing that in articles when things like this appear:

One seeks the solution x of the second equation above.

so that it won't appear as

One seeks the solution
x of the second equation above.

Is this worth prescribing in WP:MOSMATH? Michael Hardy (talk) 16:29, 16 January 2010 (UTC)

This seems pretty hostile to editors not used to writing html. I'd rather have a very rare ugly paragraph than confuse some would-be contributors and muddy the wiki syntax. Staecker (talk) 16:37, 16 January 2010 (UTC)
I think if the article is being cleaned up for FA status it should be something to add to the to do list, but there are other priorities in general. For example there is a backlog of over 1000 articles with an unreferenced tag. I personally have a hard enough time remembering to put nbsp inside ordered pairs.--RDBury (talk) 18:52, 16 January 2010 (UTC)
That sounds about right to me. It is always an improvement to prevent bad widows like this, but in most cases it does not have as big a cost-benefit ratio as other improvements (where the cost is the editor's time that could be spent constructively doing something else). It should certainly not be something that rises to the level of warning other editors that their edits are subpar because they neglected to do this. —David Eppstein (talk) 21:35, 16 January 2010 (UTC)
To me this is not a problem just for maths but one that could be seen in other contexts: dates and times, numbers, words, names like "Toys 'R' Us", etc.. As such it would be best addressed by WP as a whole, not just by mathematicians, if it needs addressing. I don't know if there's anything in HTML, or in a future version of HTML, that would handle this: a paragraph style or style hint. It's something I think word processors have been able to do for years so I'd be surprised if it's not been looked at. But it's also in part addressed by the nature of the web. If a user finds something difficult to read they can always increase or decrease the font size, adjust the window size, change their browser settings and often as here change per-site settings to make things more or less readable.--JohnBlackburnewordsdeeds 21:57, 16 January 2010 (UTC)

That is something that imho needs to be solved on a software level, if it is perceived as serious problem at all. Generally it seems to me like a rather bad idea to let display issues dictate your writing style or structure of your sentences. WP:MOSMATH is already big enough as it is and as pointed out above there are plenty of more pressing issues than this.--Kmhkmh (talk) 20:13, 19 January 2010 (UTC)

## Goedel picture

The photo of Kurt Goedel has been deleted on the grounds that it didn't have a fair-use rationale. Surely this is a clear-cut one; free-licensed pictures of the man are going to be hard to come by. --Trovatore (talk) 08:41, 19 January 2010 (UTC)

This is iffy because you can't argue it's needed for critical commentary—he isn't famous for his looks. On the other hand, I'd think some picture from his youth would be out of copyright by now. Pcap ping 08:46, 19 January 2010 (UTC)
I replaced it with the (rather poor quality one) from MFO found on commons. Pcap ping 08:51, 19 January 2010 (UTC)
Ah, that's a pity. I hate to see quality go down because of the unreasonably restrictive rules on fair use. We need to defend fair use by using it; we need to make sure the lawmakers understand that it has a constituency.
But with the rules as they are, unfortunately, the existence of that photo probably means there's no hope of bringing back the better one. --Trovatore (talk) 08:54, 19 January 2010 (UTC)

## Edit war?

Something of a edit.....disagreement...seems to have broken out at Negative binomial distribution. I expressed some views a few weeks ago on the talk page. I haven't yet looked at this latest skirmish very closely, but maybe I will later today. Michael Hardy (talk) 19:09, 19 January 2010 (UTC)

How many other people see this? Quite often for me a displayed formula starting with :$is not indented in the standard fashion. I use Firefox. I haven't found any systematic reason why this happens. Charles Matthews (talk) 14:58, 20 January 2010 (UTC) I don't recall ever seeing this (I use Safari). Can you give examples? Paul August 15:24, 20 January 2010 (UTC) I also can't think of a time I've seen this, and I use Firefox. CRGreathouse (t | c) 15:26, 20 January 2010 (UTC) Is it consistent, or does it come and go for the same formula without editing? An example that other people could look at would be a great help diagnosing it. — Carl (CBM · talk) 15:29, 20 January 2010 (UTC) I'm seeing this now for Hypergeometric series#Notation, first displayed formula only (with the betas), and the rendering is not the standard font. Just that one formula in the whole article. Charles Matthews (talk) 15:44, 20 January 2010 (UTC) It seems to use HTML rendering. Try adding \, to force PNG rendering? — Miym (talk) 15:50, 20 January 2010 (UTC) ## Sigma-algebra too technical? The article Sigma-algebra's talk page has had the "Too technical" template added to it. Since I saw no discussion on the talk page about the reasons for the template's addition, and since, in my opinion, the article is at about the right technical level for the likely or intended audience, I removed the template. But my edit was reverted, so I'm attempting to start a discussion here. In particular I'd like to know other editor's opinions on this article, the reasons why this article might be thought too technical, and for suggestions for how this article might be made usefully less technical. Paul August 15:31, 20 January 2010 (UTC) The editor who originally tagged the article, User:Stpasha, has been quite active over the lasts couple days, so you could maybe post a query on their talk page ? Their edit comment when they tagged was "the lead section must at least make an attempt to explain the concept in layman terms". Maybe they are looking for a sentence in the lead such as "Informally, a sigma-algebra is like an xxx with a bit of yyy and some zzz" - although I must confess I wouldn't know how to give an informal description in this case. Gandalf61 (talk) 15:48, 20 January 2010 (UTC) Thanks I've notified Stpasha on their talk page. Paul August 15:53, 20 January 2010 (UTC) What I find much more puzzling on the Sigma-algebra talk page is the {{Reqequation}} template. Does anyone have an idea what's this request supposed to mean? — Emil J. 16:11, 20 January 2010 (UTC) As I understand it, that template is asking for an image (in particular an image of an equation) be added to the article (see this edit). I can't think at the moment of what an appropriate image might be — I certainly don't think an image of an equation is needed. Paul August 16:27, 20 January 2010 (UTC) A crazy template. I mean "Reqequation"; requesting an image is OK with me. What about Template for Delete? Boris Tsirelson (talk) 16:38, 20 January 2010 (UTC) I agree. Sigma-algebra seems to be the only article where it is currently used, and it's very hard to think of a legitimate use. Hans Adler 17:47, 20 January 2010 (UTC) It is used at RAMDAC also. Algebraist 17:50, 20 January 2010 (UTC) Thanks, I missed that. And of course it's equally silly there. Hans Adler 18:57, 20 January 2010 (UTC) After reading the article and the comments on the talk page, I realized that I had been misunderstanding what "too technical" meant, at least in this case. Since others commenting on this page seems to have the same misunderstand, I will try to explain. "Too technical" does not mean "too advanced" or "too difficult". Indeed, the definition given in the article was quite clear: a sigma algebra on a set X is a collection of subsets of X closed under complements and countable unions. But this definition is too technical: it tells you nothing about what a sigma algebra is for, why it is defined as it is, or why it is considered interesting. The technical details are correct, but the sense is missing. It seems to me that this misunderstanding of "too technical" is a recurring minor problem in this WikiProject: someone will post that an article is too technical, and the project members will respond as if the complaint were instead that the article was too advanced. I believe I have done this in the past, and I hope I and others will be able to understand these complaints better in the future. —Dominus (talk) 18:01, 20 January 2010 (UTC) If they have that misunderstanding, I think the text of the template is to blame. The {{context}} template is friendly and easy to understand. I know how to address it. But the {{technical}} template comes across as "I didn't understand this article" or "this needs to be dumbed down". And I have no idea how to address it based on the text of the template. — Carl (CBM · talk) 20:09, 20 January 2010 (UTC) There's also {{cleanup-jargon}} — often appropriate on our math articles, but the part about either simplifying or explaining could again be misinterpreted as "this needs to be dumbed down". —David Eppstein (talk) 21:22, 20 January 2010 (UTC) Being the previous person to ask for help in resolving a "too technical" tag, I'd say it's partly the tag and partly that many editors feel free to add vague tags without explaining what they are referring to. For the article in question here it seems pretty clear that there's no reason to expect someone who hasn't taken a couple of real analysis courses to be able to follow it. Wikipedia is supposed to serve a range of audiences, from grade schoolers to post-graduates. When people stumble across an article meant for a more advanced audience they are bound to get confused and sometimes they complain. On the other hand, sometimes the complaint is justified when an otherwise elementary topic is written as if the only people who might want to read it have Ph.D.s. In an ideal world every article would have a prerequisite tag somewhere so people who come across it will know what to expect and editors will be warned not to have an article meant for high school students be primarily about algebraic number theory. But I expect that idea is impractical.--RDBury (talk) 21:47, 20 January 2010 (UTC) I guess, for "sigma-algebra" there exists a more specific cause: undergraduates study probability and see probability space (triple) with sigma-algebra; however, they see only countable probability spaces; thus they are puzzled, why the fuss. See probability space. Boris Tsirelson (talk) 06:34, 21 January 2010 (UTC) ## Proof in Bernstein polynomial There was an RfC for the proof in Bernstein polynomial. I looked at it and it seems use a probabilistic proof of uniform convergence of a series of polynomials to a given function f. It is, at best, hard to follow and there is some question as to whether it's valid. It could use more eyes on it.--RDBury (talk) 13:32, 21 January 2010 (UTC) I did; see the talk there. Boris Tsirelson (talk) 20:50, 21 January 2010 (UTC) ## Addition of natural numbers I have proposed merging Addition of natural numbers into Natural number#algebraic properties. Please feel free to comment at Talk:Natural number#merger. — Carl (CBM · talk) 16:47, 21 January 2010 (UTC) ## WP 1.0 bot announcement This message is being sent to each WikiProject that participates in the WP 1.0 assessment system. On Saturday, January 23, 2010, the WP 1.0 bot will be upgraded. Your project does not need to take any action, but the appearance of your project's summary table will change. The upgrade will make many new, optional features available to all WikiProjects. Additional information is available at the WP 1.0 project homepage. — Carl (CBM · talk) 03:35, 22 January 2010 (UTC) In case you wonder: this is separate from VeblenBot, although eventually the new WP 1.0 system will replace VeblenBot as well. — Carl (CBM · talk) 03:36, 22 January 2010 (UTC) ## Prototile Prototile is a fairly weak effort that could use some work. Michael Hardy (talk) 18:57, 21 January 2010 (UTC) I'm more concerned that it's used in the first sentence of Penrose tiling with no definition. So an a reader comes to an article with a fair amount of coverage in the popular press and is immediately confronted with a word that not even professional mathematicians are familiar with, and is sent to a poorly written and unreferenced article to get the meaning. This is unacceptable writing style in a highly visible article.--RDBury (talk) 14:38, 22 January 2010 (UTC) ## New page header I took the liberty of adding a page header with links to related talk pages. If it's going to break something then delete it but otherwise I think it will be useful.--RDBury (talk) 05:29, 22 January 2010 (UTC) Looks good to me. Paul August 19:12, 22 January 2010 (UTC) ## Coxeter graphs are also a family of graphs. Hello, right now there is an article Coxeter graph. This is one very particular graph, named after Coxeter. However, as I know Coxeter graphs, there are plenty (in fact: infinitely many) of them, and they are constructed by use of maximal parabolic subgroups of a Coxeter group. (To add to the confusion, THE Coxeter graph is not one of them!). This is examined in detail in Chapter 10 of Distance-regular Graphs by Brouwer, Cohen and Neumaier, but I don't find many other authors using this term. Coxeter graphs are pretty important, because they include the Johnson graph (when using A_n), the binary Hamming graph (using B_n), a relation of the 24-cell (using F_4), the Schlafli graph (using E_6), the Clebsch graph (using D_5) and the Gosset graph (using E_7). Does anyone have any suggestions for this problem? Evilbu Coxeter was a busy guy so I'm not surprised there are naming conflicts. These things are usually easy to deal with but there isn't a single recipe, see for example Cauchy theorem. In this case maybe you could add a Coxeter graph section (with references of course) to the Coxeter group article and add hat notes with links to straighten out people who land on the wrong article.--RDBury (talk) 13:57, 22 January 2010 (UTC) ## Speed of light FA FYI if you any interest in physics, Speed of light is being groomed to regain FA status. See Wikipedia:Featured article candidates/Speed of light/archive2 for the current discussion.--RDBury (talk) 19:04, 22 January 2010 (UTC) ## Edittools Could you perhaps have a look at the proposal MediaWiki talk:Edittools#Math and logic, and in particular the suggested list of symbols in MediaWiki talk:Edittools#Sandbox? Feel free to edit the list if you think something should be added, removed, or organised differently. Once the list stabilises, we can make a request to add those symbols to the toolbar. — Miym (talk) 18:03, 22 January 2010 (UTC) They've been added - I only just noticed it - so have a look and play and see if you've any thoughts on improving it. I've already suggested a rearrangement, but so far that's been the only feedback (not counting a correction to an error of mine). --JohnBlackburnewordsdeeds 22:28, 23 January 2010 (UTC) ## set function I was surprised to find that set function was a red link. Four articles linked to it. I've created a stub. Work on it. Michael Hardy (talk) 01:23, 23 January 2010 (UTC) It was listed in Wikipedia:Missing science topics but lost amongst a thousand other red links. I think it a problem in general with the WP:MST list that valid subjects are overlooked because there are so many dubious titles to sort through. Imo we should have the Springer EoM & St Andrew's titles by now, at least as redirects. MathWorld titles tend to be somewhat idiosyncratic so I don't think these should be a high priority. I don't use the other sources for WP:MST much so I can't judge.--RDBury (talk) 16:07, 23 January 2010 (UTC) ## Complex icosidodecahedrons Created pages on Wikipedia:Missing science topics. Could someone with more knowledge about this stuff than me do the donkey work on the articles thanks? These are the articles, btw: Thanks again, 4 T C 03:04, 24 January 2010 (UTC) ## sweeping revisions of Cantor's first uncountability proof User:RJGray has extensively revised the article titled Cantor's first uncountability proof (remember here that no matter what "they" say, this is not Cantor's diagonal argument, which came two or three years later). He worked on this for some months in the Talk space and it's finally been moved to the Article space, and I've restored the revisions deleted by the move in order to merge the edit histories. (Apparently the merger takes a while to appear, so if you click on "history" within immediate future minutes, you might not see the merged history.) I don't know who does the "ratings" that appear in the template atop the talk pages. Could those who attend to ratings look this one over to see if a revision of the rating is in order? Michael Hardy (talk) 03:39, 23 January 2010 (UTC) No small group is in charge of ratings. Anyone can change article ratings at any time. The idea (hopefully) is that if enough people change them then the ratings will settle into a correct value over time. If you see a rating that seems wrong, just change it and don't bother to leave a comment. If someone else wants to change it back, they can. — Carl (CBM · talk) 03:55, 23 January 2010 (UTC) I have to say I don't see that as really a recipe for convergence. But that's OK I guess; as far as I can see neither the priority nor the quality rating really matters much. I doubt very many editors are really looking for high-priority, low-quality articles per se to work on; they work on whatever seems interesting at the moment, and what they personally know about. --Trovatore (talk) 04:03, 23 January 2010 (UTC) I suspect that most people will always work on what interests them the most, and that is good for a volunteer project. The rating scale is coarse enough that there aren't too many levels to switch between, which is the only reason to hope for convergence. And I agree that the ratings are not of crucial importance, which is why it is OK if they are not perfectly accurate. However, the ratings are used to select articles for release versions of Wikipedia, so there is some benefit in marking which articles are truly Top-priority versus which are truly Low-priority, etc. But nobody is forced to do that, and ignoring it is perfectly acceptable. — Carl (CBM · talk) 04:08, 23 January 2010 (UTC) I understand very well CBM's point, but just as anyone can edit a math article whether they know any math or not, but nonetheless there are some who know how to do it and some who don't, so also with ratings. Michael Hardy (talk) 06:13, 23 January 2010 (UTC) Maybe I'm in the minority but actually do look for high priority low quality articles to work on. But of those I tend to work on the ones I have an interest in and tend not to work on ones where I don't know much about the subject. I also check article ratings to make sure they're reasonable. To me it's a matter of maximizing benefit for the time invested, benefit being defined as the relative improvement to the article times the number of people who are likely to read it. But I also work on things just because I'm interested in them because I need a bit of fun as well.--RDBury (talk) 15:05, 23 January 2010 (UTC) Based on Wikipedia:WikiProject Mathematics/Wikipedia 1.0/Assessment, I've changed the rating from "B" to "A". Michael Hardy (talk) 20:10, 23 January 2010 (UTC) I have to say that, like mid-size car versus large family car, the ratings business is confused by cultural assumptions. It would not be a bad idea for this project to spell out its assumptions, based precisely on the idea that the transition B → A represents the upgrading of an article from being indicative of the content of a piece of mathematics, to being clearly useful to a student. Or whatever we mean. It is clear enough that things that trickle down from "featured article"/stretch limo are not particularly helpful, and so we should try to peg a more reasonable reference point from which to calibrate. Charles Matthews (talk) 12:02, 24 January 2010 (UTC) There is some description at Wikipedia:WikiProject_Mathematics/Wikipedia_1.0/Grading_scheme; is that what you were looking for? — Carl (CBM · talk) 13:10, 24 January 2010 (UTC) ## A template debate Wikipedia:Templates for discussion/Log/2010 January 23 has a debate on a template allowing referencing of Éléments de géométrie algébrique. Not a mathematical discussion, but still. Charles Matthews (talk) 14:35, 24 January 2010 (UTC) ## 1-th 1-st Hello. In the mathematics must I writing “1-th”? Or must I writing “1-st”? Or is both correct? --Diwas (talk) 12:51, 21 January 2010 (UTC) You mean as an abbreviation for "first"? If so then "1st" would be correct (followed by 2nd, 3rd, 4th, 5th ... nth etc). Paul August 13:17, 21 January 2010 (UTC) Sorry my question was not very precisely. I think about this in Ordinal number So we can freely speak of the γ-th element in the class (with the convention that the “0-th” is the smallest, the “1-th” is the next smallest, and so on). I think n+1th is correct but 1th is not. (in the first minute I saw many 1th but mostly that is (n+1)th, (n-1)th, ... ) --Diwas (talk) 14:54, 21 January 2010 (UTC) Ah. Fixed. — Emil J. 15:26, 21 January 2010 (UTC) Actually, in the given context you can find examples of "1-th", see for example [19]. I have no idea what is standard here. Paul August 15:35, 21 January 2010 (UTC) Regardless of whether its 1th or 1st, this is a bad convention. 0th and 1th are unused in ordinary English but 4th and 247th already have a definite meaning, and this convention is changing that (unless one is attaching great meaning to the dash). Why not say "element number γ", that's hardly longer, and unambiguously means the element that carries number γ, which avoids confusion. Even in ordinary language "object number n" does not have to be synonymous to the n-th object. Personally I am all in favour of starting to count at 0 (I wish we learned out children to count that way...) but the i-th usage is too grained-in to want to give a new meaning, better just avoid it if you don't like it. The best way to make a notion/notation unusable is to give two conflicting meanings to it. Marc van Leeuwen (talk) 08:43, 26 January 2010 (UTC) Hmm? Not at all. We have two (or more) conflicting meanings for lots of stuff in mathematics. We get along alright just the same. Causes occasional minor annoyances; it's no warrant for any heavy-handed attempts to enforce uniformity. In set theory in particular, sequences are ordinarily zero-based; if you want to say "element number γ" you need to make it clear somehow what you mean. Sometimes that'll take care of itself automatically, on the grounds that one meaning will be nonsensical (say, if you talk about a "set of rank ω"). On the linguistic question, I always say "en plus first", never ever ever "*en plus oneth". --Trovatore (talk) 08:49, 26 January 2010 (UTC) ## Formula and Equation I think at the very least the two articles Formula and Equation need to refer to each other explicitly, but I'm not aware of any formal distinction of the two terms so I don't know how to go about that. In the extreme case perhaps these two articles could be merged. Does anyone have any suggestions? Cheers, Ben (talk) 12:07, 22 January 2010 (UTC) The thing they have in common is they involve mathematical expressions. They look similar as they're both expressions with equals signs, but they are quite different. Formulae are expressions that express a relationship, equations are expressions that need to be solved. They both link to expression and are linked from there, so in that way the relationship is already established. --JohnBlackburnewordsdeeds 12:30, 22 January 2010 (UTC) Hmm, so would you say that x2 + y2 = 1 is a formula or an equation? Ben (talk) 12:53, 22 January 2010 (UTC) It's the equation of a circle, in particular the unit circle centre the origin. Alternately it's an equation with the solution being the set of all points a distance 1 from the origin in the x-y plane. --JohnBlackburnewordsdeeds 13:08, 22 January 2010 (UTC) A better example might be r2 = x2 + y2. It's an equation for a circle and a formula for computing distance. The distinction is one of viewpoint, a mathematician wants to understand the implications of an equation, a carpenter wants to know how long to cut a board to make a diagonal brace. I'd also throw the article Expression (mathematics) into the mix (it even has a note saying it contradicts Formula.) They all need to at least refer to each other. The present formula article is dreadful. A merge with equation could work as long as the practical viewpoint is preserved. (I just found Formulation and Formulations, lots of mess to clean up.)--agr (talk) 13:39, 22 January 2010 (UTC) I would say that the "formula" there is x2 + y2, and the "equation" r2 = x2 + y2 says that the square of the distance is given by that formula. That is, a formula is something that returns a value when you substitute inputs, and an equation joins two formulas with an = sign. However, it is very common ignore this distance and call the equation itself a formula, particularly if one of the sides is a single variable, and particularly in elementary classes. But I would say that the formula for the area of a circle is "πr2", not "A = πr2". — Carl (CBM · talk) 13:45, 22 January 2010 (UTC) I think that equation means "a statement that some things are equal" (they "equate"), and that formula means "a generic statement involving mathematical symbols". Using that definition 2 > x is a formula, but not an equation. See [20] and [21] for example. Gabbe (talk) 13:43, 22 January 2010 (UTC) This is certainly the meaning when people "display a formula" in TeX. — Carl (CBM · talk) 13:45, 22 January 2010 (UTC) I tend to think of a formula as "a formula for ...", so the above example would become a fomula for r if written $r = \sqrt{x^2 + y^2}$ I would call the example 2 > x an inequality: another use for an expression or expressions, not an equation or formula. --JohnBlackburnewordsdeeds 13:56, 22 January 2010 (UTC) (edit conflict) Exactly. By the terminology I used, all equations are formulas, all inequalities are formulas, but inequalities are not equations. Does anybody have any references other than the one I've provided (MathWorld)? Gabbe (talk) 14:05, 22 January 2010 (UTC) To throw a bit more mud in the water, neither of these terms is strictly mathematical. For example every compound has a chemical formula and there are plenty of equations floating around in physics. I'll have to look at the articles but it seems like there are few WP:NOTs that they might be violating.--RDBury (talk) 14:04, 22 January 2010 (UTC) From the math point of view, I'd support the idea that a formula expresses how to calculate a quantity, while an equation indicates two quantities are equal. So in the context of finding area, A = π r2 is a formula, while in a calculation one might inquire when a square and a circle have the same area using the equation a2 = π r2. Solving this equation leads to a formula for the side of square with area equal to the circle: a = √π r. On this basis, equations are a subset of conditions, and formulas are expressions for evaluation of quantities. Brews ohare (talk) 17:15, 22 January 2010 (UTC) I notice that Excel uses the vocabulary "function" for what I'd call the right-hand side of a formula. Here are some example usages of these terms. Brews ohare (talk) 17:39, 22 January 2010 (UTC) We solve equations, but never solve formulas. Here's] an example. That agrees with JohnBlackburne's observation. Brews ohare (talk) 18:20, 22 January 2010 (UTC) Perhaps one definition might be that a formula is an equation with a simple variable on one side and an expression on the other.--agr (talk) 12:43, 24 January 2010 (UTC) The formula $0 \leq p \leq \frac{1}{4}$ is not an equation at all, but it is a formula. JRSpriggs (talk) 22:16, 24 January 2010 (UTC) For me a formula does not even have to include an equals sign; that is just a manner of presentation. I could accept saying that $-b\pm\sqrt{b^2-4c}\over2$ is a formula for the roots of the polynomial X2+bX+c. According to the Abel-Ruffini theorem there is no formula involving only arithmetic operations and radicals for the roots of a general polynomial of degree 5, but there trivially is an equation for them (which of course also involves the equality relation). Note that nothing in the discussion of that theorem ever mentions an equals sign. As for inequalities, I would not classify them as formulas at all. Certainly one can give inequalities for the roots of a general quintic (assuming they are real). Marc van Leeuwen (talk) 09:28, 26 January 2010 (UTC) ## Some eyes on WP:V would be good Someone tried to make autobiographical refs unacceptable, which would be a problem for us since a number of academic BLPs rely on institutional home pages for a number of details. Pcap ping 13:56, 23 January 2010 (UTC) Not a lot of publications are doing features on math professors so in the majority of cases I would think that personal/academic websites are going to the only place you can find personal information. If you've ever tried to do a bio of someone who died b.i. (before internet) you know how big a problem it can be to have to rely just on published resources. You can have lots of material on the person's work but nothing on the date and place of birth.--RDBury (talk) 15:29, 23 January 2010 (UTC) MacTutor is very good on the people it covers; unfortunately that's mostly a subset of our bios. RayTalk 16:58, 23 January 2010 (UTC) How would one write about the life of St. Patrick without using autobiographical sources? Michael Hardy (talk) 19:36, 23 January 2010 (UTC) By using the innumerable secondary sources who have themselves used the autobiographical sources - and in so doing have clarified the problems with them. I doubt any of our mathematicians have their dating disputable by a century, but the principle is the same. Septentrionalis PMAnderson 01:34, 26 January 2010 (UTC) There is a more general problem, for which I don't have any suggestions, but it's worth thinking about. On the one hand, WP:PROF applies to a large number of living mathematicians. On the other hand, many of these mathematicians have little-to-no biographical coverage in published sources. — Carl (CBM · talk) 19:50, 23 January 2010 (UTC) SlimVirgin was just restoring long-standing wording, which does not prohibit autobiographical sources: the key words in "Self-published sources should never be used as third-party sources about living persons" are "third-party". It just says we can't use things like a personal home page or website (institutional pages are arguably published by the institution) as a source about somebody else, who is not the author.John Z (talk) 20:53, 23 January 2010 (UTC) "institutional pages are arguably published by the institution": yes and no. Anyone working or that has worked in academia can tell you they can write almost whatever they want on their institution hosted home page. Surely, making some outright false claims would cause an investigation by some ethics committee, but there's no editorial oversight in the traditional sense of the word. On the other hand, staff catalog entries are somewhat independently written, but there's usually little contents on those. Pcap ping 11:48, 24 January 2010 (UTC) Obviously autobiographical can be used as source (as can interviews and other personal statements). They need however to be treated like primary sources, i.e. be used in a limited and careful fashion and not as neutral third party source. If some editors seriously consider to ban the use of any biographical material in principle, then this needs to blocked/corrected.--Kmhkmh (talk) 12:09, 24 January 2010 (UTC) ## Interval finite element Hi Maths experts. The main author of Interval finite element has created a huge technical article. You've got to admire the extent to which content has been added; perhaps it is being copied from somewhere else? Could someone please review it for {{jargon}}, {{howto}} and {{original research}}? Tayste (talk / contrib) 19:07, 24 January 2010 (UTC) Looking at the history it's pretty obvious that it's the product of many hours of work over a period of several months. My concern would be more about WP:NOTTEXTBOOK.--RDBury (talk) 19:52, 24 January 2010 (UTC) Theoretical engineering, if that's not an oxymoron. First of all it needs general cleanup, starting with the title. I would probably thin it out, trying to preserve the survey nature; but also bring the major points closer to the top (concentric style_. Charles Matthews (talk) 16:27, 26 January 2010 (UTC) ## List of limits The page list of limits is a basic calculus page and apparently has not been developed very much (many famous limits are missing)... this seems strange, maybe there are pages which cover the same topic?--Pokipsy76 (talk) 18:00, 26 January 2010 (UTC) These list of formulas type articles are in kind of a gray area in terms of being encyclopedic. Lists of integrals and related pages are of the same type. You can make a case that the articles should exist, but long indiscriminate lists are against guidelines and these types of articles seem to be natural collection points for just that kind of thing. So I'd say add references and try to establish reasonable criteria for inclusion, but don't start adding tons of new formulas. Abramowitz and Stegun is already online so there isn't a huge need for pages like this.--RDBury (talk) 20:44, 26 January 2010 (UTC) ## Boy's surface/Proofs AfD FYI, the article Boy's surface/Proofs is being considered for deletion here. For some reason it's not showing up on the current activity page.--RDBury (talk) 04:57, 25 January 2010 (UTC) The correct wikilink for the AfD is Wikipedia:Articles for deletion/Boy's surface/Proofs (2nd nomination) (the one you mention above is for the 2007 AfD). Nsk92 (talk) 05:00, 25 January 2010 (UTC) The article is now in current activity; it probably wasn't there before because I missed a step in the deletion process. Thanks for your patience.--RDBury (talk) 18:31, 27 January 2010 (UTC) ## A big mess of many non-notable statistics articles Please see Wikipedia:Articles for deletion/Ligong Chen. (Crossposted to Wikipedia talk:WikiProject Statistics.) —David Eppstein (talk) 01:32, 29 January 2010 (UTC) ## Trapazoid/Vandalism The formulas in the Trapazoid article have recently been tweaked by anon users with no comments. This seems to be a particularly pernicious form of vandalism and general problem, people can go in and make a small change to a complex formula, just enough to make it wrong, and it takes significant time and effort to recheck the formula to make sure the original version was correct. I know Wikipedia:Assume good faith and all that but it seems like it would be more practical to just revert difficult to verify changes to formulas when they are made by anon users, especially if there are no comments.--RDBury (talk) 20:27, 27 January 2010 (UTC) Reverting such unexplained edits as "dubious" is reasonable. Also having a citation that allows easy verification is extremely beneficial in such cases. I always try to add one when I come across edits like this. Paul August 21:42, 27 January 2010 (UTC) I just checked the coefficient 4 inserted by the anon to the formula $A = \frac{(a+b)}{4(b-a)}\sqrt{(s-b)(s-a)(s-b-c)(s-b-d)}$ for a simple-to-check case of b=a+epsilon and d=c. The result: after the suspicious change the formula is definitely wrong; before the change it was hopefully right. Boris Tsirelson (talk) 21:23, 27 January 2010 (UTC) Oops... According to that talk page, notations in the article are inconsistent: a,b,c,d sometimes becomes a,c,b,d or so. I used notations shown on the picture, but I got unsure. Maybe the whole fuss with the formulas happens for this reason? Boris Tsirelson (talk) 21:34, 27 January 2010 (UTC) The formulas are coming from MathWorld, so they are referenced (though MathWorld has been known to have occasional typos). But even when you don't have to derive them from scratch there are still notation issues, different variables used, etc. If it was just this article I wouldn't have brought it up here but I see this kind of thing pop up a lot in my watch list and it struck me that it takes much longer deal with this kind of thing, even if it's not intentional vandalism, than the usual random gibberish that people insert into articles.--RDBury (talk) 05:05, 28 January 2010 (UTC) MathWorld is not really a good source for us, for both procedural and substantive reasons. The procedural reason is that MathWorld, like Wikipedia, is a tertiary source, and what we want are secondary sources with possibly a light mix of primary sources when absolutely necessary. The substantive reason is that MathWorld is idiosyncratic, especially with regard to terminology, and has been known to propagate outright neologisms. --Trovatore (talk) 22:42, 29 January 2010 (UTC) I somewhat disagree with that, though secondary sources are preferable in general, many reputable/reliable tertiary sources are perfectly alright to use, even more so for standard formulas. Note that many math textbooks and special subject encyclopedias (such as Springer's Encyclopaedia of Mathematics) are tertiary sources. Dismissing such tertiary sources is not a good idea from practical perspective alone and you might even argue that they provide an additional layer of error checking and notability for the concerned subject. As for this concrete case I'd agree that (unneeded) formula modifications without proper sourcing or explanation should simply be reverted without furher ado. The same holds for formula edits that might be sourced but are inconsistent with regard to notation and names used throughout the article.--Kmhkmh (talk) 06:12, 30 January 2010 (UTC) Thanks for the help, that should save time in the future. Regarding MathWorld, if I saw an article that used only that as a reference I wouldn't hesitate to add a refimprove tag, but I also wouldn't hesitate to add MathWorld as a reference if it had some relevant information, especially if the article didn't list any other references.--RDBury (talk) 15:47, 30 January 2010 (UTC) I suppose that's reasonable. I have a slight bug up my butt about MathWorld, because of a couple of WP articles that were based on MathWorld neologisms. --Trovatore (talk) 05:16, 31 January 2010 (UTC) ## Edwards curve Edwards curve and twisted Edwards curve need work. Michael Hardy (talk) 04:49, 29 January 2010 (UTC) These are two of a set of articles created by a single editor about current research in cryptography and whose notability is marginal at best.--RDBury (talk) 16:27, 29 January 2010 (UTC) They seem to be referenced. Maybe the level of nitty-gritty detail is excessive. Charles Matthews (talk) 22:56, 29 January 2010 (UTC) I looked on Google last night and found plenty of references. I added a textbook to the article, and I added Edwards's original paper. This seems to be notable in the cryptography community, though I agree that the article as it stands isn't very good. Ozob (talk) 19:12, 30 January 2010 (UTC) ## Displaytitle help Resolved I cannot seem to make Π01 class format its title correctly. Does anyone else have experience with getting subscripts and superscripts into page titles? — Carl (CBM · talk) 14:39, 30 January 2010 (UTC) DISPLAYTITLE is limited in scope. It can't change the "Pi" in the title into a "Π". It would (I think) work if the page was moved to Π01 class, but that triggers the title blacklist for being a mix of latin and greek characters, so I can't make the move. Algebraist 14:46, 30 January 2010 (UTC) Brilliant, thanks. — Carl (CBM · talk) 14:50, 30 January 2010 (UTC) ## Harold Edwards (mathematician) Harold Edwards (mathematician) is a new article. Get busy. Michael Hardy (talk) 04:26, 31 January 2010 (UTC) PS: One of the things to work on is this: find all articles that ought to link to this new article and put the links there. Michael Hardy (talk) 04:27, 31 January 2010 (UTC) Ok, I think I've found most of them. The article itself could still stand improvement (as could most of our mathematical biographies). —David Eppstein (talk) 05:18, 31 January 2010 (UTC) # Feb 2010 ## Mathematical assumption The new page titled mathematical assumption is a mess. Michael Hardy (talk) 06:20, 27 January 2010 (UTC) I've prodded it. --Trovatore (talk) 06:27, 27 January 2010 (UTC) The prod was contested and they added a justification to the talk page.--RDBury (talk) 17:34, 27 January 2010 (UTC) It now redirects to axiom, but a hypothesis in the statement of a theorem is a "mathematical assumption" but not generally an axiom. Michael Hardy (talk) 02:11, 29 January 2010 (UTC) That's true; it isn't a perfect solution. I mused on the talk page that I was not sure whether to redirect to axiom or take it to AfD. Someone else went ahead and redirected, after which I no longer felt strongly enough to bother with it anymore. If someone else wants to, I have no objection. --Trovatore (talk) 02:21, 29 January 2010 (UTC) I was the one who redirected. I don't feel particularly strongly about this, either; but I thought that the redirect was much better than what was previously on that page. I wouldn't object if someone wants to delete mathematical assumption, nor if someone wants to create a new and better article there. Ozob (talk) 15:10, 30 January 2010 (UTC) I wouldn't object to deletion, but I have trouble imagining an article under that title that I wouldn't want to delete. It's a bad habit to start writing articles about phrases whose meanings are more or less clear from their component words. --Trovatore (talk) 09:42, 31 January 2010 (UTC) ## Red cats Is there any reason to add categories to redirect articles? I wouldn't care except they're causing these articles, e.g. Subnormal series, so show up in current activity and List of mathematics articles when they shouldn't be there.--RDBury (talk) 17:02, 29 January 2010 (UTC) They should not be: see WP:RCAT. I've checked and fixed that one. --JohnBlackburnewordsdeeds 17:09, 29 January 2010 (UTC) Thanks, I'll fix any other ones I come across.--RDBury (talk) 18:09, 29 January 2010 (UTC) There are good and bad reasons to add categories to redirects. If I had added one for a good reason I'd be unhappy if it was just taken off. I can't offhand think of obvious examples in mathematics. Charles Matthews (talk) 23:00, 29 January 2010 (UTC) Example: Harborth graph, a redirect to Matchstick graph, is in Category:Individual graphs. The Harborth graph is an individual graph that should be mentioned within that category, but is currently described within the matchstick graph article rather than having its own article. Matchstick graphs are a general family of graphs that should not be in that category because the category is for individual graphs rather than graph families. Putting the category on the redirect means that the category entry is displayed with the name that's appropriate for the category listing. —David Eppstein (talk) 23:25, 29 January 2010 (UTC) The exceptional cases are listed in WP:RCAT.--RDBury (talk) 15:08, 30 January 2010 (UTC) Right, so this one is a clear case of "Redirects whose target title is incompatible with the category" and contradicts your blanket statement at the start of this thread that categories should not be added to redirects. —David Eppstein (talk) 15:56, 30 January 2010 (UTC) Actually that wasn't my statement. But the simplistic version is, if the cat works for the target then add it there, if not then add it to the redirect.--RDBury (talk) 16:15, 31 January 2010 (UTC) Sorry, I meant JohnBlackburne's statement. —David Eppstein (talk) 19:40, 31 January 2010 (UTC) ──────────────────────────────────────────────────────────────────────────────────────────────────── Yes, sorry, my statement oversimplified it somewhat. WP:RCAT says that in general redirects should not be categorised, with a few exceptions. None I think applied to the redirect that started this discussion, which simply caused the article to be listed twice in the same category. But there are exceptions, in particular where the redirect is to something in the article that should be categorised differently to the article as in the above example.--JohnBlackburnewordsdeeds 20:16, 31 January 2010 (UTC) ## Edit war at Euclid In case anyone cares, there is (or was) a rather silly edit war going on at Euclid (talk).--RDBury (talk) 00:19, 1 February 2010 (UTC) ## Multiplicity-one theorem Multiplicity-one theorem is a new article written by someone clearly unfamiliar with Wikipedia usage conventions. It seems to be about group representation theory. Could someone who knows the topic and also knows Wikipedia usages help? Michael Hardy (talk) 04:48, 1 February 2010 (UTC) I'll fix it up a bit before going to bed, and work on it more tomorrow if need be. RobHar (talk) 05:37, 1 February 2010 (UTC) ## Advanced calculus We have no article titled advanced calculus. We never have. (We admins get to see deleted versions if they exist, and in this case they don't.) Should we? Michael Hardy (talk) 04:26, 31 January 2010 (UTC) Is there a standard definition? (I doubt it; each textbook seems to have its own.) Septentrionalis PMAnderson 05:00, 31 January 2010 (UTC) I don't see a need for that article. What would it contain? CRGreathouse (t | c) 06:11, 31 January 2010 (UTC) I don't see the lack of a standard definition as an objection to the existence of the article. (Is there a standard definition of "justice"?) But it should be mentioned in the article. Michael Hardy (talk) 06:39, 31 January 2010 (UTC) BTW, the only course I've taught with "advanced calculus" in the title was more off-the-beaten-path than most. Its content was dictated by the instructors of certain fluid dynamics courses for which it was an essential prerequisite. Half of it was differential equations including Sturm–Liouville theory and generalized Fourier series. I kept wondering if one of the engineering graduate students who were the only demographic there would ask how you know there are "enough" eigenfunctions. No one ever did. The other half was complex variables. After I had mentioned that Cauchy was a 19th-century French mathematician and Liouville was a 19th-century French mathematician, and I think there were one or two more of those, I mentioned the residue theorem, and one student was prepared to hear that Residue was a 19th-century French mathematician. Maybe the lack of a standard definition of the topic could be the article's main point. Michael Hardy (talk) 06:49, 31 January 2010 (UTC) There are also courses "Advanced set theory" and "Advanced probability" in our university; so what? Should WP have such articles? Boris Tsirelson (talk) 07:35, 31 January 2010 (UTC) Well, we have articles on some other standard curriculum elements, pre-algebra and such. But I do think those are a bit more standardized. At Caltech, Advanced Calculus was basically a baby real analysis course. At other schools it may be more about specific methods. --Trovatore (talk) 07:55, 31 January 2010 (UTC) There are plenty of textbooks titled "advanced calculus" [22]. Whether there's any consistent subject that they all cover is a different question that's harder for Google to answer quickly. —David Eppstein (talk) 07:56, 31 January 2010 (UTC) I've taught advanced calculus. As I recall the curriculum covers multivariable and vector calculus in 2 and 3 dimensions, Green's, Stoke's and similar theorems, Taylor's series in multiple variables, not sure what else (it's been a while). Basically anything a sophomore engineering major ought to know about math, but excluding complex variables. I'm not convinced we need articles based on textbook titles; usually these are based on typical college course titles which depend on how material can be divided up into semester long chunks, not on anything to do with the subject matter.--RDBury (talk) 15:58, 31 January 2010 (UTC) +1--Kmhkmh (talk) 16:03, 31 January 2010 (UTC) It seems clear enough that "advanced calculus" is a topic in mathematical pedagogy, rather than in mathematics. Such as pre-algebra, for example. Charles Matthews (talk) 17:03, 31 January 2010 (UTC) I agree. Michael Hardy (talk) 18:00, 31 January 2010 (UTC) Kmhkmh: Your list of topics looks to me like that of what I think of as "sophomore (i.e. 2nd-year) calculus", whereas what I think of as "advanced calculus" comes after that. Michael Hardy (talk) 18:01, 31 January 2010 (UTC) I think you mean RDBury? I didn't list anything at least.--Kmhkmh (talk) 01:15, 1 February 2010 (UTC) Sorry---that's who I meant. Your terse cryptic comment following his comments confused me. Michael Hardy (talk) 05:58, 2 February 2010 (UTC) "+1" is common shorthand for I agree (completely)--Kmhkmh (talk) 07:04, 2 February 2010 (UTC) There are two different meanings to "advanced calculus" that I have seen. The first is what some schools call "calculus 4", which covers about what RDBury listed: Taylor series, the implicit function theorem and its uses, Fourier series, etc. The other is a course that covers Calculus I but with proofs. — Carl (CBM · talk) 18:52, 31 January 2010 (UTC) Following the usual standard shouldn't 'Advanced calculus' mean it is elementary and 'Elements of' or 'Introduction to' require a university degree to approach them? :) Dmcq (talk) 19:13, 31 January 2010 (UTC) Yeah..... Basic Algebra I is for graduate students in mathematics; Advanced Algebra is a remedial high-school course for university students who will never learn what "theorems" or "algorithms" are. Michael Hardy (talk) 06:00, 2 February 2010 (UTC) ## George Kayatta The article titled George Kayatta has a bit more of the element of honesty than it did recently, but could still use some work. For example, it reported that he had been recognized as a "Renaisance Man" (two capital letters). When asked who had recognized him thus (Oxford University? The Pope? His sixth-grade teacher?) someone added a source: a magazine article. Did the magazine bestow that recognition? In fact, the magazine reported that he refused to appear on TV unless introduced in that way. Then it linked to a talk by a mathematician saying, allegedly, that his discoveries would revolutionize mathematics. If you look at that talk, it's about crackpots, one of whom says pi is 25/8, another of whom says the sun is made of ice, and what it says about Kayatta is that someone else (identity unspecified!) said Kayatta's work would revolutionize mathematics. The article could use some more work....... Michael Hardy (talk) 03:06, 1 February 2010 (UTC) Since this post the article was nominated for deletion.--RDBury (talk) 09:55, 1 February 2010 (UTC) ## Wolf Prizes 2010 Wolf Prizes in Mathematics for Dennis Sullivan and Shing-Tung Yau, according to a news agency link on the Sullivan page. Articles to watch and improve, therefore. Charles Matthews (talk) 14:22, 2 February 2010 (UTC) The Yau page is being actively edited, and some effort is going to be needed to ensure NPOV. Charles Matthews (talk) 16:23, 3 February 2010 (UTC) There have been large-scale additions of material that is not encyclopedic in tone. Please help out. This article is a BLP, and must adhere strictly to Verifiability and Neutrality policies. Charles Matthews (talk) 16:46, 4 February 2010 (UTC) ## Table of costs of operations in elliptic curves Table of costs of operations in elliptic curves has been prodded. It was written by someone pretty much wholly unaware of Wikipedia usage conventions. I suspect it can be cleaned up. Michael Hardy (talk) 07:46, 4 February 2010 (UTC) Unprodded, anyway. The material is indeed technical, but elliptic curve crypto is out there on websites with your credit card details. Charles Matthews (talk) 08:30, 4 February 2010 (UTC) One problem with the article as it stands is that without sources it is very difficult to verify the operational time-cost values given for each curve representation. They do not seem to follow in any obvious way from the definitions of the group operations for the respective curve representation. Gandalf61 (talk) 10:18, 4 February 2010 (UTC) The definition of cost in the table looks screwy. Inversion = 100 multiplications? Maybe that's true for some computer architecture somewhere, but surely that's not true for every computer architecture everywhere. Is this some sort of crypto-community heuristic? If so it deserves an explanation. Ozob (talk) 12:30, 4 February 2010 (UTC) This was created by the same person mentioned earlier, current research in cryptography. As I said earlier, notability is marginal and in this case the article is unreferenced and possibly OR. There are plenty of articles whose notability is certain and need to be worked on. To me, those have a higher priority. If you're going to work on an article that has no references then the you should add them before doing anything else. Making everything look nice isn't worth anything if you can't verify the information.--RDBury (talk) 15:32, 4 February 2010 (UTC) Certainly the article should be referenced. I have a little problem with your general attitude, though. I have referenced literally hundreds of articles in 2010. I happened to apply format to this one, while adding {{unreferenced}}. Where, exactly, is your problem with that? If you happen to be an authority on crypto I will of course defer to you on that matter. I think, as a matter of fact, I do not actually share your priorities in developing Wikipedia, since I have set a high store on creating content for the past six and half years rather than carping about it; but on some matters editors can agree to differ. Charles Matthews (talk) 15:53, 4 February 2010 (UTC) Perhaps my attitude was a bit overly critical. I'm just tired of seeing articles with dozens if not hundreds of edits and yet still no one has bothered to find references. Then, often when you read the article it looks like someone's vague recollections of a calculus class they took ten years ago rather than an encyclopedia article and it's clear that no one did any actual research for it. I would like this project to be something I can take pride in. So when I see a poorly written article with little useful information I tend it take it a bit personally, especially when that article is seen by hundreds of people a day. So fixing articles like that is, for me at least, what people should be spending time on. I've done my share of work on obscure subjects too, but they're ones I'm interested in and everyone needs some fun. As for spending most of my time carping, actually right now I'm spending most of my time of the Curve article which despite having been created eight years ago and being viewed by a couple hundred people a day, can still use a lot of work.--RDBury (talk) 17:16, 4 February 2010 (UTC) There's a survey of the field from a few years ago at http://eprint.iacr.org/2007/441.pdf. What is posted in the table may be from someone's unpublishable dissertation, or compiled from this and other things on the "Explicit-Formulas Database" at http://www.hyperelliptic.org/EFD/. That is the real issue. I've just left a note at Wikipedia talk:WikiProject Cryptography about it. The "Database" carries no license or copyright information, and one concern should be that some of the related curves articles borrow too much from it. Charles Matthews (talk) 19:13, 4 February 2010 (UTC) ## Quintuple Can any expert check out all the following: 1. The info at Number prefix#References about the words quadruple and quintuple 2. The info at Tuple#Origin of name 3. The discussion at Talk:Tuple that nobody but me and User:Cybercobra has been into I would like to note the disagreement about the origin of the word quintuple in the 2 articles. Georgia guy (talk) 21:47, 4 February 2010 (UTC) Fixed, I hope, from the OED and a Latin dictionary. Quintuple is not a mistake, it simply arose in the thirteenth century. Septentrionalis PMAnderson 05:37, 5 February 2010 (UTC) ## Mistake in Theorem? The article theorem says: Logically many theorems are of the form of an indicative conditional: if A, then B. Such a theorem does not state that B is always true, only that B must be true if A is true. In this case A is called the hypothesis of the theorem (note that "hypothesis" here is something very different from a conjecture) and B the conclusion (A and B can also be denoted the antecedent and consequent). The theorem "If n is an even natural number then n/2 is a natural number" is a typical example in which the hypothesis is that "n is an even natural number" and the conclusion is that "n/2 is also a natural number". I've the feeling there is subtle a mistake: the typical example is not in the form if A, then B, it's in the form for any x if A(x) then B(x), and this is true for the majority of the theorems. It would be rather strange to find a theorem which says if A, then B where A and B are closed formulas. What do you think?--Pokipsy76 (talk) 17:14, 3 February 2010 (UTC) This should probably be discussed at Talk:Theorem. You're right that it's unusual to have a theorem of the form "if A, then B" for sentences A and B -- this would be a conditional theorem. But if you let A be f(x) and B be g(x) where x is free in f and g, then "if A, then B" is a perfectly acceptable form. CRGreathouse (t | c) 19:44, 3 February 2010 (UTC) Yes but this happens only because of the convention to consider free variables as universally quantified.--Pokipsy76 (talk) 20:31, 3 February 2010 (UTC) It's more than convention, really; it's considered an axiom in some formal systems (e.g., it's Metamath's ax-gen). The intuition is that if you can prove f(x) without using x, then it's true regardless of which x you pick and so true for all x. CRGreathouse (t | c) 21:05, 3 February 2010 (UTC) Ok I think you are right, but don't you think that the text is potentially misleading? I say this because I recently had to do with people who were studying material implication and came to the conclusion that typical theorems of mathematics (of the form "A->B") were comparable to sentences "P->Q" where P and Q are any couple of true independent statements (and the wikipedia page theorem was cited in this context).--Pokipsy76 (talk) 09:08, 5 February 2010 (UTC) In ZF, one might say that if the axiom of choice holds, then such and such is true. This does not use any common variable "x". If "Q" is a true sentence and "P" is any meaningful sentence, then "P->Q" is true. It is just not particularly interesting or useful. JRSpriggs (talk) 02:41, 6 February 2010 (UTC) Sure, so what if we write «Logically many theorems are of the form of an indicative conditional: if A(x), then B(x), where x stands for a generic mathematical object of some kind.»? Too technical?--Pokipsy76 (talk) 09:12, 6 February 2010 (UTC) I think you have a point, Pokipsy76. But I'm not too keen on your current suggestion and I don't have a better wording. CRGreathouse (t | c) 03:29, 7 February 2010 (UTC) ## Project Redirects If there's no rule against project redirects, I think Wikiproject:Mathematics and Wikiproject:Math should be created as redirects to this project. I doubt there would be any controversy over those names being taken for aliases. LokiClock (talk) 14:07, 5 February 2010 (UTC) Creating new cross-namespace redirects is generally disapproved of at the moment. Only three wikiprojects have such redirects, so it's not like people are going to expect them and try to use them. We have redirects at WP:WPM, WP:WPMATH and WP:Mathematics, and WP:MATH and WP:Math point to Help:Displaying a formula, which has a hatnote. I think that's enough. Algebraist 16:00, 5 February 2010 (UTC) Agree. Paul August 16:29, 5 February 2010 (UTC) Maybe what the original poster meant was Wikipedia:Wikiproject Mathematics and Wikipedia:Wikiproject Math? Michael Hardy (talk) 23:04, 5 February 2010 (UTC) No, I meant what I indicated. I misread the group name as Wikiproject:Wikiproject Mathematics, which would of course be a silly name. LokiClock (talk) 17:45, 6 February 2010 (UTC) ## Possible improvements of [itex]: links I have some thoughts how to improve rendering of mathematical formulae in Wikipedia. First, to allow a link from a mathematical symbol inside a formula, something like that [itex]\link{smooth function}{C^\infty}(\link{sphere}{S^2},\link{real numbers}{\mathbb R})$


will produce: C(S2) .
I know, it is extremely difficult for rasterized output, but it would be helpful even if this will work with HTML and MathML output.

It would be also useful if any -formula had internal link to Mathematical notation article by default, unless this formula contains an internal link, the link turned off by special tag parameter or in user preferences. Such link is similar to {{IPA}} for phonetic transcription. The style of the link on (or inside) a formula must be not underlined, bordered or so, indeed. The article “mathematical notation” in this case should contain much more explanations, like a corresponding article in ru.wiki which is currently far from completeness, though. Incnis Mrsi (talk) 22:00, 6 February 2010 (UTC) There is another possibility, alternative to linking to “mathematical notation” directly. When clicking to a formula, run a popup (JavaScript or so) trying to grammatically parse the formula and give to a user some DHTML output with necessary links. Incnis Mrsi (talk) 22:22, 6 February 2010 (UTC) As you've noted it will be difficult to do this with rasterised images, and difficult to know when that's needed as an arcane combination of browser, user settings and the complexity of the math determines what gets rasterised. But I'd also question how often you want to do it. E.g. in the example the choices over what and where to link to are to some extent arbitrary. Why not link to infinity for example. More generally if you feel the need to explain notation it should be done separately, e.g. "where C is a smooth function...". The elements of a formula are often small making it difficult to spot links, to see where one ends and another begins, and for some users (e.g. when using a touch-pad or screen) difficult to precisely place the cursor to select them. Unless it's the whole formula I'd say it's a bad idea, and even the whole formula might be better done with e.g. a text link after. --JohnBlackburnewordsdeeds 22:36, 6 February 2010 (UTC) It is already possible to link the whole formula (even though it does not look like a link on the first sight): $C^\infty$. — Emil J. 12:13, 8 February 2010 (UTC) I think it is better to avoid links within formulas, and just explain the symbols in the surrounding text. On one hand, English is very flexible for explaining exactly what is happening in each article. And we have a lot of experience explaining formulas in print, where there are no hyperlinks. On the other hand, I am afraid of people going around adding "missing" links that are of little value or are even misleading. For example, I might see this in the context of Hindman's theorem: Color the elements of $2^{<\infty}$ with k colors It would be tempting, but very wrong, to link that infinity sign to an article on infinity. (What the symbolism means is to color every finite sequence of 0s and 1s). — Carl (CBM · talk) 13:00, 8 February 2010 (UTC) There's another reason as well to make the link and the description in the surrounding text rather than in the formula: getting changes made to the underlying Wiki code and propagated to Wikipedia can be very difficult, whereas links in surrounding text are available now. —David Eppstein (talk) 15:59, 8 February 2010 (UTC) ## Wikipedia:Articles for deletion/George Kayatta I'm not really sure this concerns the mathematics WikiProject. Until recently the article said that this alleged genius has contributed to mathematics (among many other things). Now it says he claims to have contributed to mathematics. Underwood Dudley wrote a book about mathematical crackpots in which he devoted a whole chapter to this guy—hence some asertiosn of notability. The discussion looks as if it may be heading for a "no consensus" outcome, the immediate result of which is that it is kept rather than deleted. (I'm not even sure whether it should be kept, but if it is, I might try to improve it—in particular see if one can document some of the claims.) Michael Hardy (talk) 18:37, 7 February 2010 (UTC) Nitpick: the book devotes a whole chapter to megalomaniacs, of which Kayatta is only one example out of 3-4. But Kayatta is the only one explicitly named at the end of the book, while the others are referred to by initials only. (In the chapter Kayatta is referred to as G. K. or just K.; at the end his name is called out.) CRGreathouse (t | c) 21:44, 7 February 2010 (UTC) ## Dimensionality again The names in Template:Polytopes, and the general expansion of higher-dimensionality articles, needs some help. (Is there a WikiProject Geometry? That might be a better place to put that.) In regard Template:Polytopes, I suggest removing the 1-polytope entry, and writing the rest something like: 2 (Polygon){{.}}3 (Polyhedron){{.}}4 (Polychoron}{{.}}5{{.}}6{{.}}7{{.}}8{{.}}9{{.}}10 My proposal for much of the dimensionality articles: Most of the articles are now at "en-dimensional space". (For example, when n=5, by "en-dimensional space" I mean five-dimensional space. 1. Split out "enth dimension" for ideas referring to that dimension in common usage; much of fourth dimension really is of that form. 2. Move "en-dimensional space" to "n-dimensional space". 3. Move those parts of "en-dimensional space" about polytopes to "n-polytope", and summarize in the main article. 4. Move much of those parts of "en-dimensional space" which do not depend on the value of n to n-dimensional space there, and possibly summarize. 5. Move those parts of "n-polytope" which do not depend on the value of n to polytope, and possibly summarize. There may be other "obvious" changes which should be made, but I don't want to revert the prolific editor 4, without some consensus. — Arthur Rubin (talk) 17:23, 8 February 2010 (UTC) I jumped in, since I added most of the content of the n-polytope articles. I removing the dimensional names from the template above 3, and removing 1-polytope entirely. Most of my work has been related to uniform polytopes, and I've moved content of these for 4,5,6 to separate articles. The dimensional specifies of the uniform polytopes are most apparent by symmetry classes, while other contexts specifics by dimension are not clear to me. Tom Ruen (talk) 03:48, 9 February 2010 (UTC) ## Use of Matlab code in articles This has come up here, but I've noticed it on other pages. Should Matlab code be used in maths articles? Few people have access to the program because of its price, and judging by the sample code in simplex it's of little help to those who don't use Matlab, as the syntax is unlike other programming languages but also unlike symbolic maths. It obviously is used by some people otherwise it would not have been added, but I suspect it's only used by a minority of editors and an even smaller fraction of readers. Should Matlab code be used at all? Is there anything it can be replaced with, such as a less proprietary language, that more people are familiar with or have access to? I think the answer may be different in different cases, i.e. if Matlab has been used because of it's mathematical strengths it might be difficult to replace. But if as in simplex it is just being used to manipulate numbers and vectors then any modern programming language could be used, or the article could just give a clear explanation which any technically minded reader could implement.--JohnBlackburnewordsdeeds 10:35, 2 February 2010 (UTC) I'm very unkeen on programming language code being stuck in, I'd prefer a longer winded pseudo code myself. It shouldn't be too hard to turn the code into an english description with indenting to group bits. Dmcq (talk) 11:06, 2 February 2010 (UTC) I think the article in question already has descriptions, so those could be improved and the code removed. I am generally not in favor of adding source code to "pure" articles such as simplex. For example, I would not like to see source code in group (mathematics) even though there are lots of computations one could do for groups. For a few articles on the subject of computability, or for articles on numerical methods, pseudocode can be appropriate, though. — Carl (CBM · talk) 11:23, 2 February 2010 (UTC) Second that. It's hard to see, useful or not, how actual code isn't either OR or COPYVIO. Pseudocode describes the algorithm and the readers can do their own implementation in whatever language they wish. Plus, no matter how readable a computer language is, if you don't know it then interpreting the code is going to be a matter of guesswork. The only time I can see that code should be used is for example code for an article about the language itself. Btw, if there is any kind of consensus on this issue can we add it to WP:MOSMATH so result won't disappear into the archives? This has appeared before at Wikipedia:Village pump (miscellaneous)/Archive 19#Source code written by editors. --RDBury (talk) 11:42, 2 February 2010 (UTC) There's no such thing as copyvio of math formulas, regardless of what formal language is used to represent them. that being said, i think the c (programming language) would be more universal. though i understand that, not being an array programming language, some things would be more complex. also its math function library ("math.h") probably isn't as extensive as matlab's. Kevin Baastalk 16:39, 2 February 2010 (UTC) I agree, I have no problem with code as OR or COPYVIO. Within reason it's just a way of presenting an example, which is allowed and encouraged to make articles more accessible. The problem is coming up with a language that's suitable. In theory you could do everything in C, but even arrays are a lot of work in C. But any other language is likely to be less familiar and/or less standardised, especially if it uses specialised math or plotting techniques. I've fixed one of the instances in simplex by rewriting it so the sample is much easier to follow and removing the Matlab code altogether. There's another chunk in there which I've left in as it's in an area I'm less familiar with, though I've added some syntax colouring which at least makes it more readable. The thing to use seems to be: <syntaxhighlight lang="matlab"> ... </syntaxhighlight> It would be good to do this to any Matlab (or any other code) samples so they are easier for especially people not familiar with Matlab to follow, if it cannot be removed or replaced straight away. --JohnBlackburnewordsdeeds 17:30, 2 February 2010 (UTC) Code is not the same as a formula. Look at the Tower of Hanoi article for example. It has long sections of code in several languages which are either take directly from a book or magazine (COPYVIO) or an editor wrote the code in which case it can't be verified (OR). Plus, I don't know the languages used so a good chunk of the article is complete gibberish to me; it's hard to argue that it's helping the make the article more understandable. Even if code were a good idea, C is a bad choice because it tends to be terse and unreadable. For example the article I mentioned uses "the mth move is from peg (m&m-1)%3 to peg ((m|m-1)+1)%3". I was a C programmer fo 2 years and I have a hard time understanding it; is a reader who doesn't know C supposed to make any sense at all from it? Encyclopedia articles are supposed be accessible to as wide an audience as possible, yet here we have an article about a children's toy that requires a degree in computer science to understand. If you make the claim that is not COPYVIO or OR then give an example where it isn't and if you think it may make an article easier to understand then give an example where it does.--RDBury (talk) 18:45, 2 February 2010 (UTC) (ec) The COPYVIO discussion was covered by RDBury above, better than I did in my attempted comment. . As for Matlab, I agree that, where it doesn't reflect standard mathematical notation, it probably shouldn't be in articles, except on Matlab itself or Matlab packages. (I say this as someone who has used Matlab for over 14 years.) — Arthur Rubin (talk) 18:54, 2 February 2010 (UTC) I could write a program in any computer language to generate all the possible programs in all known computer languages (or ones that i know at least) that do the tower of hanoi, and i'm sure many of them would be exactly the same as are in a book or magazine. does that mean my computer program should go to jail / pay a fine? Fine, you know what, I'll make up my own formal language and state it there. No difference. exactly my point. and you know what? my first attempt at writting a tower of hanoi program would probably turn out to be exactly the same as in a book somewhere. just like my first attempt at an algorithm to add two numbers would. see the problem there? i'm sure we could go over the differences between algorithms and formulas, but none of them would be relevant. But as mentioned, this topic was covered above and probably ad nasuem elsewhere in wikipedia. so let us not digress. the issue is: what formal language should we write our ironically simultaneously both OR and COPYVIOs in? Kevin Baastalk 19:05, 2 February 2010 (UTC) A text to be understood by a man should be written in an informal language. A formal language is for a text intended for a computer. (Among programming languages I prefer Python, but this is irrelevant.) You may object: math formulas are a formal language, but intended for a man. Well, we do use formulas in WP, but only as a rather short insertions (half a line, sometimes several lines, but not more). An algorithm should not be longer in a WP article, I think so; otherwise, its informal idea should be written. Boris Tsirelson (talk) 20:31, 2 February 2010 (UTC) I think there is occasionally a place for programs. Sometimes they're good for making things unambiguous -- I've used program listings for this a great many times. But I don't generally favor their use, especially not in a proprietary language like Matlab. CRGreathouse (t | c) 04:51, 3 February 2010 (UTC) Really? Which language do you use? Can we see some examples? Boris Tsirelson (talk) 07:16, 3 February 2010 (UTC) I also think that sometimes programs make it easier to understand things. Recently I wanted to understand what the Floyd-Warshall algorithm does, and I just looked at Floyd–Warshall_algorithm#Pseudocode for 30 seconds and it was clear to me. Reading the text was too slow. But I also agree that there are many cases where I would prefer some math + English explanation instead of pseudocode, like for Strassen's algorithm. --Robin (talk) 13:48, 3 February 2010 (UTC) If by "programs" you mean pseudocode then I have no objections. Pseudocode is not worse (nor better) than math formulas. I object to a code, just because it fits computers, not humans. Pseudocode fits humans. Well, not all humans; but the same holds for math formulas. But if a pseudocode is long and complicated, then it is as bad for WP as a long and complicated mathematical proof. Boris Tsirelson (talk) 15:29, 3 February 2010 (UTC) Pseudocode is subject to the same restrictions as "normal" code - namely, it has to be formally rigorous. Thus, psuedocode can be just as complex as "real" code, and vice-versa converse/inverse what have you. I.e. a compiler / interpretor can be written for any "pseudo-code", thus making it no longer "psuedo-code"; thus, the only real difference between "pseudo-code" and "real code" is whether a compiler / interpreter has been written for it. Either can be as "fitting" or "un-fitting" for humans as you like, subject only to the restriction of formal rigour. Whether we use pseudocode or real code comes down to a question of whether we invent our own formally rigourous language that no one is familiar with and a compiler hasn't been written for, or we use a pre-established one that many people are familiar with and can be compiled and tested readily. Kevin Baastalk 15:49, 3 February 2010 (UTC) If you require pseudocode to be formal then I object to it. But I believe it can be interpreted differently. I do not insist on the word "pseudocode". Boris Tsirelson (talk) 17:44, 3 February 2010 (UTC) The whole point of it is to be formally rigorous. If that was not the goal, then a paragraph of plain english would work much better. As was pointed out above, a programmer like myself might come to an article, and read "bla bla bla bla", then get fed up and skip to the code/pseudocode and in 30 seconds be like "Oh, i get it." Now if the code wasn't formally rigorous, instead they'd be like "well that doesn't make any sense." or "now that's still rather ambiguous." If you want plain english then just use plain english. If you want to be precise then you better d@mn well be precise, otherwise you're just going to add confusion. Kevin Baastalk 17:50, 3 February 2010 (UTC) If we were going to be formally rigorous, we should use a well-established and widely understood formalism: a long-established - and preferably open-source - computer language would be one possibility, but Principia Mathematica would be better. But I don't see why we should; our sources aren't - they are rigorous enough that the details can be left to the reader. Septentrionalis PMAnderson 20:08, 3 February 2010 (UTC) ────────────────────────────────────────────────────────────────────────────────────────────────────That's the great thing about pseudocode: It's formal enough to be like a programming language, and yet informal enough that no one has to study its syntax or construction. Just knowing English and any other programming language allows you to understand pseudocode. --Robin (talk) 20:20, 3 February 2010 (UTC) Yes, this is my idea of pseudocode, different from that of Kevin Baas. Boris Tsirelson (talk) 20:52, 3 February 2010 (UTC) That is actually the same as my idea. My point is that if "It's formal enough to be like a programming language" then it's formal enough to be compiled/interpreted by a computer program to something that can be processed by a computer. And if it isn't, well, then it's not "formal enough to be like a programming language". Kevin Baastalk 17:32, 10 February 2010 (UTC) I am fine with an implementation in a particularly suitable language, for example using a common array programming language where optimal, but only when pseudocode is first given. I am personally greatly in favor of pseudocode algorithms in general. In mathematics, sometimes the abstract terminology keeps you from realizing what those things could be. I didn't understand what a Fourier transform was supposed to be doing until pseudocode made "bins" into quantized data. To restate from the Simplex talk, I feel that using a particular implementation exclusively represents a POV, not to mention, as with the OP, I as a non-MATLAB programmer find MATLAB code incomprehensible. What I do understand I can't rely on, because what I fail to notice or understand is likely to completely change the logical outcome of the program. Using a proprietary language in particular induces an economic factor. Would you write an article that requires the reader to follow along with a textbook? No, because then to use the article they have to buy that textbook. LokiClock (talk) 14:58, 4 February 2010 (UTC) I've put forward some ideas on this at WT:MSM#Source code and pseudocode to see if we can get something done about it.--JohnBlackburnewordsdeeds 15:47, 10 February 2010 (UTC) ## Superslow process Could an interested and knowledgeable editor please take a look at Superslow process and Vladimir Miklyukov? The creator of both is User:SobakaKachalova, who happens to be Miklyukov's daughter. She doesn't like the tags currently on Miklyukov's article, so she asked for and received a 3rd opinion. She didn't like that either (she said "it did not work since the editors do not have interests in mathematics"). She currently has a {{helpme}} tag on her talk page, and I think she could use a hand. Just an FYI, and probably irrelevant, but it all smells fishy to me... WorldCat has no records of the cited ISBNs; Miklyukov's last book (self-published in 2008 through Xlibris) is in no libraries (per OCLC 290444522 and OCLC 290444525); and the biographical references are to sources like Marquis Who's Who (which is not a reliable source). Thanks! Dori ❦ (TalkContribsReview) ❦ 00:16, 9 February 2010 (UTC) Miklyukov appears, at first blush, to be notable -- though of course negative findings on the books might change my opinion. I have severe doubts as to the notability/appropriateness of Superslow process, though. In any case both have severe format/grammar/cleanup issues. CRGreathouse (t | c) 21:19, 10 February 2010 (UTC) Just so it doesn't look as if CRGreathouse is alone: I agree with these concerns. Hans Adler 01:51, 11 February 2010 (UTC) ## Definition without meshes I've just done some editing on Riemann–Stieltjes integral. I've tried to state the definition in a way that does not mention "meshes" of partitions, since I take the Riemann–Stieltjes integral to be a limit of a net. Here's how the "Definition" section now reads: The Riemann–Stieltjes integral of a real-valued function f of a real variable with respect to a real function g is denoted by $\int_a^b f(x) \, dg(x)$ and defined to be the limit, as the partition $P=\{ a = x_0 < x_1 < \cdots < x_n = b\}$ of the interval [ab] becomes finer, of the approximating sum $S(P,f,g) = \sum_{i=0}^{n-1} f(c_i)(g(x_{i+1})-g(x_i))$ where ci is in the i-th subinterval [xixi+1]. The two functions f and g are respectively called the integrand and the integrator. The "limit" A (the value of the Riemann–Stieltjes integral) is a number such that for every ε > 0 there exists a partition Pε such that for every partition P that refines the partition Pε (i.e. Pε ⊆ P), and for every choice of points ci in [xixi+1], $|S(P,f,g)-A| < \varepsilon. \,$ So improve it if you can. Michael Hardy (talk) 17:34, 9 February 2010 (UTC) Sorry Michael, I reverted your edit. Indeed, the classical definition of the RS integral does use meshes rather than refinements. This is actually not equivalent to the latter generalized definition (a generalization usually attributed to Pollard, but often with Moore and Smith's name attached to it as well because of the connection with nets). McShane has an article that addresses exactly this point about the two different integrals, quite lucidly if I recall. The other references in the article also address this point, especially that by Hildebrant. Sławomir Biały (talk) 18:03, 10 February 2010 (UTC) ## Gaussian minus exponential distribution Gaussian minus exponential distribution needs work. In particular, it's an orphan: other pages should link to it. Michael Hardy (talk) 03:14, 10 February 2010 (UTC) I turned up no hits in Google books and 7 in Google web, most of which point to the Wikipedia article. My conclusion is the subject isn't notable and the only work that should be done is an AfD.--RDBury (talk) 16:15, 10 February 2010 (UTC) This article by Carr & Madan from the Journal of Computational Finance, using the term Gauss minus exponential, and appears to be the main source. This item, apparently a master's thesis at Imperial College in London, uses the term Gaussian minus Exponential and cites the paper by Carr & Madan. "Normal plus exponential" appears more frequently and may be mathematically the same thing; apparently it's applied in biochemistry and in psychology. Michael Hardy (talk) 17:19, 10 February 2010 (UTC) ## Zeno's paradoxes See Wikipedia:Arbitration/Requests/Case#Zeno.27s_paradoxes, which is entirely a contents issue as far as I can tell. Pcap ping 16:30, 11 February 2010 (UTC) ## Quasipositive function This article has been proposed for deletion. If you have knowledge of the subject kindly take a look to see if it is worth salvaging. -Arb. (talk) 23:34, 12 February 2010 (UTC) I speedied it - "definition" didn't define anything. Charles Matthews (talk) 08:51, 13 February 2010 (UTC) ## Positive definiteness - disambig? I had marked Positive definiteness as a disambiguation page, but it was reverted. Could someone else look at that? — Carl (CBM · talk) 19:30, 13 February 2010 (UTC) I think I see the reverting user's point of view. It might be nice to have a page about the concept of positive definiteness itself, and then link to its usage in mathematics. As far as I understand, the usage of the phrase conveys a similar meaning in all applications. Alternately, the disambiguation page could just explain the idea of positive definiteness in 2 lines, and then link to the various uses in mathematics. --Robin (talk) 20:05, 13 February 2010 (UTC) The article doesn't really work as anything but a dab page. Generally, though I know someone will think of an exception, adjectives and abstract nouns don't make good subjects for articles.--RDBury (talk) 21:36, 13 February 2010 (UTC) ## Movable cellular automaton As Michael Hardy would say, this article is a mess. But before asking people to get to work on it I would note that notability is marginal. I did not turn up any secondary sources for the subject but I did turn up a plethora of primary sources from a variety of disciplines so maybe the notability criteria could be stretched to include this. The article itself seems to be the brainchild of a something called "MCA lab", presumably pictured at the bottom of the article. There is a huge amount of material in the article but with no references given so impossible to say how much of the material is original research. At the least, there are huge COI issues with the authors writing about their own work. If there is salvageable material here then it should probably be saved and turned to the kernel for a better article, but if a complete rewrite is needed then I'd say it would be better to delete for now and recreate it if/when secondary sources appear.--RDBury (talk) 03:31, 14 February 2010 (UTC) Note: The article seems to have been developed concurrently in both English and Russian, click the link next to the article to see the Russian version.--RDBury (talk) 03:41, 14 February 2010 (UTC) ## Help:Displaying a formula Help:Displaying a formula seems to have a lot of focus on how WP works technically and doesn't seem to be too clear. These details are probably unecessary ( or could be put in a technical paragraph at the end ) and seem to be a left oer of a design spec rather than a help page. I have no idea how much of the information is relevant or useful, so could do with some pointers on what to do with this page, many thanks --Lee∴V (talkcontribs) 15:32, 10 February 2010 (UTC) (Wikipedia:Help Project) If you're talking about the TeX vs HTML section then I think it's needed. The current TeX implementation is a bit of a kludge since it sometimes renders a formula as an image and sometimes as html and these can appear very different on a browser. Unfortunately, editors need to know about what's going on to be able to control the appearance of the formulas they type in. Someday, though I don't think it's going to happen soon, the wiki TeX renderer will be smart enough to match the size of a formula to the surrounding text and these technical details won't be necessary, but until then editors will need to know the difference between x and $x\,.$--RDBury (talk) 16:02, 10 February 2010 (UTC) Hmmm, maybe we should put your words as an intro to the technical bit, they make more sense than the whoe paragraph! keep fingers crossed for advancements - I've seen hints that WYSIWYG editing is getting closer so miracles can happen! --Lee∴V (talkcontribs) 19:26, 10 February 2010 (UTC) Help:Displaying a formula is very relevant and useful for editors of Wikipedia's mathematics and science articles. It is the essential guide to Wiki's implementation of LaTEX, and a "must read" if you are editing any Wikipedia article containing mathematical expressions. I use it for reference at least once a week. Gandalf61 (talk) 16:14, 10 February 2010 (UTC) Ah - I understand the page itself is useful, was just wondering about its presentation --Lee∴V (talkcontribs) 19:26, 10 February 2010 (UTC) I use Help:Displaying a formula frequently when I forget how to generate a particular symbol. I scan it for the symbol and look at the sequence of characters which generate it. Please do not remove any such information from the article. Thank you. JRSpriggs (talk) 09:26, 12 February 2010 (UTC) Don't worry - I have no plans to remove it, just checking bits of it weren't a leftover from being transfered from Mediawiki help... Lee∴V (talkcontribs) 02:18, 15 February 2010 (UTC) ## Polynomially reflexive space Dear Wikimathematicians, the above article is being considered for deletion. 131.211.113.1 (talk) 22:46, 14 February 2010 (UTC) ## Recent changes to Interpolation, Lagrange polynomial, Polynomial interpolation Can someone please have a look at these articles and the discussion here. I removed some changes which seemed totally out of place but User:MathFacts has just reinstated them with slight adjustments in position. It's not particularly my area of expertise so I don't recognise the formulae he's trying to insert, but they certainly don't belong in those articles in their current forms.--JohnBlackburnewordsdeeds 18:58, 17 February 2010 (UTC) I agree, they should be removed. One wonders why this editor is insistent on plastering the same content over multiple articles. I went ahead and removed them. Sławomir Biały (talk) 19:52, 17 February 2010 (UTC) Dont you agree that interpolation formulas should be in articles about interpolation? Is it unnatural somewhat? Should not Lagrange interpolation formula be in article about Lagrange interpolation?--MathFacts (talk) 22:43, 17 February 2010 (UTC) I would want to see a proper citation for those formulae showing people think they are worth writing about rather than just something you thought were useful and you worked out yourself. Dmcq (talk) 22:57, 17 February 2010 (UTC) Not to mention the fact that there are already more typical formulas in the Lagrange interpolation article. Sławomir Biały (talk) 23:09, 17 February 2010 (UTC) See my talk page.--MathFacts (talk) 23:57, 17 February 2010 (UTC) ## Direct sum - another DAB outreach request Hi all, I was wondering if we could get some (more) help from this project. I'm working on the Wikipedia:Disambiguation pages with links project, and one of the most-linked dabs is Direct sum. This used to be a redirect to Direct sum of modules, but in December it was converted into a disambig, and now it has over 100 links that need fixing. I'm sure most of these should be pointing to Direct sum of modules, but I don't feel qualified to make that call. Could someone give us some guidance? The list of links can be found here. Thanks! --JaGatalk 09:30, 17 February 2010 (UTC) I can take a look at it later today. One problem, though, is that some of these should really target articles that don't yet exist: e.g., the occurrence in Representation of a Lie group should target Direct sum of representations, and the occurrence in Reductive Lie algebra should target Direct sum of Lie algebras. RobHar (talk) 15:02, 17 February 2010 (UTC) Let's change them to those redlinks, then, and add them to Wikipedia:Requested articles/Mathematics. CRGreathouse (t | c) 16:43, 17 February 2010 (UTC) The definition of the direct sum of two Lie algebras is given at direct sum of modules#Direct sum of algebras, which is where I've been linking to in that case. There's no real information there though. Algebraist 17:03, 17 February 2010 (UTC) I would have preferred linking to Direct sum of Lie algebras, redirecting that to Direct sum of modules#Direct sum of algebras, and marking it with {{R to section}} and {{R with possibilities}}. CRGreathouse (t | c) 19:41, 17 February 2010 (UTC) Looking at some of the articles that link to Direct sum, it looks to me like "Direct sum" should be an article, not a dab. For example, the first five articles listed here are all referring to general notions of the direct sum, not any specific direct sum (e.g. the article Limit (category theory) mentions that colimits generalize constructions such as coproducts and direct sums). I'd suggest turning "Direct sum" back into an article (there would of course still be many links to change). Thoughts? RobHar (talk) 17:54, 17 February 2010 (UTC) The fact that the first few are all references to direct sum in a general sense is an artefact of my fixing effort: I retargetted the others, and I was working from the top. I think most of the incoming links are specifically about the case of vector spaces/modules/algebras. Still, I think there's probably enough material in the general concept for an article, which could also briefly cover any specific uses that don't yet have articles. Algebraist 18:59, 17 February 2010 (UTC) I'm going to turn "direct sum" into an article, approximately following the template of Direct product, and go through the links. RobHar (talk) I also think "direct sum" needs its own article. Direct sums are coproducts in abelian (or additive or preadditive) categories and this is a framework into which specific examples fit. Geometry guy 20:57, 17 February 2010 (UTC) Alright, I got through all the links and disambiguated them. The article direct sum still needs some work though. RobHar (talk) 04:06, 18 February 2010 (UTC) Thanks so much for the help, everyone. It is greatly appreciated. --JaGatalk 09:05, 18 February 2010 (UTC) ## \mathrm is not the same as \text (nor is \mbox) In Baker's map, I found this: $S_\mathrm{baker-folded}(x, y) = \begin{cases} (2x, y/2) & \mbox{for } 0 \le x < \frac{1}{2} \\ (2-2x, 1-y/2) & \mbox{for } \frac{1}{2} \le x < 1 \end{cases}$ I changed it to this: $S_\text{baker-folded}(x, y) = \begin{cases} (2x, y/2) & \text{for } 0 \le x < \frac{1}{2} \\ (2-2x, 1-y/2) & \text{for } \frac{1}{2} \le x < 1 \end{cases}$ The first uses \mathrm{baker-folded}; the second uses \text{baker-folded}. When \mathrm is used, the hyphen becomes a minus sign; when \text is used, it remains a hyphen. The first uses \mbox{for }; the second uses \text{for }. In some contexts, those look much more different from each other than in the example above. For example, contrast \min_\mbox{abcd} with \min_\text{abcd}: \begin{align} \min_\mbox{abcd} \\[8pt] \min_\text{abcd} \end{align} The purpose of \mbox is to prevent line-breaks when TeX is used in the usual way as opposed to the way it's used within Wikipedia. It shouldn't be used as a substitute for \text. Michael Hardy (talk) 15:57, 18 February 2010 (UTC) Indeed. I guess the problem is that \text comes from AMSLaTeX (amsmath) rather than base LaTeX, therefore some people are not familiar with it.—Emil J. 16:03, 18 February 2010 (UTC) I don't think \text was always supported by Wikipedia's implementation of TeX (correct me if I'm wrong). So there might be some legacy \mathrms lying around. Sławomir Biały (talk) 00:08, 19 February 2010 (UTC) I seem to remember it that way too. But I'm not sure all of them are from the time when we didn't have \text. Maybe when we got \text, some people never found out. Michael Hardy (talk) 02:35, 19 February 2010 (UTC) ## ANI notice... about this whole WikiProject Some sort of group sanctions are requested. See Wikipedia:ANI#Harassment. Pcap ping 01:37, 17 February 2010 (UTC) Despite the request for action against this WikiProject (!), we're really not a party to this discussion. The exception is User:Hans Adler who seems to be accused of sockpuppetry and harassment; I will notify him on his Talk page. CRGreathouse (t | c) 01:57, 17 February 2010 (UTC) Well, ANI etiquette requires a notification. Since he asked for a 24hr block of all members of this project, it seemed appropriate to post here. The request was dismissed as silly, so this should probably just be moved to archives to lower the drama. Pcap ping 04:04, 17 February 2010 (UTC) I was about to post a similar note asking if anyone had some constructive suggestions on ways to move things forward. -- Banjeboi 10:30, 17 February 2010 (UTC) Last time this was discussed here, there was an agreement to do something, but we couldn't agree what exactly. There was split opinion between a RfC/U, formal mediation, or more informal mediation by User:Charles Matthews. Eventually, nothing happened. Pcap ping 23:40, 17 February 2010 (UTC) An ANI notice on the whole project! I guess it shows some imagination. Can I suggest also he use WP:BLP to stop references to his previous excursions being brought up, and WP:COI and WP:POV be used to prevent anyone with a maths degree editing any maths articles ;-) Dmcq (talk) 23:53, 17 February 2010 (UTC) As long as we understand that it is not POV when people from different academic disciples contribute to articles. I am wrongly accused by members of this project of POV all the time --for legitimate subject matter. So I am glad to see that you agree with me that interdisciplinary coverage is not POV. Now lets see if the members respect that.Greg Bard (talk) 19:13, 18 February 2010 (UTC) Absolutely everyone agrees that well informed interdisciplinary coverage is a good thing. But it is impossible to see as serious the suggestion that each of the members of this project be blocked! It simply looks like disruption and grandstanding. Paul August 13:38, 19 February 2010 (UTC) Ordinarily I would agree with you. I am pretty well known by my friends as very anti-corporatism in general. This is to say that I am against holding groups to have rights or privileges beyond individuals. I am against corporate personhood, in favor of abolishing the US Senate, I Decline to state, rather than support a political party, etcetera, etcetera, etcetera. Only this group, and the behavior of its members has risen to a level to where I would scrap a good principle, in order to deal with the pragmatic reality. I think if there were consequences for the high drama it would end. In any case, the members shouldn't concern themselves with the possibility of sanctions, but rather that they are being brought up. It reflects on the group. I don't know if anyone has a sense of this at all. But as a matter of civility, decency, leadership, etcetera, you should. Greg Bard (talk) 23:56, 20 February 2010 (UTC) Well, at least you know your principles and stick to them, unless something this important comes up. CRGreathouse (t | c) 00:30, 21 February 2010 (UTC) Absolutely! At some point you may have to spank the child, and not be held hostage by the abusers. I do, in fact, believe that collaborating civilly is very important, more so than your groups' play time.Greg Bard (talk) 01:59, 21 February 2010 (UTC) Because you are the parent and WikiProject Mathematics is your misbehaving child? And it needs to be punished for the action of an IP user not apparently related in any way to this project? Seriously, Greg... drop the stick and back slowly away from the horse carcass. CRGreathouse (t | c) 02:30, 21 February 2010 (UTC) WP:BEANS. Pcap ping 18:56, 18 February 2010 (UTC) It's been archived to Wikipedia:Administrators' noticeboard/IncidentArchive597#Harassment. I think we can let the matter drop now. CRGreathouse (t | c) 15:43, 19 February 2010 (UTC) If you've been following it you might like this video of cat herding. Shows it's possible :) Dmcq (talk) 17:17, 19 February 2010 (UTC) ## Could someone check my changes to Homogeneous differential equation, please? I've presented the whole intro to the homogeneous differential equation article using a more general formulation that makes the link to homogeneous functions clearer, rather than just taking the special case of f(x,y) = F(y/x), which only covers the case of homogeneous differential equations of degree 0. I hope that this is both more elegant and more general than the previous text, and provides a better lead-in to the second example lower down the article; in particular it makes clear in advance what "degree" means in this context, which is otherwise just thrown in without explanation. However, my maths education was a very long time ago: can people here please check my changes? -- The Anome (talk) 03:52, 17 February 2010 (UTC) The original definition seems be more in line with that given in MathWorld which, sad to say, seems to be the only valid reference. Do you have a reference for the definition you added?--RDBury (talk) 01:22, 18 February 2010 (UTC) No, just vivid memories of long-past math tutorials. A quick Googling finds this Cliff's Notes page, which appears compatible with the new treatment, albeit phrased in termos of differentials. -- The Anome (talk) 02:20, 19 February 2010 (UTC) Actually, that reference is more compatible with the old treatment. (For them, M and N must have the same degree, so F=M/N must have degree zero.) But, at any rate, I have added Olver as a reference to the article which supports the new treatment. While I trust that he knows his business quite well, it would be better to have a more authoritative source on differential equations as such. Sławomir Biały (talk) 02:31, 19 February 2010 (UTC) This is puzzling. There seem to be two different definitions in play; the first being the more general one, and the second the special case where degree=0. Most references discuss the second case, and only a few discuss the first, generally in the context of showing the standard method of solution by change of variables. However, since the degree=0 case is a subset of the general case, references supporting the special case don't invalidate the general case. I'll havbe to do some more searching in the print literature. -- The Anome (talk) 13:47, 20 February 2010 (UTC) In the meantime, I've wound the definition back to the previous, more restrictive case, and removed the whole second half of the article, which implicitly used the second, more general definition. -- The Anome (talk) 14:21, 20 February 2010 (UTC) That seems like overkill to me: I'm happy with either version (see my comment at the very end of this thread). But I agree with RDBury's original sentiment that more solid references are needed either way it goes. Sławomir Biały (talk) 14:41, 20 February 2010 (UTC) I think the new definition is wrong (well, at any rate, not what I would call a homogeneous differential equation): dx and dy should also carry weight one, in which case the old definition is correct, the right-hand side must have homogeneity zero. It's probably more intuitive to think of it in differential form as $f(x,y) dx + g(x,y) dy =0$ with f, g homogeneous functions. Sławomir Biały (talk) 01:54, 18 February 2010 (UTC) I just looked this up, and apparently I stand corrected. The more general definition is actually classically known as homogeneous. I don't have a very authoritative source, but Olver's Equivalence, Invariants, and Symmetry does have a discussion of homogeneous equations from this point of view. I will add it to the article. Sławomir Biały (talk) 13:40, 18 February 2010 (UTC) ## List of Italian mathematicians Hi. Plenty of missing articles to start! See Italian wikipedia biography equivalent... ‡ Himalayan ‡ ΨMonastery 18:04, 18 February 2010 (UTC) Could you replace "(matematico)"? Charles Matthews (talk) 13:58, 20 February 2010 (UTC) ## Naperian logarithm article Is Napierian logarithm accurate? Is it a joke? Based on the current content, I would believe either one. — Carl (CBM · talk) 04:12, 19 February 2010 (UTC) I added some references. It appears to check out. —David Eppstein (talk) 05:02, 19 February 2010 (UTC) The DNB article on Napier explains the history, namely that Henry Briggs of Gresham College saw the advantage of the change to a more standard linear function of the Napierian logarithm not long after the first publication. The two articles complement each other. Charles Matthews (talk) 07:51, 19 February 2010 (UTC) Thanks. My concern was with the 10^7 stuff, which seems arcane even for historical mathematics, and I didn't see a reference for that right away. I'm glad the article was not actually a joke. — Carl (CBM · talk) 11:47, 19 February 2010 (UTC) FWIW, the base 10 log is sometimes called Briggsian logarithm for contrast. Pcap ping 08:40, 19 February 2010 (UTC) If you have a look at Prosthaphaeresis you'll wonder why someone didn't try inventing Napierian logs earlier. Or for something even wierder wikt:logarithmancy which used Napierian logarithms for divination though no-one now know knows how. Dmcq (talk) 13:33, 19 February 2010 (UTC) My thinking is this should really be part of an article called Mirifici Logarithmorum Canonis Constructio.--RDBury (talk) 18:22, 19 February 2010 (UTC) I'm not totally sure that's what I would type into a search box to try and find it! Dmcq (talk) 20:21, 19 February 2010 (UTC) That's why we have redirects. But if the subject is really about logs as they appeared in their original work then the article should be about the original work, especially since we don't already have an article and the subject is certainly notable.--RDBury (talk) 18:10, 20 February 2010 (UTC) I would leave it here. The modern development, sometimes called Napierian, has a perfectly good home under natural logarithm, leaving this title free. On the other hand, an article on the book should be focused on the book itself and the secondary scholarship directly on it. No, it's not a joke - somewhere there should be an explanation that Napier multiplied through by 10^7 because the modern system of decimal places was not yet established. Septentrionalis PMAnderson 20:06, 21 February 2010 (UTC) ## Mathematosis... again In its present form, it is very difficult to see how Wikipedia:WikiProject Countering systemic bias/Mathematosis is constructive. It is substantially a recreation of the deleted essay Wikipedia:Mathematosis. Sławomir Biały (talk) 12:28, 20 February 2010 (UTC) Could, indeed should be copyedited to bring it into line with Quine's view of "systemic bias" effects. It ought to be the case that increased coverage of philosophical logic does not diminish what is written here in mathematics and mathematical logic. Charles Matthews (talk) 12:48, 20 February 2010 (UTC) It looks like he might have started with something which would have been fairly reasonable about countering too much of a mathematical bias in logic and philosophy articles but has recently been renamed and gone to all out attack on mathematicians. If the page was renamed back to something more appropriate and the contents reverted to more reflect the original concerns it could serve some useful function I guess. At the moment it is becoming more nasty silliness like all the other stuff on this that had to be removed earlier. Dmcq (talk) 13:16, 20 February 2010 (UTC) It's an essay, not a page in userspace. I signed up with the systemic bias WikiProject ages ago, and I'm going to treat this as {{sofixit}}. Given the question posed (does mathematical logic as addressed by mathematicians imply a systemic bias in the treatment of logic, a subject that existed for two millennia before the 1930s?), there is a reasonable discussion in there trying to get out. Charles Matthews (talk) 13:54, 20 February 2010 (UTC) I would rewrite the lead to remove the strange emphasis on "mathematosis". At least as the term is described there, it refers to a (real or imagined) chauvinism of certain editors of mathematics, rather than a systemic bias issue. I would also change the title of the article back to the more obvious choice Wikipedia:WikiProject Countering systemic bias/Mathematics. Other than that, the essay is already looking much improved. Thanks! Sławomir Biały (talk) 15:01, 20 February 2010 (UTC) If this is improved then how bad was it before? Maybe I'm showing my bias but it seems like most of the issues brought up in the essay are just silly. Is it our fault that WP Math gets more traffic than WP Philosophy? Are we supposed to merge Field (mathematics) with Field (agriculture)? It seems to me that the previous deletion discussion applies just as well to this version.--RDBury (talk) 18:37, 20 February 2010 (UTC) I agree that the page is still horrible and doesn't belong in project space in this form. It contains some reasonable ideas: E.g. a lot of people would be interested in the philosophical side of certain concepts, but we only present the mathematical side. I guess this is due in part to the relative weight of mathematicians in this project, and in part to a pro-mathematical bias not just among mathematicians but also among those philosophers who deal with logic. Let's not forget that many great early logicians who we now see as mathematical logicians started as philosophers. But there is still too much Gregbard idiosyncracy and nonsense on this page, in particular the underlying assumption that just because mathematicians use a word that has also been used by a philosopher who Gregbard has been reading recently, that philosopher's definition of the word must have more than a marginal connection to the mathematical term of the same name. And of course the silly reference to "mathematosis". Of course, if we assume that mathematicians talking about "classes" in set theory really mean some philosophical concept, whose philosophically relevant aspects they choose to ignore, preferring instead to make some silly superficial games that entirely miss the point, then the accusation of "mathematosis" makes some sense. (Other example: [23].) But in my opinion it is this kind of assumption that misses the point. The fact that Gregbard's arguments only make sense as arguments from ignorance probably explains why he is not getting much support from philosophers in his quixotic struggle. Hans Adler 19:49, 20 February 2010 (UTC) As I say, the page should be fixed up: it's a good exercise in writing for the opponent. Charles Matthews (talk) 08:01, 21 February 2010 (UTC) I don't see how this makes sense. I doubt there are many here who see interdisciplinarity as an opponent. And writing from the POV of a conspiracy theory is also not an example of writing for the opponent. Hans Adler 20:07, 21 February 2010 (UTC) ## Mischief A newly created account User:Basemaze has been engaged in vandalizing displayed math equations with mischievous edit summaries ("fixed an error", etc). Arcfrk (talk) 18:54, 20 February 2010 (UTC) Reverted and warned. (It's not just math articles.) The appropriate venue is probably WP:AIV, rather than here. If he continues, report it there. — Arthur Rubin (talk) 19:24, 20 February 2010 (UTC) I warned, because the edits were in a half hour period over 4 hours ago. If the edits were still occurring, I would have blocked. — Arthur Rubin (talk) 19:53, 20 February 2010 (UTC) It appears that I should have just blocked. He's now reported he has no interest in improving Wikipedia. Oh, well, we still don't block on request. — Arthur Rubin (talk) 08:33, 21 February 2010 (UTC) ## AfD of possible interest It has been suggested to inform this WikiProject of Wikipedia:Articles for deletion/Texvc. I am the nominator for that AfD, by the way. Pcap ping 16:10, 21 February 2010 (UTC) ## Thread of possible interest See WP:ANI#User:Likebox deceptively sourced infraparticle. It's about some physics articles but raises issues for math as well and some of the concerned parties have also edited math articles. As near as I can tell the short story is: someone tagged [citation needed] on some physics articles, Likebox (talk · contribs) and Count Iblis (talk · contribs) felt that the tag was unwarranted as the facts in question were simple calculations, and in response these two users went on a spree of replacing fact tags by deliberately fake references and boasted about it on Jimbo's talk page. But there's a lot of chatter in the thread so it's hard to tell for sure whether that's an accurate description of both sides of the story, it's not clear whether "deliberately fake" means that it doesn't source the calculation at all or merely that it is off-topic for the primary subject of the article in question, and I have not formulated an opinion over whether the citation needed tags really were appropriate. Anyway, the reason I'm bringing this to the project's attention is that a lot of our articles contain things that really are simple calculations that should not need a source according to WP:OR#Routine calculations and WP:Scientific citation guidelines#Examples, derivations and restatements. It would be a shame if someone's misbehavior led to an overreaction in the other direction. —David Eppstein (talk) 02:25, 22 February 2010 (UTC) It seems that the issue at the infraparticle article was a mathematically-inclined explanation for which some editors wanted citations for individual steps. Likebox added some citations for steps, but complained that these didn't really address the point of the article, just the individual steps. Unfortunately, I haven't seen anyone actually analyze whether Likebox's edits were accurate, and so it is hard to tell what's really going on. However, there are two deeper issues with the infraparticle article that make me think it isn't reflective of the problems we encounter with math articles. 1. Apparently the topic is not discussed in textbooks, only in journal articles. Most mathematics topics here are discussed in textbooks or in a significant number of journal articles. 2. Mathematics texts and journals are very likely to have complete proofs for facts they claim, or give references to complete proofs. This makes it easy for us to give citations for proofs and for explanations. Research articles in other fields do not always include proofs for derivations, or only include sketches. This can make it more difficult for them to clearly source things in wikipedia articles, since the literature is not particularly helpful. — Carl (CBM · talk) 02:43, 22 February 2010 (UTC) ### Methods of contour integration As a side note: the discussion about infraparticles somehow led to Methods of contour integration being tagged as POV. Probably more people should watch that article for a little while. — Carl (CBM · talk) 02:50, 22 February 2010 (UTC) Looks like Headbomb needs a little defusing. Pcap ping 12:41, 22 February 2010 (UTC) ## Source code discussion Continuing from the earlier, archived discussion, the thread Wikipedia talk:Manual of Style (mathematics)#Source code and pseudocode has been discussed, and a consensus needs to be reached. LokiClock (talk) 00:02, 23 February 2010 (UTC) ## Paravector Not to disparage the original author, but I've just come across this article which in my most humble opinion, is a little suspicious. I am nowhere near competent enough in pure mathematics to be able to tell whether or not it's a load of hooey or otherwise lacking in rigor, but something stands out about it. One thing that drew my attention but which I'm trying not to be prejudiced by is the personal promotion in the introduction. At the very least, it's quite hard to follow. Could this be checked out by an expert? Sojourner001 (talk) 18:24, 23 February 2010 (UTC) I'm not claiming to be an expert, but the subject does seem to be notable.--RDBury (talk) 19:40, 23 February 2010 (UTC) Clifford algebras are notable; but this seems to be somebody's private nomenclature. Septentrionalis PMAnderson 19:51, 23 February 2010 (UTC) I wasn't questioning its notability, more its truthfulness. Citing sources and demonstrating its utility in deriving a proof surely makes it notable if the proof is correct and the sources verified. Sojourner001 (talk) 21:29, 23 February 2010 (UTC) Geometric algebra always seems to me like a little bit a walled garden. But it is fervently defended by its adherents—who are able to produce sources that are apparently considered reliable within that community. Sławomir Biały (talk) 20:23, 23 February 2010 (UTC) FWIW, the references cited at paravector are all Physics, not Math books. Pcap ping 21:22, 23 February 2010 (UTC) ## Movable cellular automaton followup The Movable cellular automaton article I brought up previously was PRODed. The article has issues as I mentioned above but I didn't think they were clear cut enough for the article to be deleted without a discussion, so I changed the Prod to an AfD. The deletion discussion is at Wikipedia:Articles for deletion/Movable cellular automaton.--RDBury (talk) 05:17, 24 February 2010 (UTC) ## A logical prison Bocardo Prison suffers from poor notation, caused by a traditional example being put together with an existing Venn diagram. Help would be appreciated. Charles Matthews (talk) 12:50, 20 February 2010 (UTC) It looks like as it stands there is more in the article about the syllogism than the prison. Having Venn diagrams for the classical syllogisms seems appropriate but they would go in the Syllogism article rather than this one.--RDBury (talk) 18:52, 20 February 2010 (UTC) Carp on - I created the article yesterday. And asked for help here. Why are you such a bloody negative misery to have around? There is plenty more history that could be added. And it is in fact perfectly reasonable to exemplify the syllogism, considering that it was proverbial for difficulty. Charles Matthews (talk) 07:56, 21 February 2010 (UTC) I think you misunderstood me. All I'm saying is if you want to add material about the syllogism then add it to syllogism article, or create a new article on Bocardo (syllogism). It's good to tell people what Bocardo is and have a link to it, but detailed examples and Venn diagrams belong somewhere where people who are interested will be more likely to find it. As for being a negative misery, you're right, sometimes I am one; so sue me. But I don't make comments here to be liked. I made what I think is a legitimate criticism of the article, with which you can either agree or disagree. And your right in that if I couldn't find anything negative to say then I probably wouldn't say anything. But the point of this forum is to improve math articles, not praise each other's work.--RDBury (talk) 18:46, 21 February 2010 (UTC) Well, water off a duck's back to me, but if you want to review articles, try FA candidates, not stubs that have been on the site for only a few hours that are brought here for help. If I were a newbie, would you have been so negative? Apparently so. And your evaluation of the project's aims seems to leave out human factors, which is a blunder. As well as the irony of being told that the logic has to be segregated in logic articles, with no scope for outreach, just below the thread above. Show me something else where a social science topic gets named after a logic topic - you underestimate our readers with your people who are interested, when the idea would be to get people interested in one valid pattern reasoning out of 15, not to require them to browse the other 14. Charles Matthews (talk) 12:34, 22 February 2010 (UTC) I'm not sure how to respond without making this argument worse than it already is. I didn't say take the logic part out entirely or you can't include anything about logic in a non-logic article, but the beauty of having links is you can point out a connection to another subject and the reader can get more information with a single click. But again, if you disagree then just ignore me. As for rest, this thread seems to have turned into a personal critique of me and my comments, and as much as I would like go on being the subject of the conversation I'm sure everyone else in this forum has had enough by now.--RDBury (talk) 23:00, 22 February 2010 (UTC) Have to agree with RDBury here. The appropriate way to present this unrelated material would be to simply state "the prison was named after a term used in the philosophy of logic..." and link to a further explanation in the relevant article. I can't see how this has become an argument. It's certainly easier to intercept articles as they're created and make sure they prosper, than let them go unnoticed.Sojourner001 (talk) 21:05, 24 February 2010 (UTC) ## C-class? Sorry if this has been discussed earlier, but should WikipRoject Math perhaps introduce a C-class article rating for math articles? Quite a few other projects seem to have introduces a C-class rating. It does seem that there is a fairly substantial difference between start and B classes, so having something in between might not be a bad thing. Nsk92 (talk) 14:02, 23 February 2010 (UTC) Actually it has been raised before but don't feel bad because it probably needed to be raised again. The other issue is we've got this weird B+ rating that no one else uses. The problem is that everyone seems to be split about evenly between about four ways of dealing with the situation, including the camp that thinks everything is fine as is. Really it should be discussed at Wikipedia talk:WikiProject Mathematics/Wikipedia 1.0 since the WP 1.0 page is where the ratings are defined.--RDBury (talk) 17:59, 23 February 2010 (UTC) I remember a while ago there was a vote on Wikipedia:Version_1.0_Editorial_Team or some related project page on whether to introduce a new class and if so, where and what to call it. The consensus was to introduce the "C" class, as you can see by the chart. Though if i recall correctly it was up to the individual projects to adopt this class. In any case, while I see how the B+ class can be helpful, the "C" class fills a much larger gap. (and is actually recognized by the 1.0 project, whereas B+ is not)Kevin Baastalk 18:09, 23 February 2010 (UTC) I too think that it is better for us to be in line with most other wikiprojects, which by and large seem to have adapted a C rating. I also think that the gap between start and B classes is pretty big (considerably bigger than between B and B+) and I personally think that class B rating should be assigned rather conservatively. Another consideration here is that many people from other wikiprojects already assume (sort of by default) that we have a C class rating. I noticed this recently when one of the math articles I created was tagged as C-class[24] (I have since change the math rating there to "start"). This sort of thing is likely to happen more often as time progresses. Nsk92 (talk) 18:38, 23 February 2010 (UTC) I added a proposal at at Wikipedia talk:WikiProject Mathematics/Wikipedia 1.0 with links to and a summary of previous discussions. I really think it's better to keep the discussion on a single page because it's a lot of work to track down various threads from 50+ archive pages. There is no sense in rehashing old arguments just because they're buried somewhere.--RDBury (talk) 19:10, 23 February 2010 (UTC) Wikipedia 1.0 is a foolish idea. The one thing Wikipedia has never been able to do is rate articles consistently and on zubstantive merit; it's very hard to do it, and a bunch of ad hoc committees will not be cosistent - even if they had fewer cranks than any WikiProcess accumulates. Any change of practice done to assist it should be opposed. Septentrionalis PMAnderson 06:00, 24 February 2010 (UTC) To me Wikipedia 1.0 is just a label. The maths rating tags are a means by which people in this project can keep track of the progress of work on math articles and are for our own benefit. If some other project wants to use them too I'm not going to stop them.--RDBury (talk) 16:44, 24 February 2010 (UTC) Then do we, looking only at our own progress, need a C tag? That's a sensible question, but I'm not sure of the answer. Septentrionalis PMAnderson 21:21, 24 February 2010 (UTC) ## AfD of interest Wikipedia:Articles for deletion/List of numerical analysis software. Pcap ping 22:30, 24 February 2010 (UTC) ## Featured picture candidates There are currently two math related pictures being discussed for featured pictures: File:Pythagoras-2a.gif and File:Penrose Tiling (Rhombi).svg. See Wikipedia:Featured picture candidates/File:Penrose Tiling (Rhombi).svg and Wikipedia:Featured picture candidates/File:Pythagoras-2a.gif for discussions.--RDBury (talk) 08:22, 26 February 2010 (UTC) ## More possible hoaxes Zbacnik conjecture was prodded as a hoax by someone else and I just prodded the related article Luce number. There seems to be a bump in the number of questionable new articles recently so perhaps some extra eyes on Wikipedia:WikiProject Mathematics/Current activity would be helpful.--RDBury (talk) 06:37, 27 February 2010 (UTC) # Mar 2010 ## Unsourced mathematical biographies There has been a lot of pressure lately to summarily delete all inadequately-sourced biographical articles, and some of these articles are ones this project may wish to preserve. Please see Wikipedia:Pages needing attention/Mathematics, especially the sections on unsourced articles and unreliably sourced articles and add appropriate sources to the biographical articles (and others, but the biographical ones are urgent). —David Eppstein (talk) 19:21, 21 January 2010 (UTC) Here is a list of all the math articles I could find that are in Category:All unreferenced BLPs. Note that many of them will actually be referenced (external links count for this purpose). To coordinate work, simply remove names from the list below when you are done with them. I can always generate a new list later to see if any were missed. — Carl (CBM · talk) 19:44, 21 January 2010 (UTC) I'm a bit lost with all these recent discussions; are people going to delete unreferenced BLP without warning, or is there going to be a WP:PROD-like process? — Miym (talk) 19:46, 21 January 2010 (UTC) For the moment, the safest assumption is that they might be deleted without warning; who know how things will turn out. In any case, checking the articles and correcting the templates is certainly a good idea. If someone does delete an article, and you would like it to be undeleted to fix it, just contact an admin (David Eppstein and I are both admins). — Carl (CBM · talk) 19:53, 21 January 2010 (UTC) Thanks for the list Carl. I'm also an admin, other members of this project who are admins include: Charles Matthews and Oleg Alexandrov. Paul August 20:39, 21 January 2010 (UTC) I would similarly be happy to undelete an article on request. CRGreathouse (t | c) 20:41, 21 January 2010 (UTC) I'm also an admin, for the moment, and would happen to undelete an article on request. (After checking for vandalism, of course.) — Arthur Rubin (talk) 20:54, 21 January 2010 (UTC) At least some of these could be fixed by turning the external links section into a references section.--RDBury (talk) 21:10, 21 January 2010 (UTC) Not to belittle or deemphasize the importance of history... but to be quite frank I dont think the history of mathematics or the biographies of mathematicians are of any consequence. These articles - though important in their own right - should be maintained by the historians and not the mathematicians. History is a distraction to those with an interest in math, and only adds superfluous content to already lengthy articles. I recommend starting a Mathematics History project, separate and distinct from the Mathematics project, to be a sub-categorization of both the Mathematics Project and the History project, operated and maintained in conjunction by each. --98.247.99.158 (talk) 23:35, 14 February 2010 (UTC) On the contrary, the history of mathematics and the biographies of mathematicians are of considerable consequence, both in their own right, and in relation to mathematics. And while the contributions of historians would be very helpful and welcome in this area, so are the contributions of mathematicians. As far as "history [being] a distraction to those with an interest in math" — not for me and many others I know. And not only is the historical content in mathematics articles not "superfluous", it is in fact a requirement for a complete treatment of a subject. Paul August 18:46, 15 February 2010 (UTC) By the way, there is a recently opened RfC, in progress, on the unreferenced BLP controversy, Wikipedia:Requests for comment/Biographies of living people. Those with an interest in the issue might want to comment there. Nsk92 (talk) 01:36, 22 January 2010 (UTC) ### List This was obtained by category intersection. Pcap ping 04:34, 23 January 2010 (UTC) I merged and pared down both lists to include only the remaining articles that have neither been sourced nor deleted. —David Eppstein (talk) 03:51, 6 February 2010 (UTC) I added a few more. — Carl (CBM · talk) 12:09, 10 February 2010 (UTC) ### Whack-a-mole? Apparently there are several IP editors that just add back the {{unreferencedBLP}} tag. I've noticed this on several articles. An example relevant here is [25]. Pcap ping 05:02, 23 January 2010 (UTC) To be fair, Sourav Chatterjee was pretty clearly a vanity piece. I have hacked at it some. — Carl (CBM · talk) 05:27, 23 January 2010 (UTC) AfD then? Is the award significant? Pcap ping 05:31, 23 January 2010 (UTC) I am not at all familiar with the person. There is the award in combination with the editorship, which is uncommon for someone 3 years out of grad school in pure math; I don't know about statistics. I think it would be a close call on AFD. — Carl (CBM · talk) 05:39, 23 January 2010 (UTC) Apparently, some of the puffery was added by someone from India fairly recently. Pcap ping 05:42, 23 January 2010 (UTC) Yeah; the article says Chatterjee is at Courant, so who knows. It could be him, a family member, a long-lost lover, or a random admirer. — Carl (CBM · talk) 05:44, 23 January 2010 (UTC) By the way, some Kansas IP tried to stub the article a couple of times, and the anti-vandal squad reverted. Obviously all this happened just because it lacked references :P Pcap ping 05:51, 23 January 2010 (UTC) For those not watching the article: Wikipedia:Articles for deletion/Sourav Chatterjee. Pcap ping 06:14, 23 January 2010 (UTC) I know him personally and some of his work. I'm pretty sure he didn't write this article. He might be exceptionally good, but it certainly seems too early to have an article on him. For instance, I know a lot of youngish probabilists who are more notable than him (say, based on citations of their first ten papers on Google Scholar, or on prizes) without wikipedia articles on them. But, with the current more realistic article, I don't think it matters much if it is deleted or not. --GaborPete (talk) 05:22, 27 January 2010 (UTC) I agree with Gabor. Boris Tsirelson (talk) 11:42, 27 January 2010 (UTC) FYI: I asked Jimbo about his opinion about the article, after the AfD had closed. He thinks that having articles like that around is "probably a lot more trouble on average than they are worth". Pcap ping 10:17, 10 February 2010 (UTC) Note: I restored the above thread. Do we still need this? Paul August 20:09, 28 February 2010 (UTC) I don't know whether we still need this. Discussion and confusion seems to be ongoing at Wikipedia:Requests for comment/Biographies of living people but may eventually lead to a process whereby unreferenced BLPs are deleted after some waiting period. I think the clear-cut cases from the math list have mostly already been dealt with, but we can save some trouble now by finishing off the list; if it's just the ones listed above it doesn't seem like too much to handle. —David Eppstein (talk) 20:21, 28 February 2010 (UTC) ## Regressive discrete Fourier series Regressive discrete Fourier series was until moments ago a complete orphan; now it's linked to from the list of Fourier analysis topics. I added Category:Fourier analysis, so the bots should add it to the list of mathematics articles and then to our current activities page. In the mean time, do what you can with it. Michael Hardy (talk) 19:30, 27 February 2010 (UTC) ## Resources box I added a few items. Enjoy, but if not, undo.--RDBury (talk) 19:44, 28 February 2010 (UTC) I surmise that you're referring to this: Wikipedia:WikiProject Mathematics/Nav. Michael Hardy (talk) 20:20, 28 February 2010 (UTC) ## Gravitational potential A third set of eyes would be appreciated at Gravitational potential. I draw the line at personal attacks like this. Sławomir Biały (talk) 02:22, 28 February 2010 (UTC) Please help. The editor is now insistent on edit warring to include extremely dubious content in the article, and remove my best effort at a compromise. Sławomir Biały (talk) 01:33, 2 March 2010 (UTC) I second this plea. I've tried to help a bit, but clearly something more is required. RobHar (talk) 02:55, 2 March 2010 (UTC) ## Elliptic curve primality testing I've done enough cleanup on elliptic curve primality testing for one night. Various conventions of WP:MOS and WP:MOSMATH still need to get applied here. But also: the article is an orphan: lots of other articles should link to it and do not. Michael Hardy (talk) 04:16, 1 March 2010 (UTC) From a cursory look, it's a canonical example of textbook exposition. For example, the end of the lead that spills into the first section ("We will now state a proposition …") made me cringe. Has anyone checked whether this text has been lifted wholesale from a book? Arcfrk (talk) 17:30, 1 March 2010 (UTC) That may simply be bad style, but the paper credited was Goldwasser, Shafi, Kilian, Joe, "Almost All Primes Can Be Quickly Certified". I haven't followed the link, but if it really dates primality testing from Gauss, it is unusually inept even for mathematicians' history of mathematics. I suspect that, at least, is home-grown folly. Septentrionalis PMAnderson 23:30, 1 March 2010 (UTC) It doesn't. "Fermat, Euler, Legendre, and Gauss", after a mention of Eratosthenes. Our editor is unable to convey the sense of his source, so I doubt he is plagiarizing. Septentrionalis PMAnderson 23:32, 1 March 2010 (UTC) ## Reciprocal property Is the article titled reciprocal property worth anything? Michael Hardy (talk) 04:32, 1 March 2010 (UTC) The reference given is totally inappropriate but I searched Google books and saw it being used in several places as a phrase with more than the obvious meaning. In particular the Penny Cyclopedia has "A reciprocal property is one which each of two things has with reference to the other; thus if A and B be what are called conjugate diameters of a conic section, the tangent at either extremity of A is parallel to B, and that at either extremity of B is parallel to A. Hence these lines are reciprocally connected with each other, and are therefore called conjugate; for the word conjugate, which denotes joined, generally means joined by a reciprocal property." Not sure that the article can be extended beyond a DICDEF or whether the terms has any modern currency. It seems to not be a strictly math term so maybe this isn't the place to ask.--RDBury (talk) 05:54, 1 March 2010 (UTC) Is it attested in the past century? Obscure and archaic terminology probably belongs on Wiktionary, with a redirect to the modern term, which should link to Wiktionary. In this case, that would be reflexive relation. Septentrionalis PMAnderson 16:30, 1 March 2010 (UTC) It's not the same as a reflexive relation, the example given in PC shows that. The problem is the term seems to be used in a number of unrelated subject; I saw something about viscous fluid flow, the RSA algorithm, the properties of antennas, and others, all using it in a different way but rarely actually defining it or at least not where you can see in the book preview. If you want to do the research to turn this into an workable article then I'm not going to say it's impossible. On the other hand I didn't see any evidence that the article as created isn't just an extrapolation of a phrase used on a speculative science calendar store website. This is why Wikipedia has a rule about adding material that's not properly referenced, it takes longer to fix it than it does to add it, even if you end up deleting it.--RDBury (talk) 18:38, 1 March 2010 (UTC) My apologies, you are of course correct; this is an 1-to-1 Symmetric relation: A is related to B iff B is related to A. Septentrionalis PMAnderson 23:20, 1 March 2010 (UTC) ## Perfect Cube Confusion Hello, I am wondering whether 0 is a perfect cube or not? Math Champion | sign! 04:07, 2 March 2010 (UTC) Yes, it is; it's the cube of the integer 0. In the future, please ask this sort of question at Wikipedia:Reference desk/Mathematics. --Trovatore (talk) 04:25, 2 March 2010 (UTC) ## Covariance (categories) What do we think of the article titled Covariance (categories)? Michael Hardy (talk) 19:49, 26 February 2010 (UTC) Being somewhat of a dilettante when it comes to category theory, it is difficult for me to get any meaning out of the article. Also I get no hits whatsoever for the phrase "quantitative category theory" in either Google, Google books, or Google scholar. Sławomir Biały (talk) 20:59, 26 February 2010 (UTC) It appears to be integrating over a "real or complex" category; I may also be a dilettante, but I've never heard of either, and the idea of integrating over a large category makes my head hurt. Septentrionalis PMAnderson 00:06, 27 February 2010 (UTC) The claim that "Cov(FG) is negative iff exactly one of F and G is contravariant" is especially mysterious to me, since, if the preceding definition makes any sense at all, it (a) requires F and G to be covariant and (b) defines Cov to be always positive. Algebraist 00:15, 27 February 2010 (UTC) I'd like to put money down on this article being completely made up. RobHar (talk) 00:28, 27 February 2010 (UTC) The user seems to be a subtle vandal. [26], [27], and he was also responsible for the now-deleted mitimorphism (which, IIRC, provoked a discussion much like the present one.) Ozob (talk) 04:10, 27 February 2010 (UTC) Just prod it as gibberish and put a warning on the user's talk page. In fact I think I'll just go ahead and do that now. It doesn't even make sense as having substituted different words for something else. Dmcq (talk) 09:43, 27 February 2010 (UTC) And if you want proof it is rubbish how about integrating the absolute value of something and getting a negative number? Dmcq (talk) 10:05, 27 February 2010 (UTC) Nonsense, but rather well-written and clever nonsense, not like most attempts. Michael Hardy (talk) 16:27, 27 February 2010 (UTC) Not sure how to mark this in the prod template, but IMHO it would be better to redirect the article to Functor#Covariance and contravariance than to delete it.—Emil J. 15:37, 1 March 2010 (UTC) I suppose you could just change the page to a redirect rather than wait for the prod to expire. Dmcq (talk) 16:21, 1 March 2010 (UTC) OK, since nobody objected I've done just that.—Emil J. 11:12, 2 March 2010 (UTC) ## A trigonometric identity for a circulant matrix A trigonometric identity for a circulant matrix seems to be the work of a competent mathematician unaware of Wikipedia's policy against original research and the one against identifying the author by name within the article. It's on AfD. Michael Hardy (talk) 04:27, 2 March 2010 (UTC) Userified: User:Daviddaved/A trigonometric identity for a circulant matrix. CRGreathouse (t | c) 06:12, 2 March 2010 (UTC) I just had a look at that and I must admit I'm a bit surprised if nobody has done something like that before. It looks an interesting formula but if it isn't in a reliable source that's that I guess. Dmcq (talk) 15:33, 2 March 2010 (UTC) If you set x = y2 and factor, it ought to resolve into a fairly predictable statement about symmetric polynomials of the roots of unity; which may be why no reliable source has bothered. Septentrionalis PMAnderson 20:06, 2 March 2010 (UTC) It doesn't resolve into anything straightforward to me. It does involve symmetric polynomials of the real part of the roots of unity which should resolve into something reasonable and here is shown to do so but I haven't seen it worked out before. Dmcq (talk) 23:46, 2 March 2010 (UTC) ## Hyperbolic geometry The section Homogeneous structure was recently added to the hyperbolic geometry article. Apart from not including sources, and not being particularly clear, the question I wanted to ask is: in what sense is a geometric space "isomorphic" to some group? Does this mean the symmetry group of the space is isomorphic to the group ? There are other wikipedia aricles that also say such and such a space is isomorphic to such and such a group without first defining a group on the space. Charvest (talk) 14:53, 2 March 2010 (UTC) It says the space is isomorphic to the quotient of two groups, I don't think it should be taken to mean the quotient group of two groups. Given any homogeneous space, it's symmetry group G will be transitive, so the space can be identified with G/G1 where G1 is the subgroup of G that fixes a point. Here the quotient just means the collection of cosets and is not itself a group in general. That being said, the section seems to assume a familiarity with Minkowski space that I, for one, don't have.--RDBury (talk) 16:36, 2 March 2010 (UTC) Not a quotient group! Thanks. I'll continue this at the reference desk. Charvest (talk) 22:46, 2 March 2010 (UTC) ## A general question regarding sources and citation I was wondering what I can do in the following situation: I am reading an article and there is a statement I cannot prove myself nor do I know any source as where to find a proof for the statement. What is the best way to request a source or reference for the statement? Is it ok to do so even? I think that every statement made in an article should be either clear to the reader with a certain mathematical eduaction or should be referenced. Quiet photon (talk) 15:08, 2 March 2010 (UTC) You can add the template {{fact}} to the article just after the claim, and leave a brief query on the talk page. If that doesn't give a response in a reasonable amount of time, try asking here for people to look at it. But in general it's best to start by just asking on the talk page of the article; the people who have the article on their watchlist may be in a better position to give you an answer. — Carl (CBM · talk) 15:19, 2 March 2010 (UTC) (e/c) First, look down to the "References" section. Chances are that it gives a book covering the topic or a similar general source which includes the statement, it's just that the article is missing detailed inline refs. Failing that, you can request a citation by adding a {{cn}} template after the statement. However, bear in mind that if it is not a high-traffic article, it may easily take months until someone adds a source (or deletes the claim). If you really need a proof now, you may be better off by asking at the Math Reference Desk.—Emil J. 15:27, 2 March 2010 (UTC) Thank you for your answers! So just to check if I understand correctly, it is neither the goal of the Mathematics Portal to reference every statement made in an article nor to provide the proofs themselves? Or is it just that at the moment other things, such as writing missing articles or improving the overall quality are more important? Please forgive my tenacity, I really want to contribute, but I feel that I have to understand the goals and conceptions of the Mathematics Portal first. Quiet photon (talk) 15:44, 2 March 2010 (UTC) In theory, all statements on WP are supposed to be referenced, but many articles are far from this goal. On the other hand, we are not supposed to provide proofs (unless the particular proof has itself encyclopedic merit).—Emil J. 15:49, 2 March 2010 (UTC) The goal is to provide enough referencing to (1) provide resources for the reader to look into the material in greater depth and (2) give specific inline references for things that need them. Those things are usually obvious: direct quotes, statements of opinion, and controversial or surprising statements should ideally have inline references. For general articles that could be rewritten from a single textbook, we don't usually try to put inline citations on every fact, but we do try to reference a couple good textbooks where someone could learn about the facts in the article and more. It is not our goal to include proofs of every fact. This is in line with the idea that Wikipedia is an encyclopedia, not a textbook. If one compares other sources like the CRC Concise Encyclopedia of Mathematics or the Stanford Encyclopedia of Philosophy, they also do not try to prove every fact they mention. The best advice for getting started is: pick an area you know about, pick an article that needs work, and expand it. Keep what you add in line with what can be found in the literature about the area, and add references to anything that a careful referee would ask you to reference in a research paper. — Carl (CBM · talk) 16:52, 2 March 2010 (UTC) Very helpful, thank you. I have seen only one proof so far in the Wikipedia, and I did some searching and I found it again: Conservative force under mathematical description. At the time I was learning about that I was very greatful for it. I think it is a great way implement proofs if needed and I, if I ever get to edit or write an article will use it when I see need for a proof, if that's ok? Quiet photon (talk) 17:36, 2 March 2010 (UTC) (e/c)The goal of references is to establish verifiability, resources for readers to get more information should come under the heading of Further Reading or External Links. Verifiability through reliable external sources is one of the pillars of Wikipedia and any material that may be questioned should have a citation.--RDBury (talk) 17:42, 2 March 2010 (UTC) References are both for verifiability and to help the reader explore the topic; these are complementary goals, not conflicting ones. Many of our articles use "general references", because much of their material is unlikely to be "questioned", and if it is we can easily point it out in the literature. It's important to remember that "verifiable" means "in principle, this material can be found in the literature". It is perfectly possible for material to be verifiable even though an inline citation is not provided. This is why I said, "keep what you add in line with what can be found in the literature about the area". — Carl (CBM · talk) 19:10, 2 March 2010 (UTC) .+1--Kmhkmh (talk) 22:44, 2 March 2010 (UTC) One might also try: (1) asking the person who put the statement there in the first place; and (2) asking at Wikipedia's mathematics reference desk. Michael Hardy (talk) 21:40, 2 March 2010 (UTC) I would mention as no-one else seems to the Scientific citation guidelines, the gist of which is that science is not BLP. While a biography (or history, or geography) article consists of facts all of which should be individually verifiable it's often unnecessary for science, where a lot of the theory on a page is common, uncontroversial knowledge. Better to provide a two or three good general references which cover the whole subject well. This does not stop editors questioning dubious statements or providing references for them, but maybe explains why good maths articles in particular have few citations per paragraph than e.g. good biographies.--JohnBlackburnewordsdeeds 22:27, 2 March 2010 (UTC) It seems to me that what you're saying is consistent with the Scientific citation guidelines. It already says the scientific subjects don't need a footnote for each statement, especially when that would disrupt the flow of the article, so I'm not sure what in the guidelines you're saying don't need to follow. I object to long articles covering a variety of subtopics where there is not way of telling which section comes from which source, if any. Newton's method is like this, there are lots of references but some of them are general numerical analysis texts and there is no way of knowing without going through all the references which are intended to support which facts. This is a bit of a shame because the article itself is well written enough to qualify for GA status (imo), but with the referencing style as it I doubt it would get past even a preliminary review.--RDBury (talk) 05:10, 3 March 2010 (UTC) @Quiet photon: If you want to provide access to proofs to the readers of a math article, you can do so by providing references to literature/journal articles containing them (also online copies of them). In addition you could provide link to some website or a wikibook containing the proof in the external links section.--Kmhkmh (talk) 22:41, 2 March 2010 (UTC) ## AN/I thread A thread related to the article Zeno's paradoxes has been opened at Wikipedia:Administrators' noticeboard/Incidents#User:Steaphen. Nsk92 (talk) 23:51, 2 March 2010 (UTC) I moved to WP:AN where topic bans are usually discussed. Pcap ping 01:57, 3 March 2010 (UTC) ## Featured picture candidates part 2 Of the two recent nominations for featured picture, File:Pythagoras-2a.gif was promoted and is now a featured picture. File:Penrose Tiling (Rhombi).svg did was not promoted even though there were no oppose votes. Thanks to User:Noodle snacks for making the nominations. There is a new nomination File:Desargues theorem.svg with discussion at Wikipedia:Featured picture candidates/File:Desargues theorem.svg. These featured picture discussions don't appear in either Wikipedia:WikiProject Mathematics/Current activity or in Wikipedia:WikiProject Mathematics/Article alerts, nor do the featured pictures appear in Wikipedia:WikiProject Mathematics/Recognized content. One issue seems to be that the 'maths rating' template does not include a file class so pictures related to WPM use the outdated 'maths banner' template instead.--RDBury (talk) 02:42, 5 March 2010 (UTC) ## Spaced en-dashes Remember a few months ago when someone tried to rename Seifert–van Kampen theorem to "Seifert – van Kampen theorem" because the Manual of Style said that was the right thing to do, despite the fact that no math publications spell it that way? There's now an RFC going on about this issue (and about en-dashes used to separate multiple items in similar contexts): please see Wikipedia talk:Manual of Style#RfC: Disjunctive en dashes should be unspaced, and leave your opinion there if you have one. —David Eppstein (talk) 04:30, 6 March 2010 (UTC) ## Coxeter-Dynkin diagrams: PNG or SVG < removing my own entry here; belongs in Talk:Coxeter–Dynkin diagram > —Tamfang (talk) 20:01, 7 March 2010 (UTC) ## Pros and cons of notations for sine and cosine series Opinions of mathematicians (and others) are welcomed at Talk:Trigonometric_functions#Pros_and_cons_of_notations_for_series. Michael Hardy (talk) 05:31, 8 March 2010 (UTC) ## Proposed move of Satisfiability and validity FYI [[28]] 65.46.253.42 (talk) 21:28, 8 March 2010 (UTC) ## Proposed move of Continuous function (topology) Should the page be moved to Continuous map? Comment at talkpage. Tkuvho (talk) 12:26, 10 March 2010 (UTC) The discussion thread seems to be here. — Carl (CBM · talk) 12:41, 10 March 2010 (UTC) ## Proposed merger of Real part and Imaginary part I'm considering merging Real part and Imaginary part into a new article Real and imaginary parts; would anyone object to that? ― A._di_M. (formerly Army1987) 15:54, 10 March 2010 (UTC) Be WP:BOLD! Sounds good to me. CRGreathouse (t | c) 03:07, 11 March 2010 (UTC) ## Proposed deletion of "Research Students Conference Probability and Statistics" I don't really have particularly strong feelings one way or the other about this proposed deletion, but the comments in the deletion discussion so far seem like examples of the reasons why I sometimes feel as if people who spend all their time hanging around the AfD pages are not respectable: Wikipedia:Articles_for_deletion/Research_Students_Conference_Probability_and_Statistics#Research_Students_Conference_Probability_and_Statistics. Michael Hardy (talk) 06:41, 11 March 2010 (UTC) ## "Skew shape", "skew diagram"? The article titled Young's lattice refers to the "skew shape" p/q, at the point where it's giving the Möbius function of the lattice. It is unclear what that term means. In Young_tableau#Skew_tableaux we find the term again, but it's not clear how the reader of Young's lattice would find his way there. It says "if the skew shape is a disjoint union of squares", but I wonder what in this context could possibly not be a disjoint union of squares. So can someone clarify, within the article? Michael Hardy (talk) 19:37, 7 March 2010 (UTC) I was just wondering that myself. I also don't know what it means. —David Eppstein (talk) 19:48, 7 March 2010 (UTC) Perhaps they mean that the difference is a "disconnected union" rather than "disjoint union"? JRSpriggs (talk) 20:48, 7 March 2010 (UTC) It may be a case of "too much of a good thing" (by an expert). A clear enough definition appears in the first line, but it is then obscured by too many caveats and qualifiers. I did a bit of detective work. Here is an old revision where skew diagrams are defined the way I first wrote it, and here is Marc's expansion that's closer to the present form. As for the course of action, a picture would help a lot, and I don't think it's worthwhile to accent attention on the ambiguity of the notation ("skew diagram" vs "skew shape") too much. Arcfrk (talk) 05:16, 8 March 2010 (UTC) Oh: You mean in the first line of a section of the article titled Young tableau, not the first line of anything in the other article that is what I was asking about. Michael Hardy (talk) 05:34, 8 March 2010 (UTC) There are two confusions going on. For the terminology, a "skew shape" is a pair of partitions (comparable in Young's lattice), while a "skew diagram" is a set of squares that can be obtained as set theoretic difference of their diagrams. The map from skew shapes to skew diagrams is not injective, which is why one must take care to distinguish, and not say (or define) skew diagram when a skew shape is meant (it is like confusing "fraction" and "rational number" when talking about "the denominator of a rational number"). The Young diagram article is excessively explicit about this, to which I plead guilty; blame frustration about the fact that more than half of the authors (even the best) get this wrong. But in this case the real confusion was using the term "disjoint" where "disconnected" should have been used (a set of squares being considered connected if they are joined via common edges, not just corners). So the proper thing to say that the Möbius function taken at a skew shape is nonzero if and only if all squares of the corresponding skew diagram are disconnected. I've made such a change. Marc van Leeuwen (talk) 14:16, 13 March 2010 (UTC) ## Featured picture candidates part 3 An alternate version of the Desargues theorem diagram File:Desargues theorem alt.svg was promoted to featured picture. However, with all the changes that happened in the process the lines are slightly misaligned at the point c so some repair would be helpful. Meanwhile there is a new nomination, see Wikipedia:Featured picture candidates/File:BIsAPseudovector.svg.--RDBury (talk) 05:18, 12 March 2010 (UTC) ## Proposed merger of Mathematical constant and Constant (mathematics) IRP has proposed a merger of Mathematical constant and Constant (mathematics). Discussion is here. Gandalf61 (talk) 11:04, 14 March 2010 (UTC) ## Help with History of Logic? The article History of logic has been nominated for a featured article here. The nominating editor has asked me for help concerning the post-WWII period, asking if forcing was the only significant result, and if "reverse mathematics" ought to be mentioned (see: User talk:Paul August#Logic after WW2). Any assistant anyone could give would be appreciated. Thanks, Paul August 15:21, 14 March 2010 (UTC) ## Crooked egg curve Could those who know algebraic geometry comment at Wikipedia:Articles for deletion/Crooked egg curve? Michael Hardy (talk) 03:26, 15 March 2010 (UTC) ## article assessments: issues with "field" and progress report I posted a few months ago about plans to work on the article assessments. Here is a progress report on wha's been accomplished, some issues I noticed when I was doing it. — Carl (CBM · talk) 13:17, 12 March 2010 (UTC) ### Status updates Filling in assessments There were about 1,400 articles that had a maths rating tag with incomplete information (at least one of the quality, priority, and field parameters was not filled in). I went through and assessed these. Many of them were stubs, which were easy. Very few of the unassessed ones were long articles where seriously reading the article was necessary. Right now, we have about 7,100 articles with talk page assessments, and about 23,000 on the list of mathematics articles. We seem to gain 2-3 talk page assessments per day, on average. New WP 1.0 bot In January, the new WP 1.0 bot was turned on. It uses the same templates as the old one, but now the information is stored in a database on the toolserver where it can be searched dynamically. Eventually, this system is going to replace the VeblenBot system to make per-project tables for the math project. New log page format The new WP 1.0 bot keeps its log pages in a more useful format. The log is at Wikipedia:Version 1.0 Editorial Team/Mathematics articles by quality log Tools I have several tools for article assessments listed on User:CBM. ### Issue: assigning fields to articles Right now, each article with a maths rating template is assigned to exactly one of these fields: general, basics, analysis, algebra, geometry, applied, probability and statistics, number theory, discrete, foundations, mathematical physics, topology, history, mathematicians There are a few problems I noticed when I was assessing articles: • Algebraic geometry is particularly difficult to fit into this scheme, and I think its articles are split between algebra and geometry. Riemannian geometry, Lie theory, dynamical systems, and category theory are also difficult to fit into the system. • Some articles fit into more than one field. For example, C*-algebra would fit into both mathematical physics and analysis, and Cohomology would fit into both topology and algebra • The geometry category includes both pure geometry and a large number of articles on polyhedra, polytopes, and similar objects. Splitting the polyhedra into their own field would probably make it easier to keep tack of them separately. I think this is one of our less well-known resources: we have an enormous library of articles on different polyhedra. It's certainly worth making it possible to put more than one field on an article. But I think that revisiting the selection of fields would be worthwhile. One nice thing about our current system is that it is not too fine. I think that the MSC rating system is too fine four our needs. But one possibility for us would be to start with the MSC 2010 system (just the 2-digit codes) and then combine those into groups to form our fields. For example, we could make a list of the MSC codes corresponding to "topology", and then say that our "topology" field corresponds to the topics listed under those MSC codes. If a topic would be normally be filed under more than one MSC code, then we can assign it to more than one of our "fields" as appropriate. How do other people feel about that? — Carl (CBM · talk) 13:17, 12 March 2010 (UTC) I think the "applied" category should definitely be replaced with more specific ones such as "optimization", "game theory", "numerical analysis" and "information theory". And there should be one for "dynamical systems" and one for "computation". Bethnim (talk) 16:46, 12 March 2010 (UTC) Separate categories for "algebraic geometry", "differential geometry" and "category theory" would also be reasonable. Bethnim (talk) 16:56, 12 March 2010 (UTC) We have to be careful not to make them too fine, though, or the fields become just a replacement for the categories already on the articles. The idea behind the fields to to give a relatively coarse splitting. The benefit of matching things with MSC fields is to make it easier to tell what articles go in each field. For example, when you say "computation", I don't know if you mean numerical analysis or recursion theory. Similarly, I would not be able to guess what you mean by "optimization". — Carl (CBM · talk) 19:08, 12 March 2010 (UTC) I also think that the fields, whatever they are chosen to be, should remain course-grained. CRGreathouse (t | c) 21:08, 12 March 2010 (UTC) Me too. I like the idea of being able to assign multiple fields to the same article. RobHar (talk) 05:00, 13 March 2010 (UTC) I mentioned this above, but if there changes being made anyway, is there any chance of getting file class added so we don't have to mess around with a separate template for images? There has been a lot of activity for featured pictures lately and while I don't mind posting notification manually it would be nice if it was handled by the normal machinery. There are a few other non-rating classes that other projects use as well such as list.--RDBury (talk) 14:41, 13 March 2010 (UTC) The current template already supports FL-Class and List-Class; VeblenBot just needed to be told to look at them, which I did just now. The WP 1.0 bot tables have had them for a while (here). The bot that does the current activity page needs to be updated to look for FP discussions; maybe a List of mathematics images could be created to facilitate that. The issue with the math rating template and images is that it needs to be set up so that the images are automatically rated as NA-priority. If we are already going to be revamping the field system, this can be done at the same time. — Carl (CBM · talk) 16:00, 13 March 2010 (UTC) I went through the list of top-level MSC fields and tried to fit them into a small number of fields that we could use to classify articles. Here is the resulting list. I've left out 00-XX General, since it doesn't fit anywhere. I've put several MSC fields into several WP fields; sometimes this is because a single MSC field doesn't fit well anywhere (such as K-theory) and other times it's because the MSC fields are too broad (e.g., 01-XX History and biography). Keep in mind that I'm way out of my depth here, as I've never read even a single paper in most of these fields. Some of my choices will be completely wrong, so I invite corrections. Field MSC numbers History • 01-XX History and biography Biography • 01-XX History and biography Foundations • 03-XX Mathematical logic and foundations • 18-XX Category theory; homological algebra Discrete mathematics • 05-XX Combinatorics • 39-XX Difference and functional equations • 52-XX Convex and discrete geometry • 68-XX Computer science Algebra • 06-XX Order, lattices, ordered algebraic structures • 08-XX General algebraic systems • 12-XX Field theory and polynomials • 13-XX Commutative algebra • 14-XX Algebraic geometry • 15-XX Linear and multilinear algebra; matrix theory • 16-XX Associative rings and algebras • 17-XX Nonassociative rings and algebras • 18-XX Category theory; homological algebra • 19-XX K-theory • 20-XX Group theory and generalizations Number theory • 11-XX Number theory Geometry and topology • 14-XX Algebraic geometry • 19-XX K-theory • 51-XX Geometry • 52-XX Convex and discrete geometry • 53-XX Differential geometry • 54-XX General topology • 55-XX Algebraic topology • 57-XX Manifolds and cell complexes • 58-XX Global analysis, analysis on manifolds Analysis • 19-XX K-theory • 22-XX Topological groups, Lie groups • 26-XX Real functions • 28-XX Measure and integration • 30-XX Functions of a complex variable • 31-XX Potential theory • 32-XX Several complex variables and analytic spaces • 33-XX Special functions • 34-XX Ordinary differential equations • 35-XX Partial differential equations • 37-XX Dynamical systems and ergodic theory • 39-XX Difference and functional equations • 40-XX Sequences, series, summability • 42-XX Harmonic analysis on Euclidean spaces • 43-XX Abstract harmonic analysis • 44-XX Integral transforms, operational calculus • 45-XX Integral equations • 46-XX Functional analysis • 47-XX Operator theory • 49-XX Calculus of variations and optimal control; optimization • 58-XX Global analysis, analysis on manifolds Mathematical physics • 37-XX Dynamical systems and ergodic theory • 70-XX Mechanics of particles and systems • 74-XX Mechanics of deformable solids • 76-XX Fluid mechanics • 78-XX Optics, electromagnetic theory • 80-XX Classical thermodynamics, heat transfer • 81-XX Quantum theory • 82-XX Statistical mechanics, structure of matter • 83-XX Relativity and gravitational theory • 85-XX Astronomy and astrophysics • 86-XX Geophysics Applied mathematics • 41-XX Approximations and expansions • 65-XX Numerical analysis • 90-XX Operations research, mathematical programming • 91-XX Game theory, economics, social and behavioral sciences • 92-XX Biology and other natural sciences • 93-XX Systems theory; control • 94-XX Information and communication, circuits Probability and statistics • 37-XX Dynamical systems and ergodic theory • 60-XX Probability theory and stochastic processes • 62-XX Statistics Education • 97-XX Mathematics education Ozob (talk) 17:27, 13 March 2010 (UTC) Judging by our current categories as well as the MSC listings, I'd say we shouldn't split out history. (We only have 68 articles in it, while the others average ~600.) Would Education be roughly the same as our current Basics, along with articles about mathematical pedagogy? If not, I don't think there would be enough to break that out on its own. I'm not sure that 33-XX Special functions belongs in applied math, but I'm not sure where else it would go. CRGreathouse (t | c) 18:56, 13 March 2010 (UTC) I don't think we have enough "education" articles to make them worth a section; I would put them "general". Somehow, math education is not well represented on Wikipedia. For "history", I think the issue is that the current restriction of only one field means that most articles with historical aspects are listed under some other field. For example, I would think that an article on Gauss or Euler would count as both history and biography, but they would just be under biography right now. Similarly Euclidean geometry is under geometry right now. I don't know at what point things become historical, but if something involves Euclid I think it clearly is. — Carl (CBM · talk) 19:07, 13 March 2010 (UTC) Keep in mind that the MSC mainly covers research mathematics, but our encyclopedia articles are broader, also covering e.g. school textbook mathematics. So even if we wanted to go to a finer-grained system such as the MSC, the MSC itself would probably be inadequate: for instance, where does elementary arithmetic fit? Maybe 11-XX, maybe 97-XX, but neither is really a good fit. —David Eppstein (talk) 20:15, 13 March 2010 (UTC) I didn't include a "general" section because it's not relevant to the MSC; but I think it's really a good idea. I think we should have a "general" section which encompasses the current "basics" and "general" fields as well as all our education articles. Once we've corrected our embarrassing deficit of education articles, we can create a field for them. Regarding 33-XX Special functions, I was conflicted over that, but I didn't know what the right solution would be. One possible solution is to list it under every field, because there are special functions everywhere. I also considered making it its own field, since sometimes the same special function will turn up in seemingly unrelated contexts. I feel like putting it under applied math is kind of like giving up, because you know it's no good, but other people do it, so you know you'll get away with it... Ozob (talk) 20:59, 13 March 2010 (UTC) I agree that we need a "general" section as a catchall. For example, we have articles on journals, professional societies, and mathematics competitions. And television shows, I believe. I don't object to the current "basics" section, although it would be nice to expand it once we can have more than one field per article. For example, right now Pentagon is in geometry, but it would be nice to have that sort of thing listed in "basics" as well. — Carl (CBM · talk) 21:15, 13 March 2010 (UTC) Where would the article Differential analyser appear in the above classification? It is computer science but it isn't discrete mathematics. Bethnim (talk) 22:20, 13 March 2010 (UTC) I think Computer science should be in the applied section. Combinatorics should be a standalone category, and there shouldn't be a discrete section at all. Bethnim (talk) 22:33, 13 March 2010 (UTC) Difference and functional equations is fine being in the analysis section. Bethnim (talk) 22:35, 13 March 2010 (UTC) I don't think differential analyser is a mathematics article at all. It belongs to the history of computing. Why do you think there shouldn't be a discrete mathematics section? Ozob (talk) 22:51, 13 March 2010 (UTC) For one thing, although computer science is mostly about discrete computation, articles such as computable analysis and on continuous computation paradigms(http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.97.1895&rep=rep1&type=pdf) , are not discrete mathematics. Solutions to Difference and functional equations can be continuous functions. So the only real category left is combinatorics and even that isn't just about discrete mathematics (analytic combinatorics, infinitary combinatorics). Bethnim (talk) 23:01, 13 March 2010 (UTC) And many discrete concepts such as Discrete Calculus of Variations are direct analogs of notions in analysis and so should logically be categorized as analysis rather than discrete. Basically I don't think discreteness is a valid criteria for categorizing things. Bethnim (talk) 23:19, 13 March 2010 (UTC) Hmm. Where would you put graph theory, matroid, and coding theory? Ozob (talk) 00:37, 14 March 2010 (UTC) With coarse-grain I'd put graph theory and matroid theory in a combinatorics category, and put coding theory into applied. With finer-grain I'd put coding theory in Information theory and graph theory would have its own section. Bethnim (talk) 03:19, 14 March 2010 (UTC) One thing that springs to mind with the above list is that it seems to be tuned for research so it would be hard to categorize basic freshman calculus subjects. Where, for example, would Derivative, Catenary, and Ratio go?--RDBury (talk) 00:08, 14 March 2010 (UTC) Derivative would go under analysis, catenary under geometry, and ratio under general. (There isn't a general section in the list above, but consensus seems to be that we need one.) Ozob (talk) 00:21, 14 March 2010 (UTC) Analysis is one of our categories, it's not in the MSC. Perhaps Catenary would go under Special functions since cosh, or under differential geometry since it's defined by curvature. My point is that these more general knowledge articles are going to be ambiguous at best. In any case, it would be a good idea to do a test classification of a couple of dozen articles before deciding on anything rather than trying to decide based purely on intuition.--RDBury (talk) 11:56, 14 March 2010 (UTC) Ah, I thought you were asking a different question. I'm not particularly concerned about stuffing elementary articles into the MSC, because they won't fit; as we've already noted here, the MSC is intended for research. My intent was to use the MSC as a guide to classifying more advanced topics. But I don't feel like it really worked; I came up with roughly the classifications we have now, and I'm not really satisfied with them. I was struck with insight when I looked at the IMU list mentioned below: The IMU list has an entire section for Lie theory! In the MSC classification, Lie algebras are in 17Bxx, making them completely separate from Lie groups, which are in 22Exx. But you can't lump together all of 17-XX with 22-XX: For instance, finite dimensional algebras go in 17, topological groups go in 22, and the two subjects have hardly anything to do with each other (that I know of). So I feel like the MSC really doesn't capture this very well, and consequently no scheme based off of it will capture it either. Ozob (talk) 22:17, 15 March 2010 (UTC) I've taken the liberty of slightly tweaking Ozob's list above. In particular, I moved special functions to analysis as any special function I know of is related to some differential equation/integral/series (though, of course, any specific special function may be in many other fields). But in looking through the list, it's clear that the top-level MSC is both too fine and too coarse. I do think it gives a good understanding of which fields we need though, but I don't think it succeeds in allowing for a clear way to classify any given article. RobHar (talk) 02:56, 14 March 2010 (UTC) My main concern about Ozob's list is that it still has algebraic geometry under geometry. Is the idea to simply put both "algebra" and "geometry" fields on those articles? — Carl (CBM · talk) 11:28, 15 March 2010 (UTC) An alternative to the MSC list is the IMU list: http://www.mathunion.org/activities/icm/icm-2010-program-structure/ where Algebraic geometry, Lie theory and Dynamical systems each get their own sections. Although under the IMU scheme, recursion theory is part of foundations, and category theory is part of algebra, and Control theory and optimization art lumped together (but excluding combinatorial optimization). Bethnim (talk) 15:55, 15 March 2010 (UTC) I like that system a lot better, actually. We would need to tweak it a little, but I think it would be relatively easy to understand which section an article belongs in, unlike the current system. — Carl (CBM · talk) 18:27, 15 March 2010 (UTC) I like this system better, too. I should comment that I did really intend to lump all kinds of geometry and topology together: I feel like hardly anyone in algebraic geometry seems to take differential geometry seriously enough, and yes, I did feel like the articles that had both geometric and algebraic content could be put under both. But the IMU system is better, I think; In practice, commutative algebra and algebraic and complex geometry are yoked together very tightly, but their connection with differential geometry is pretty slim. Ozob (talk) 22:23, 15 March 2010 (UTC) ## Optimization algorithm Optimization algorithm is currently a redirect and until less than an hour ago, didn't even exist as a redirect. I found that quite surprising. Should there be such an article? Michael Hardy (talk) 04:26, 15 March 2010 (UTC) However, Optimization (mathematics) exists. What else should it be? Boris Tsirelson (talk) 10:09, 15 March 2010 (UTC) ## Gauss interpolation formula I am going now to create an article about equidistant interpolation but have a trouble with Gauss interpolation formula. Can anyone please verify this formula:[29]. I have tried but unsuccessfully.--MathFacts (talk) 10:17, 15 March 2010 (UTC) I thought that we had an article on difference equations, but it just links to recurrence relation which does not do the subject justice. There are some errors on the Springer page to which you linked, and the notation is not clear. If I were you I would look for a better source. JRSpriggs (talk) 08:13, 16 March 2010 (UTC) You might want to check whether the technique you are looking for is not already covered by interpolation. JRSpriggs (talk) 08:36, 16 March 2010 (UTC) ## Square (algebra) Square (algebra) is such a simple subject that it doesn't need attention from mathematicians. (?) So one might be tempted to think. I found it a horrible mess. I did some cleanup. At one point it asserted that the "general term" of the series $1^2 + 2^2 + 3^2 + \cdots + n^2 \,$ is $\frac{n(n+1)(2n+1)}{6}.$ Someone out there is challenged by the task of understanding what "general term" means. Should that be who writes this article? Which topics should be included is a question that needs to be considered by someone who has some competence. The present choice of topics is a bit weird, to say the least. Michael Hardy (talk) 18:42, 16 March 2010 (UTC) Square number is also in questionable shape, if not as bad as square (algebra). Michael Hardy (talk) 18:59, 16 March 2010 (UTC) My feeling is that Square (algebra), at least in its present form, reads too much like a chapter from a middle school algebra textbook and is too elementary in scope for an encyclopedia article. I would not be opposed to prodding of AfD-ing it. Nsk92 (talk) 20:22, 16 March 2010 (UTC) At the risk of being called overly critical (again), there are many subjects like this; too elementary for many mathies to take an interest so that leaves the field open for people to fill up the article with things they sort of remember from high school. One that I tried to clean up recently was Ratio but I only did about half of it. Badly written and uninformative aren't criteria for deletion though, unless a complete rewrite is in order.--RDBury (talk) 21:08, 16 March 2010 (UTC) ## Proposed deletion of Zenzizenzizenzic Discussion at Wikipedia:Articles for deletion/Zenzizenzizenzic (2nd nomination). Gandalf61 (talk) 11:29, 19 March 2010 (UTC) ## Professor of mathematics Professor of mathematics is a red link. Two articles link to it. Should we redirect it? Or create an article? Or delete the links? Or let our posterity decide six months from now? Michael Hardy (talk) 22:26, 19 March 2010 (UTC) De-link them. It's a phrase of ordinary English, understandable from its component words; shouldn't have an article. --Trovatore (talk) 22:28, 19 March 2010 (UTC) OK, I've done that. Now a question of no immediate practical import occurs to me. Is there any way to tell which articles formerly linked to a particular title? Michael Hardy (talk) 02:38, 20 March 2010 (UTC) No practical way that I know of. (In principle, of course, you could enumerate the history of every article in the encyclopedia.) This is the rationale, I think, for why you're not supposed to empty categories that you've proposed for deletion. --Trovatore (talk) 04:35, 20 March 2010 (UTC) ## Featured picture candidates part 4 User:Noodle snacks didn't do a nomination this week so I decided to try one. See Wikipedia:Featured picture candidates/File:Helicatenoid.gif. If you have some knowledge of differential geometry it would be helpful to check the caption; I tried to describe a local isometry in layman's terms, but maybe it could be done better.--RDBury (talk) 06:50, 20 March 2010 (UTC) ## Footer templates I made some changes to the Applied Mathematics template a month or so ago. I proposed similar expansion and organization of the Pure Mathematics template. (Following the earlier discussion (on the mathematics template's talk page), I suggest that somebody develop a "Basic mathematics" template. ThanksKiefer.Wolfowitz (talk) 17:50, 18 March 2010 (UTC) ### Industrial and applied mathematics I boldly changed the title to reflect the established usage of SIAM, British, and European organizations, and reflecting the problem that "applied mathematics" is often narrowly understood in terms of the grand British tradition of using analytic methods on problems in the physical sciences, etc. Kiefer.Wolfowitz (talk) 21:00, 18 March 2010 (UTC) ### Theoretical Computer Science This is probably the best venue for this discussion. There was recently a discussion on the talk page for the "P versus NP problem" article. There appears to be a consensus that Theoretical Computer Science is not in Applied Mathematics. With this in mind, I propose that the Applied Mathematics footer be modified. I would be bold and just make the change, but several articles would likely need to be modified to fully effectuate the change. And it might also be affected by the discussion Kiefer started above. Jwesley78 18:11, 18 March 2010 (UTC) Certainly, there is no such consensus. As the voice that opposes your visison of things perhaps the most, I would like to point out that there is agreement that there is overlap between these disciplines. While it may be agreed that statement that TCS is branch of applied mathematics does not reflect the situation, it has also been pointed out that on applied mathematics template was listed as branch of applied mathematics (apparently by a previous consensus opposite to one which is claimed), and it has also been pointed out that many theoretical computer scientists work at applied mathematics departments at places like MIT rather than in CS departments. To disregard all this and say that there is a "concensus" while there is ongoing controversy is awful misrepresentation of facts.Dlakavi (talk) 12:56, 19 March 2010 (UTC) Sounds good to me. CRGreathouse (t | c) 18:14, 18 March 2010 (UTC) Your "consensus" needs clarification, because many mentioned that theoretical CS is often housed in math departments, particularly in applied mathematics divisions, notably at MIT. There was consensus that Theoretical CS is not part of traditional British "applied mathematics", but that is hardly relevant to contemporary applied mathematics as defined by reliable sources, especially SIAM and the International Mathematics Union whose current President is Lovasz. SIAM publishes all of which are covered by the CS reviewing journal; all of these journals have significant overlap in editorial boards, author, references, with the leading CS journals. This argument could be strengthened by looking at the ISI list of journals in CS theory, but I assume you recognize that theoretical CS has a substantial overlap with applied mathematics. (IMHO, this overlap is much larger than the overlap with mathematical statistics.) SIAM cosponsors many of the main prizes in theoretical computer science (or at least prizes that prominently feature theoretical computer scientists): George Dantzig prize, the Fulkerson Prize, etc. The Theoretical computer science article plants the CS flag on many mathematical theories: Category theory, Graph theory, number theory, mathematical logic, etc.! (Why avoid the connection to mathematics now?) I believe that the previous editors are rightly concerned that Theoretical CS has much less overlap with the grand British tradish of "applied mathematics", with analytic methods (and some heuristics) applied to problems of physical science---But what about the extensive literature on formal power series and automata theory? Thanks Kiefer.Wolfowitz (talk) 19:09, 18 March 2010 (UTC) • The journals you list are not really journals in "Theoretical Computer Science". JoDaAM is close enough, but this argument is still not very strong. SIAM, like the ACM (Association for Computing Machinery), might be broader than its name would imply. Jwesley78 20:10, 18 March 2010 (UTC) • (I also made this comment here.) So there's no confusion, the question is not to what extent are TCS and Math related; they obviously are. In some ways, Computer Science (as a whole) is an "applied" branch off of Mathematics. The question here is specifically whether "Theoretical Computer Science" should be lumped into the category of "Applied Mathematics". TCS is the least "applied" of any field in CS. Many topics in TCS have no direct application. Since TCS is often not-in-any-way "applied", placing TCS within AM might be worse than placing another more applied field of CS (e.g., Artificial Intelligence) into AM. Jwesley78 20:04, 18 March 2010 (UTC) I made this comment there as well: :: Can we try to change the name of the template so that it is somewhat coherent and lists the topics of mathematical research that have strong ties to (empirical) science, engineering, and other concerns? I would suggest "Applicable Mathematics" or "Mathematics for Applications". Would either name be better and acceptable? Kiefer.Wolfowitz (talk) 20:12, 18 March 2010 (UTC) I changed the title to the established "Industrial and Applied Mathematics", (as noted above) because the others are less established and objectionable. Kiefer.Wolfowitz (talk) 21:02, 18 March 2010 (UTC) ### Computational mathematics Following the discussion, I removed "Theoretical computer science" and replaced it with "Computational mathematics", there being no short way to write "mathematics associated with theoretical computer science". Does this deal with the problem? (It may be useful to change the name of the footer to "industrial and applied mathematics", which is established at least).Kiefer.Wolfowitz (talk) 20:36, 18 March 2010 (UTC) I like this change. Some of the subtopics should be reassigned or removed; It's definitely a move in the right direction. Thanks, Jwesley78 20:42, 18 March 2010 (UTC) I object to the name "computational mathematics". Nobody calls it this; it's called "theoretical computer science". It is not Wikipedia's purpose to innovate. Calling this discipline anything other than "theoretical computer science" will only confuse people. Until we can sort this out, I've reverted. Ozob (talk) 00:41, 19 March 2010 (UTC) While I have no extremly strong objection to the change, it is misleading. Michael Sipser is theoretical computer scientist and is in the applied mathematics department at MIT. Many people who are important in theoretical computer science have degree from applied mathematics departments (Peter Shor is both a graduate of MIT applied math PhD program, and a professor there, and yet he is the leading person in quantum computation theory; even more traditional parts of TCS have such people alot). It is no more fair to say that this is part of mathematics as it is part of computer science. These are interdisciplinary areas, and being listed in more than one place is not inaccurate. Daniel Spielman is at applied mathematics department at Yale, has finished applied mathematics PhD at MIT and has been at MIT applied math department, and is one of the persons in Theoretical CS at yale (http://theory.cs.yale.edu/)... I am sure many more examples can be found. Dlakavi (talk) 13:07, 19 March 2010 (UTC) That's a silly argument. Departments have names that often result from tradition or accidents of university-specific history and politics. Go through the winners of the Gödel Prize and you'll find plenty of confusion. Avi Wigderson is at the School of Mathematics (IAS, Princeton). But he was in the computer science department at the Weizmann institute. Babai has a Ph.D. in math, works in a CS department, organizes the Budapest Semesters in Mathematics. Saks heads the Mathematics Graduate Program at Rutgers while Szegedy, also at Rutgers, is in the CS department. Razborov who was at Steklov (math) is currently in Chicago (cs). The thing is, the name of a department is not a great indicator. When my department switched its name from Computer Science Department to Software Engineering Department, I did not become more of an engineer. And my students now get degrees with a different name but they take the same courses, do the same research. (But the name change did allow us to hire three new profs) Pichpich (talk) 23:41, 19 March 2010 (UTC) It is not silly at all. If a math department employs a theoretical computer scientist, then, by definition, they believe that he is doing math. Or at least that what he is doing is awfully close to math, close enough that they think he fits in. We all agree—you gave examples yourself—that there are theoretical computer scientists in mathematics departments. (I know some.) Therefore some people believe that theoretical computer science is a branch of math, so the name is not inappropriate. Wikipedia does not introduce new or reshape old terminology; it follows the sources. If reliable sources say that theoretical computer science is a branch of math, who are we to argue? Ozob (talk) 03:40, 21 March 2010 (UTC) The original question was whether TCS is "applied" mathematics. We've strayed from the original question, asking instead whether TCS should be called "Mathematics" (of course it should). In my perspective, the very fact that the field is called "Theoretical Computer Science" should be enough to conclude that it's not "applied" in nature. Jwesley78 03:59, 21 March 2010 (UTC) ### What is "Applied Math"? Re: There are many subjects listed in the "Applied Math" footer that do not belong. Apparently there's a disagreement about which attributes distinguish "applied" from "pure" mathematics. This might be a good place to discuss it. Jwesley78 21:06, 18 March 2010 (UTC) Can we agree that the present template does reflect the IMU book's discussion of mathematics (pursued closely with empirical science and applications) and the applications featured by recent Fields medalists? (It does not try to represent the curriculum in Glascow for example.) Kiefer.Wolfowitz (talk) 21:41, 18 March 2010 (UTC) Look, there's a difference between these nav templates and explicit claims in an article about what is a branch of what. I don't really like nav templates and wouldn't mind if they were just deleted, but if we have to have them, it's not unreasonable to suppose that someone looking for ways to apply math would be interested in some CS-related links. That's not the same thing as making the frankly weird claim that P?=NP is a question of applied math. --Trovatore (talk) 21:52, 18 March 2010 (UTC) Nobody put the P?=NP question on the template. BTW, Smale and the Clay Foundation think that P=NP? is a central question of mathematics (after von Neumann's time), and Smale's judgement has been relied on by mathematicians for many decades; c.f. Vladimir I. Arnol'd acknowledgment in the Notices of the AMS article listed on the V. I. Arnold page. No, but this discussion didn't arise because of the template; it arose out of an edit war on the P?=NP page. I don't have any problem saying P?=NP is a question of mathematics. I don't think it's a question of applied mathematics. It strikes me as very far towards the theoretical end. Note that a proof (in either direction, although we all know that P!=NP so there's really only one candidate) would not necessarily have any applications at all to real-world problems. --Trovatore (talk) 22:37, 18 March 2010 (UTC) I am somewhat puzzled; would you please explain a bit, why a proof of P=NP (yes, if in this direction) would not apply to real word? Boris Tsirelson (talk) 07:07, 19 March 2010 (UTC) All it would (necessarily) do is tell you that there is a polynomial-time algorithm for (name your favorite NP-but-not-obviously P problem). It wouldn't necessarily tell you what that algo is. Even if it did, the bound might be n1000000 or something, which for practical purposes might as well be the Ackermann function. --Trovatore (talk) 08:20, 19 March 2010 (UTC) I see, thanks. Boris Tsirelson (talk) 11:46, 19 March 2010 (UTC) There is no consensus on the definition of applied mathematics or the existence of applied mathematics; see Vladimir I. Arnol'd acknowledgment in the Notices of the AMS article listed on the V. I. Arnold page. Kiefer.Wolfowitz (talk) 22:54, 18 March 2010 (UTC) No, of course there's not a consensus on the definition, and there's never going to be. That's not a problem. Putting a claim that a particular question is part of applied math, when actually very few workers in the field think of it that way, is a problem. --Trovatore (talk) 22:56, 18 March 2010 (UTC) Some of the more notable people interested in the question (P!=NP) - like Daniel Spielman of Yale - are actually at applied math departments. If a prize is offered by the major institution that wants to "disseminate mathematical knowledge" to the question, why is then wrong to say that it is an applied mathematics question too. Mathematicians (pure and applied), people form CS departments, logicians etc all pertain to this fundamental question. Dlakavi (talk) 13:32, 19 March 2010 (UTC) Which ones do people have a problem with? Of course any such split will be very fuzzy but I see no problem with classifying P≠NP as applied even if it probably will require some rather abstract logic for its solution if people don't just give up and accept it as an axiom. The distinction just makes it easier to find things. It's like the amount of information needed to describe a picture. The top is sky and the bottom is ground to start with. That doesn't mean a bird in the sky is blue or made of air. Dmcq (talk) 12:16, 19 March 2010 (UTC) ### Theoretical computer science: The Myths of a Discrete-Continuous Divide and a Pure-Applied Divide If applied means analysis then Theoretical computer science does overlap with applied. Not that the talking about pure/applied makes much sense. The applied math template should be merged with the main math footer template. Theoretical computer science considers both discrete and continuous computational processes, and both discrete and continuous input/output: • Continuous computability theory: Including P!=NP over R Many concepts in analysis have discrete versions giving rise to discrete analysis. See discrete mathematics for examples. So analysis shouldn't be contrasted with discrete. Analysis isn't just about limits or continuity, it is a collection of concepts and methods about functions and function spaces, be they discrete or continuous. Other topics often categorized as part of discrete mathematics: • Graph theory What is the most pure mathematics subject ? The queen of mathematics, number theory. What is the most applied ? Mathematical physics. Here are the Google results for "Number theory and physics" Number theory isn't concerned solely discrete objects: Transcendental numbers, Diophantine approximation, p-adic analysis, function fields There is no pure. There is no applied. And discrete mathematics as a distinct branch of mathematics is a nonsense. Bethnim (talk) 13:04, 19 March 2010 (UTC) ## Mathematical finance versus "Financial mathematics" Some editors use the "financial mathematics" rather than the standard term "mathematical finance". This seems as imperialistic as the use of "Bayesian mathematics" (sic.) to refer to Bayesian statistics (imho)! Kiefer.Wolfowitz (talk) 19:10, 20 March 2010 (UTC) ## Animation at Tesseract Another editor might be able to cast a fresh eye at Talk:Tesseract#New_Animations where User:Jgmoxness wishes to insert a new animation into the article but I'm objecting. Dmcq (talk) 21:35, 20 March 2010 (UTC) ## Mathematics template (footer): Here is the current template (footer): Would the following navigational-box template be an improvement, and useful for further discussion? # Apr 2010 ## Semigroup: independent views requested It would be helpful to have some independent views at Talk:Semigroup#Section_on_group_of_fractions on the validity and relevance of some material on the group of fractions of a semigroup. Thanks. Quotient group (talk) 20:40, 29 March 2010 (UTC) ## Featured picture candidates part 5 File:Helicatenoid.gif, with some small modifications, was promoted to Featured Picture. There aren't any current nominations for math, though there is a statistics one that is active.--RDBury (talk) 22:29, 29 March 2010 (UTC) ## Beppo-Levi space The new article titled Beppo-Levi space could use some work. In particular, it's a near-orphan; probably some other articles should link to it. Michael Hardy (talk) 03:15, 30 March 2010 (UTC) ## Laplacian Does our project have any preference on whether the Laplacian should be written as Δ or ∇2? I have noticed a trend in the past few months to replacing Δ with ∇2 in many articles, and I can't say that I approve. Sławomir Biały (talk) 17:22, 28 March 2010 (UTC) I haven't done any of such changes but personally I prefer ∇2 for its economy of symbolism, why do you dislike it? Dmcq (talk) 18:06, 28 March 2010 (UTC) I also prefer ∇2, though I don't feel strongly about it. The 2 emphasizes that the operator is second-order, and Δ is already used to represent the change in the value of a variable. It would be nice if someone could do a survey of some relevant textbooks to see which one is more common. Jim (talk) 18:30, 28 March 2010 (UTC) I prefer Δ. I'm used to seeing the Laplacian generalized to differential forms, where it takes the form dd* + d*d. (This leads to Hodge theory, of course.) While there are gradients and divergences in that formula, it isn't a gradient followed by a divergence, so I'm reluctant to embrace a notation which suggests that it is. Ozob (talk) 19:50, 28 March 2010 (UTC) This is not a question of preference, our notation should follow the accepted use. Sławomir, what are the articles where this has happened? Certainly, in PDEs and differential geometry, Δ is standard and ∇2 is rare at best. Besides the reasons mentioned by Ozob, the "usual" Laplacian has a square root, but it's the Dirac operator, not ∇. In vector analysis and some areas of physics the convention may be the opposite. By the way, Δ is both older and uses fewer symbols than ∇2, so it is in fact, more "economical". Arcfrk (talk) 22:39, 28 March 2010 (UTC) The ones I can find off the top of my head are at partial differential equation, Laplace operator, Zakharov system, and Hartree equation. Obviously, we have a lot of articles that use one convention or the other, but what I am mostly reacting to here is the (apparently) undiscussed migration from one convention to the other. Sławomir Biały (talk) 22:50, 28 March 2010 (UTC) Yes I go with the convention of not changing the convention that's used in an article if there isn't any good reason to do so. The person who went to the bother of writing an article should have some perks! Dmcq (talk) 12:49, 29 March 2010 (UTC) To Ozob: Borrowing from Klein–Gordon equation#Gravitational interaction, I think that $\Delta \psi = \frac{1}{\sqrt{-g}} \partial_{\mu} ( g^{\mu \nu} \sqrt{-g} \partial_{\nu} \psi ) = g^{\mu \nu} \partial_{\mu} \partial_{\nu} \psi - g^{\mu \nu} \Gamma^{\sigma}{}_{\mu \nu} \partial_{\sigma} \psi \,.$ Is that what you mean? JRSpriggs (talk) 13:01, 30 March 2010 (UTC) No. See Laplace–Beltrami_operator#Laplace–de Rham operator. This Laplacian acts on differential forms, not functions, and it's div grad plus grad div. For functions, the grad div term drops out, giving the equation you wrote above. I believe that de Rham, Differentiable manifolds, Griffiths and Harris, Principles of Algebraic Geometry, and Demailly, Complex Analytic and Differential Geometry each discuss this in detail. Ozob (talk) 22:58, 30 March 2010 (UTC) ## Semigroup: independent views requested It would be helpful to have some independent views at Talk:Semigroup#Section_on_group_of_fractions on the validity and relevance of some material on the group of fractions of a semigroup. Thanks. Quotient group (talk) 20:40, 29 March 2010 (UTC) ## Featured picture candidates part 5 File:Helicatenoid.gif, with some small modifications, was promoted to Featured Picture. There aren't any current nominations for math, though there is a statistics one that is active.--RDBury (talk) 22:29, 29 March 2010 (UTC) ## Beppo-Levi space The new article titled Beppo-Levi space could use some work. In particular, it's a near-orphan; probably some other articles should link to it. Michael Hardy (talk) 03:15, 30 March 2010 (UTC) ## Tagging number articles User:Notorious4life has recently bulk-tagged almost every number article from 2 (number) to 200 (number) with {{template:examplefarm}}, which says "This article may contain excessive, poor or irrelevant examples. " and adds the articles to Category:Articles with too many examples. I have invited the editor to come here to discuss their concerns about these articles. Gandalf61 (talk) 11:19, 30 March 2010 (UTC) • Actually, the mathematics examples within those articles are great and should be the focal point in the number articles. However, the number articles go off a terrible tangent of useless examples that are only included because they contain the number, such as "The electric battery-powered Lightning GT sports car, with a full charge, has a range of about 188 miles" being included in the 188 (number) article. Most of the examples listed in the number articles are absolutely terrible. I have brought this issue up before at Wikipedia_talk:WikiProject_Numbers#Too_many_examples on the Numbers WikiProject, which is where my problems rest. At first, the problems were met with agreement by the active projects members (of which I am not involved), but only two of the articles up to the number 200 have been fixed. The Number WikiProject has a vague and unenforced criteria for what constitutes a good example, and I intend to readdress the problems with them. In addition to the lack of inclusion criteria and pathetic examples, every one of those articles is unreferenced, poorly structured, and in need of much work. — №tǒŖïøŭş4lĭfė 11:50, 30 March 2010 (UTC) If you're referring to 8 and 9, the removal of retired jersey numbers and specific use of the number in sports did not have consensus, although policing the "notable people with jersey number n" sections to limit them is a pain, and the split had no consensus whatsoever. I quite agree with removing numbers with units unless notable in the popular culture (the entries in the former subdisambiguation 55 mph probably deserve notice). And I would think Wikipedia talk:WikiProject Numbers would be the appropriate place to discuss this. — Arthur Rubin (talk) 12:36, 30 March 2010 (UTC) not that it really matters, as long as pointers are there. — Arthur Rubin (talk) 12:37, 30 March 2010 (UTC) Yes, I only thought of Wikipedia talk:WikiProject Numbers after I had already posted here. So I put a pointer there instead. Gandalf61 (talk) 13:30, 30 March 2010 (UTC) • The tags seem to me inappropriate (the items in question are not "examples"). User:Notorious4life seems to have a fundamental problem with the way WP:WikiProject Numbers set up number articles, which isn't shared by the rest of that project. Each number article typically contains mathematical properties of the number, and a list of (non-mathematical) topics where the number occurs (because most people use numbers in a non-mathematical way, and may be looking up a number because they really want a pointer to some other article). Let's take 60 (number) as an example: it has a list of mathematical properties, uses of "60" in science (e.g. buckminsterfullerene C60 has 60 atoms), discussion of base-60 number systems, uses of 60 in religion, uses in sport, and a miscellaneous list. One or two items might be trimmed, but I'm happy with the article as is. I would agree with removing numbers with units only in the cases where these are approximations (i.e. I would retain 60 as a speed limit, but remove 60 where it is an approximation to e.g. 60.120978). I don't think any large-scale removal should occur, certainly not without broad consensus. -- Radagast3 (talk) 21:57, 30 March 2010 (UTC) ## The final stages of the collapse of civilization... What is this world coming to? I reverted this edit. Has anyone seen this happen before? Should we put in commented-out warnings in the hundreds of articles that use this locution? Michael Hardy (talk) 00:49, 31 March 2010 (UTC) The more complete the encyclopedia gets, the higher the ratio of silly edits to reasonable edits. Sooner or later we will have to slowly move towards something like the Citizendium model to keep most of the silliness out. But I guess we still have a few years before it gets really pressing. Hans Adler 01:00, 31 March 2010 (UTC) I disagree with this comment. Wikipedia was drowning in silliness six or seven years ago. Most of that isn't there any more. Michael Hardy (talk) 11:18, 31 March 2010 (UTC) Using "an Euler xxx" is more common on Wikipedia than "a Euler xxx" by 227 to 76. Furthermore, it's correct, since Euler is pronounced "oiler." "Corrections" which make things wrong are sadly common. -- Radagast3 (talk) 01:02, 31 March 2010 (UTC) The edit summary for this says it was via AWB; maybe that tool needs an exceptions table to keep track of things like "Euler". — Carl (CBM · talk) 01:12, 31 March 2010 (UTC) Good idea. -- Radagast3 (talk) 02:37, 31 March 2010 (UTC) Speaking of strange edits, here are two of them that replaced "work in (subject)" with "work CONCERNING (subject)" and "(verb) in (year)" with "(verb) DURING (year)": [30], [31]. I didn't want to revert because at least some of the corrections seemed good, yet many were downright silly. Arcfrk (talk) 03:36, 31 March 2010 (UTC) Go right ahead and revert silly edits! -- Radagast3 (talk) 04:10, 31 March 2010 (UTC) We may also need to put a comment like that into Probability theory, so that grammar geniuses stop "fixing" die → dice. And on the subject of bots, AWB and other automated tools: they frequently function as weapons of mass destruction. I can mention removals of white space and replacements of html based symbols with equivalent characters: &ge; with ≥ (both changes are invisible and hence useless for the readers, but very annoying for the actual editors who put them there), as well as "spelling fixes" like these: [32], [33] and "clean-ups" like this: [34] (there was a reason why only "riemannian" and "symplectic" were underlined, wouldn't you think so?). Is there a way to make people sign a damage control agreement before being allowed to use these tools to make the perpetrators at least AWARE of the consequences? Arcfrk (talk) 03:59, 31 March 2010 (UTC) We may need an exception list in some of these tools. -- Radagast3 (talk) 04:10, 31 March 2010 (UTC) AWB Typo rule list has been updated for Euler and Euler's. Rjwilmsi 07:28, 31 March 2010 (UTC) ## C rating status I updated the rating criteria so that the C rating is official. I also updated the maths rating tag so Category:C-Class mathematics articles will populate itself. VeblenBot still needs to be updated but Carl said that won't be hard. I think issues to consider for the future are the eventual fate of the B-Plus rating, and more generally whether we should maintain separate criteria for WPM ratings. As far as I know this is the only project (other than Statistics which uses ours) that uses it's own rating criteria; the others just link to Wikipedia:Version 1.0 Editorial Team/Assessment. My thinking is that if we are to have are own rating criteria then it should be because there is a consensus here that ours are better, as least for math articles. The current WP 1.0 criteria are (imo) confusing and inconsistent, so coming up with better criteria should be possible, but achieving consensus may prove problematic.--RDBury (talk) 10:26, 31 March 2010 (UTC) ## Superscript slash subscript Part of Wikipedia:Manual of Style (mathematics) tells us to only write fractions in styles like 1/2 and $\tfrac{1}{2}$ in mathematics articles. But there was an attempt to change it today to explicitly condone 12 style as well, a style that EmilJ and I have been fighting in some recent changes on Riemann hypothesis. See ongoing discussion at Wikipedia talk:Manual of Style (mathematics)#Fractions. —David Eppstein (talk) 22:29, 31 March 2010 (UTC) ## Discrete Math Category Why do we have a Category:Discrete mathematics ? Surely this is just as absurd as having a Category:Continuous mathematics containing things like euclidean geometry, sine function, real numbers, Set theory, manifold, Continuous symmetry. And information theory which is currently in the discrete mathematics category could just as easily be in a continuous category. I propose deleting this category. Bethnim (talk) 12:11, 23 March 2010 (UTC) I suppose there is a point to the effect that combinatorics is a research-oriented classification, while discrete mathematics is more of a pedagogically-oriented classification. Category:Subdivisions of mathematics is the over-category of both, and defines itself as "Fields and other subdivisions of mathematics". Which doesn't rule out such a subcategory, if it is useful for navigation. Charles Matthews (talk) 12:53, 23 March 2010 (UTC) The collection of things that are included in the Discrete math category is kind of random, though. Maybe it should only have a few categories in it, with the articles all in more specific categories? —David Eppstein (talk) 15:43, 23 March 2010 (UTC) Apart from things like DIMACS and Discrete Mathematics (journal), that seems a reasonable suggestion. Charles Matthews (talk) 16:18, 23 March 2010 (UTC) Ok, I cleaned out the category and added a few other categories as subcategories of this one. —David Eppstein (talk) 22:49, 23 March 2010 (UTC) Nice work. Though I'm not entirely convinced number theory should be in this category. RobHar (talk) 23:38, 23 March 2010 (UTC) I wasn't sure about that either. I suspect a paper in number theory might not be considered in scope for the journal Discrete Mathematics, for instance. Feel free to take it out if you think it would be better not listed there. But on the other hand, I think some amount of elementary number theoretic sequences, such as the Fibonacci numbers and Catalan numbers, would typically be included in a discrete math curriculum, so if number theory as a whole is not listed then maybe parts of it should be? I tried looking at the one book on my office shelves with "discrete mathematics" as its title (an old one by Ross and Wright) and it includes recurrences, but not really anything else in that direction. On the other hand it includes more linear algebra and abstract algebra than I would have expected. —David Eppstein (talk) 00:06, 24 March 2010 (UTC) Cool. I think I'll remove number theory, but at least throw in elementary number theory (I might reorganize the number theory category as well). RobHar (talk) 02:11, 24 March 2010 (UTC) PS: As it stands, "integer sequences" is in "combinatorics" which is in "discrete mathematics", so the numbers you mentioned somewhat inherit the discrete category via their appearance in "integer sequences". RobHar (talk) 02:15, 24 March 2010 (UTC) I think many who replied did not understand the intention of Bethnim. This is not about whether discrete mathematics is much different from combinatorics (actually, I thought they were synonymous until I read their WP articles) or whether this or that topic should be included. Looking at Special:Contributions/Bethnim for the last day(s), I see what seems an effort to single-handedly wipe the notion of Discrete Mathematics off the Wikipedia (see also the section #Theoretical computer science: The Myths of a Discrete-Continuous Divide and a Pure-Applied Divide above). Sure there are notions that are straddle the discrete/continuous boundary, and not all computers are digital (though quite a few are), but this does not make the discrete/continuous distinction any more invalid than pure/applied mathematics or even mathematics/computer science. Any subdivision of mathematics is debatable, but that does not mean that one may not make a tentative classification. I don't see what's wrong with saying combinatorics is a field of discrete mathematics (the adjective discrete was removed from the lede, as well as the category Discrete Mathematics), even if continuous techniques may at some places be used. I think some moderation would be in place. Marc van Leeuwen (talk) 15:49, 24 March 2010 (UTC) Marc you are over-reacting. I proposed deleting the category, but if it is deemed a useful category then so be it. As for deleting the adjective discrete from the lede of the combinatorics article, I didn't delete it - I just moved it further along the sentence. It just seemed weird to start of by saying "X is a branch of discrete mathematics" - this is tantamount to saying that all maths is continuous unless stated otherwise. Also every branch of mathematics contains branches of discrete mathematics - it's just that combinatorics is more associated with discrete than others. I was going to insert the word mainly which would give: "branch of mathematics concerning the study of mainly finite or countable discrete structures" but that didn't seem very grammatical. You mention moderation, and that is precisely what I've been doing. Previously the Discrete mathematics article said that "discrete mathematics is the language of theoretical computer science" - a sentence in definite need of moderation. The whole Discrete mathematics article gave the impression that theoretical computer science was only about discrete stuff, as did the main mathematics article. All the main areas of maths consider both discrete and continuous concepts but that's not the impression that the Discrete mathematics article used to give. Bethnim (talk) 21:00, 24 March 2010 (UTC) It is interesting though why does the term "Discrete mathematics" exist. Is it just a historical accident - because after Newton for the next few centuries continuous mathematics was the dominant theme. Well, I am definitely convinced of Bethnim's good intentions, but some edits seem a bit overly zealous, and push a particular point of view (that no exclusively discrete fields of mathematics exist). I agree that it is absurd to associate discrete mathematics exclusively with computer science, or to associate computer science exclusively with discrete mathematics. But there are a lot of mathematical and computer science problems that are genuinely discrete (which cannot be studied involving continuous variation of parameters), and I think it is somewhat biased to suggest that every area has discrete as well as continuous aspects; at some point the Discrete mathematics page looked a bit like it was trying to argue at all kinds of places that the notion is pointless. I've removed a claim about continuous graphs that seemed mainly there to provide such an argument, because there was nothing that could help the reader understand what was meant. I'm not saying no meaning can be given to "continuous graph", maybe it is something like the graph on R2 defined by points being at distance 1? Marc van Leeuwen (talk) 12:50, 25 March 2010 (UTC) I think almost any object can be continuized e.g. continuous graphs (Novel architectures for P2P applications: the continuous-discrete approach). Even continuous proof, infinite proof trees with continuous branching. If a discrete object doesn't have a continuous version it is just because noone has gotten round to continuifying it yet. Bethnim (talk) 18:10, 25 March 2010 (UTC) My take on this is that "Discrete mathematics" is a term which one will encounter during the course of studies. To ask Wikipedia what it is, and not get an answer because there is a philosophical standpoint that it is not meaningful or helpful would be disappointing.--Matt Westwood 16:29, 3 April 2010 (UTC) Who said anything about not getting an answer? The answer is given in the discrete mathematics article. The lead paragraph says that discrete mathematics studies discrete objects i.e. that do not vary smoothly like real numbers but have distinct separate values like integers. Further down, the article lists the areas of mathematics and describes which aspects of these subjects are discrete and which aspects are not. None of these areas is only concerned with discrete objects so it is important to describe which aspects of these subjects are discrete and which aspects are not. Bethnim (talk) 19:40, 3 April 2010 (UTC) Sorry, this was in response to the initial posting: "I propose deleting this category." I am coming down on the side of "anti" deleting this category. I misunderstood the thrust of the argument. But all said and done, the discrete mathematics article is all very well, but all it can do is give a general description of the topic, and give a list with short descriptions of its applicability. Okay as far as it goes but it's necessary to have a category in which one can browse further. And I believe it is advantageous to have such a category. --Matt Westwood 22:22, 3 April 2010 (UTC) —Preceding unsigned comment added by WestwoodMatt (talkcontribs) To inject my 2c worth, I'm very unhappy with some of the recent edits to Discrete mathematics, which seem to me not to accurately reflect the nature of the subject. I certainly do NOT support deleting the category. -- Radagast3 (talk) 03:08, 4 April 2010 (UTC) ## Cousins? Our articles on the physicist John Baez and the singer Joan Baez link to each other, each mentioning that they are cousins. Bernard Osgood Koopman's mother was a cousin of William Fogg Osgood; both were mathematicians. Should they similarly mention and link to each other? Michael Hardy (talk) 21:47, 1 April 2010 (UTC) If you can source it, and mentioning it doesn't unbalance the article in the direction of too much trivia and too little professional accomplishments, why not? For another example, see Greg Kuperberg and his parents, or for that matter the Bernoulli family. —David Eppstein (talk) 22:56, 1 April 2010 (UTC) I thought I'd seen it in one of the articles linked to externally. But now I can't find it. But I will eventually, unless someone beats me to it. Michael Hardy (talk) 03:06, 3 April 2010 (UTC) .... PS: One might also notice that the author of the obituary of William Fogg Osgood that is linked to externally was Bernard Osgood Koopman. Michael Hardy (talk) 03:07, 3 April 2010 (UTC) • A source is found here. John says, "My uncle Albert Baez showed me lasers, holographs and lots of physics experiments when I was a kid. Though mainly famous for being the father of the folk singer Joan Baez, he is a physicist who started out in optics, ...". Jwesley78 04:04, 3 April 2010 (UTC) Whoops. Sorry, nevermind. :-( I'll now look for an answer to the actual question. (I should learn to read whole comments, and not simply skim!) Jwesley78 04:48, 3 April 2010 (UTC) You're answering the wrong question. When I wrote that I thought I'd seen it in one of those externally linked articles, I was referring to the two people that this thread is about, not to the Baez's. Michael Hardy (talk) 04:30, 3 April 2010 (UTC) ## favourite occurrence of logarithms Guys, what's your favourite application/occurrence of logarithms? I'm just working on that article, which does have a few ones, but the more I read on the more crazy things I find, so I thought I should ask for broader input. Jakob.scholbach (talk) 18:20, 25 March 2010 (UTC) The logarithm on time scales ( Time scale calculus ) Bethnim (talk) 18:32, 25 March 2010 (UTC) Depending on how much you want to add it might be worth considering splitting the article or outsource parts to "main articles" such as "application of logarithms". At least with 61Kb already the article is getting rather big.--Kmhkmh (talk) 19:11, 25 March 2010 (UTC) Definitely decibels. Also, the Richter scale. My favorite mathematical application is as the inverse map to the universal cover exp : CC×. The logarithmic derivative is good, but possibly too specialized. Ozob (talk) 23:52, 25 March 2010 (UTC) Mine's that the bivector that describes the rotation between unit vectors m to n is the very neat log(mn), when calculated in geometric algebra: details at Plane of rotation#Bivectors. It's the generalisation of the log of a complex number including its geometric properties to higher dimensions.--JohnBlackburnewordsdeeds 00:17, 26 March 2010 (UTC) A few of my favorites: • Binary search, variants such as Fibonacci search, and their analysis. • The use of logarithms of complex numbers to transform plane symmetries that involve rotation and scaling (complex multiplication) into symmetries that are purely translational (complex addition). • Log-log plots. • The partial sums of the harmonic series (these come up quite frequently in the analysis of probabilistic algorithms such as quicksort, if you're looking for applications that are less purely mathematical). David Eppstein (talk) 00:36, 26 March 2010 (UTC) Just to add my exp(log 2)¢, to me the slide rule (already mentioned and depicted) and continuous compounding came to mind, although in both cases one could argue they are as much about the exponential function as about the logarithm. Marc van Leeuwen (talk) 09:03, 4 April 2010 (UTC) ## Navbox in Mathematics ### Old Navbox This is the current Navbox: # May 2010 ## Promotional essay articles prodded User:Gertbuschmann has recently written two essay articles, Mandelbrot and Julia set landscapes and Field lines of Julia sets, which seem to be (a) original research and (b) intended to promote the author's fractal art web site. I have prodded both. Gandalf61 (talk) 12:48, 20 April 2010 (UTC) Would it be appropriate to move some of the content to the image description page instead? Sławomir Biały (talk) 12:56, 20 April 2010 (UTC) The ideas aren't actually novel, so not really WP:OR. Properly referenced content could go into Julia set or fractal art. -- Radagast3 (talk) 04:42, 21 April 2010 (UTC) The mathematical content from Mandelbrot and Julia set landscapes is already in Julia set, in the section The distance estimation, which was inserted by User:Gertbuschmann at the same time as he wrote the promotional article . It still seems clear to me that the only reason for having a separate article is to promote Buschmann's web site and provide a gallery for his fractal art. The images are very nice, but Wikipedia is not the right place to promote them. As you have removed the prod, I think this article should now go to AfD. Does anyone else have views on this ? Gandalf61 (talk) 08:54, 21 April 2010 (UTC) If it went to AfD, I'd !vote to move any relevant content into Julia set (although it mostly seems to be there already) and into fractal art (where it certainly could fit well), adding references such as Peitgen & Richter, The Beauty of Fractals. I replaced the PROD on Mandelbrot and Julia set landscapes by a set of cleanup tags, but I've just noticed the author has removed them without discussion, as well as dePRODing the other article. -- Radagast3 (talk) 11:47, 21 April 2010 (UTC) His programs's got a rubbish UI as well. --Matt Westwood 18:26, 21 April 2010 (UTC) I can't see how that is relevant to this discussion. It's always worth remembering that authors of articles do have the technical ability to read this page, and that tact can make difficult situations less unpleasant for everyone involved. — Carl (CBM · talk) 19:39, 21 April 2010 (UTC) Update: The mathematical content of the two articles has now been merged into Julia set. What was left from one article has been deleted at the author's request, and the remains of the other have been usefied. However, User:Gertbuschmann has now created another new essay/textbook-style article at Images of Julia and Mandelbrot sets, which is as yet unreferenced. Gandalf61 (talk) 11:29, 24 April 2010 (UTC) More update: I have tried to explain the relevant Wikipedia policies to User:Gertbuschmann, but he has made no attempt to add sources or make any other improvements to Images of Julia and Mandelbrot sets. As he seems to have no intention of providing sources for his contributions, I have nominated the article for deletion - discussion at Wikipedia:Articles for deletion/Images of Julia and Mandelbrot sets. Gandalf61 (talk) 09:48, 30 April 2010 (UTC) ## Help request: Ronald Brown (mathematician) Hi. This article was up for deletion at WP:CP today as part of a WP:CCI. He seemed like a notable fellow, I had enough time, and the extensiveness of this particular problem was difficult to determine, so I've created a new article as a "start" (rather than deleting it). But I am not able to do him justice...or anything near, really. :) If somebody who has the background to review this (and this) could at least explain in what areas this fellow works, I'd be very grateful. :) --Moonriddengirl (talk) 20:12, 23 April 2010 (UTC) Looks like he mostly works in abstract algebra, particularly algebraic topology. 69.228.170.24 (talk) 09:55, 26 April 2010 (UTC) Actually he is a fairly well known category theorist. (Often "Ronnie", and there are other Ron Browns, none of which helps.) His contacts with Grothendieck put him on the map in terms of general interest. There is a lot of self-published stuff of his on the University of Bangor, and he is the sort of person about whom a decent WP article can be written, by sifting through. Charles Matthews (talk) 11:09, 26 April 2010 (UTC) Thank you! Would I be accurate and supported by his publications list if I revised the lead to read: "Ronald Brown is an English mathematician who works with category theory and algebraic topology"? Fortunately, I don't have to know what those are. :D --Moonriddengirl (talk) 11:14, 26 April 2010 (UTC) That would be OK - if he is somehow Welsh by identification I suppose we'll be told. Charles Matthews (talk) 10:18, 30 April 2010 (UTC) ## Math Overflow Does anyone here monitor the mathoverflow.net site? I happened upon it, and there is a fair amount of technical criticism there of our pages. Which could be helpful in a nitpicky, fact-checking way, certainly. (Amusingly they seem to have a site policy "don't start discussing whether WP is an RS".) Charles Matthews (talk) 20:27, 26 April 2010 (UTC) I check it every day. The problems discussed are generally at a rather high level, and most of our articles on that level are indeed lacking. I have seen several occurrences of recommendations of wiki's articles though. RobHar (talk) 00:28, 27 April 2010 (UTC) See Talk:Constant sheaf for a specific recent instance of criticism. RobHar (talk) 20:42, 3 May 2010 (UTC) Yes, that's a good example. Charles Matthews (talk) 09:04, 4 May 2010 (UTC) ## Till Tantau His bio is up for deletion. He is a math prof, although better know for his TeX work. (Taco Hoekwater is also up for deletion, should you care about TeX authors' bios.) Pcap ping 23:29, 3 May 2010 (UTC) ## nLab I've created a new stub article called nLab, and I've put links to it into ten other articles. Work on it. Michael Hardy (talk) 18:53, 4 May 2010 (UTC) ## LaTeX \sim rendering as tilde in html I've just noticed at the end of Random effects model#Simple example that the LaTeX \sim is being rendered in HTML as a tilde, e.g. $X \sim N(0,\sigma^2)$ – on my set-up at least that looks like X~N(0,σ²) but in a serif font in which the tilde is so small and high up as to look like little more than a wavy serif. Has it always done this? I know that I can force PNG rendering, but i would have thought that the authors of texvc should know that a tilde isn't an acceptable rendering of \sim. Is there somewhere I should report this? Qwfp (talk) 20:34, 3 May 2010 (UTC) Try this: $X \sim N(0,\sigma^2)\,$. I pretty much just add \, to the end of every math formula to avoid issues like this and to keep formulas looking consistent.--RDBury (talk) 21:31, 3 May 2010 (UTC) Please don't do that. If people want all formulae to be displayed as PNGs they can set their preferences accordingly. If a formula can be displayed reasonably well in HTML, then you should allow it to be. HTML works more widely and uses less bandwidth. You should only force it to display as an image if it doesn't work as HTML or it looks really weird compared to nearby formulae that can't display as HTML. --Tango (talk) 22:50, 3 May 2010 (UTC) The "really weird" thing is what I'm trying to fix. Nearly every math article is going to have some formula that can't be done in html, and having mixed formats on the page makes the article look like a ransom note. If I do see an article that's using html consistently then I'll leave it that way, but I don't see them often. For inline formulas I usually force html by just writing the formula in html, again so the mixed fonts don'tclash.--RDBury (talk) 13:55, 4 May 2010 (UTC) Yes, it should be reported as a bug in texvc. I can do that if you aren't familiar with http://bugzilla.wikimedia.org — Carl (CBM · talk) 22:04, 3 May 2010 (UTC) I'm not at all familiar with bugzilla, so I'd be most grateful if you could report this, Carl. Regards, Qwfp (talk) 22:17, 3 May 2010 (UTC) Sure. It's at bugzilla:23397 now — Carl (CBM · talk) 22:47, 3 May 2010 (UTC) Thanks Carl! I didn't realise html had a "sim" entity. So it should be possible to do better without resorting to PNG. Qwfp (talk) 22:56, 3 May 2010 (UTC) Even if it wasn't an entity, the sim operator has a Unicode point 223C, although not everyone may have the right fonts. But since HTML 4 is over 10 years old, anything in it should be visible to almost anyone. — Carl (CBM · talk) 23:01, 3 May 2010 (UTC) Experimental copy-pasting from List of XML and HTML character entity references: ∼ ≠ ~ ! Qwfp (talk) 23:10, 3 May 2010 (UTC) Actually, I was wrong: the current rendering is this character: 02dc. No wonder it looks so bad. I thought it was just a font issue, until I checked the bytes that actually make up the character that texvc uses. — Carl (CBM · talk) 00:05, 4 May 2010 (UTC) (ui) Is texvc being maintained at the moment? I've noticed that the MathML option has been "experimental" since I've started editing and there doesn't seem to have been any progress in getting it fully implemented. I just assumed that since most WP articles don't use formulas, the texvc issues are near the bottom of the list of priorities.--RDBury (talk) 13:56, 4 May 2010 (UTC) It is maintained; someone has already put in a patch for the bug about the \sim operator. On the other hand, the maintenance focuses primarily on bug fixes, for various reasons. I have been waiting for the STIX fonts to come out before asking about it. The way Wikimedia development works, anyone with the programming skill could work on the math system. There was a proposal for the google summer of code to rewrite texvc in python, but I don't think it was accepted. One option would be for Wikimedia to switch to jsMath instead of texvc for generating non-image TeX output. This is the system that MathOverflow uses, and it seems to be very actively maintained. — Carl (CBM · talk) 15:32, 4 May 2010 (UTC) Glad this has been patched so quickly. 'Scuse my ignorance, but how long is it likely to be before the patch comes into effect on en.wikipedia? Will we need to purge all the affected pages after is does? Qwfp (talk) 18:39, 4 May 2010 (UTC) I have been envying PlanetMath for their use of jsMath for quite some time. What are the odds that we could get this? It's funny that those smaller sites have the cool featuret because they are specialised, and we have to live the current situation that encourages coding all formulas in standard wikicode where feasible. Hans Adler 19:04, 4 May 2010 (UTC) It was very easy for me to get jsmath working with a local mediawiki install just now. The first step would be to convince the site admins (e.g Tim Starling) that it's worth adding. The actual code that would need to be written is trivial: all the work is in setting up everything on the webserver. It would also require testing to make sure it is able to render all the math that texvc output; I found a few issues already that would need to be fixed before it could be made live. But in principle this should be straightforward but time consuming. — Carl (CBM · talk) 20:26, 4 May 2010 (UTC) In my experience, the jsmath on the PlanetMath site takes a very long time to load. I'm not sure whether this has more to do with the site or with jsmath. Jim (talk) 22:21, 5 May 2010 (UTC) It looks to me as if the rendering happens with JavaScript on the client side, so the rendering delay would be a client side problem. I don't like the delay either, but it looks great. Hans Adler 22:38, 5 May 2010 (UTC) ## GA nomination Long and short scales has come up for GA review but so far no one has done a review. I'm not totally sure this is really a math article rather than linguistics but it's been put under math.--RDBury (talk) 19:51, 5 May 2010 (UTC) It is definitely linguistics, not mathematics. JRSpriggs (talk) 23:48, 5 May 2010 (UTC) ## Periods A notability tag has been placed at Period (number). Here's the Google scholar result periods author:zagier author:kontsevich. I think it's notable enough for its own article. Bethnim (talk) 09:48, 11 May 2010 (UTC) Probably. The definition is something a logician would come up with, though. The conjecture is of some interest, but is not formulated that clearly. The problem with taking the content of about one paper (I'm not clear whether that is a true description, but it expresses what I mean) and putting it forward as a Wikipedia topic, is that "notability" in the sense of being "serious" is not best judged by any metric applied to recent literature. At present, if we really lack the article on "period" in the sense of algebraic geometry (what we have is period mapping), in which the Kontsevich-Zagier ideas would naturally form a section on recent ideas, it is much harder to see what is going on. So I find the article too "presentist" (overly concerned with the buzz of current research) as it stands. Charles Matthews (talk) 10:19, 11 May 2010 (UTC) I looked over the list of the (numerous) papers citing the article "Periods" and found that there is an even spread over the past decade, not just "buzz of current research". There is even a paper from 1999 even though "Period" appeared in 2001! I think a separate page is justified given the article's influence. Tkuvho (talk) 10:28, 11 May 2010 (UTC) I still think Kontsevich–Zagier period conjecture would be a better title. If there is influence, it is apparently in the programmatic way certain parts of number theory fall into. Charles Matthews (talk) 11:55, 11 May 2010 (UTC) How many people referred to such a conjecture? Tkuvho (talk) 12:00, 11 May 2010 (UTC) The object itself that they introduced (namely, a reasonably "natural" intermediate field between Q-bar and R) appears to be of great interest, beyond the particular conjectures one formulates here. Tkuvho (talk) 12:02, 11 May 2010 (UTC) It is talked about that way - for example on mathoverflow.net; but who knows what is in print? I still think there is a certain problem about the formulation, which if you like is a writing problem. Just finding a way to define a countable field isn't specially notable at all, a mere exercise: the hypothetical decision algorithm is the interest, though it won't be within reach until transcendence theory improves remarkably. The paper was a preprint; it has found its way into a Springer book, so is notionally peer-reviewed. Again, if you isolate the conjecture, it is easier to feel that the issue of peer-review is not crucial. I have to say that I had similar issues in trying to reference motivic zeta function, sort of related in area/feel, for which the original source turns out to be a preprint nearly a decade old. We have the choice of awarding "notability" to some rather hypothetical mathematics, but I get worried when the original references are slender. (I'm not worried about the calibre of the mathematicians, but that isn't usually taken as decisive.). Charles Matthews (talk) 14:03, 11 May 2010 (UTC) I notice that some of the papers in the literature refer to this as Periods in the sense of Kontsevich and Zagier. This may be preferable to the current non-descript title. The term appears no longer to be a neologism, which is all that matters as far as wiki policy is concerned. Tkuvho (talk) 14:43, 11 May 2010 (UTC) (ec) (Before the comment adding Periods in the sense of Kontsevich and Zagier. I don't feel like rewriting my comments to refer to that.) As the one who added the notability tag, I'll make some comments before going on a Wikivacation. I may have added the wrong tag, but I have the following concerns about the article. This article first came to my attention when it was added to Template:Number systems. 1. I don't think "number" is the proper disambiguation, as most "periods" of a periodic function are numbers. Perhaps Period (Kontsevich and Zagier)?. (Although, if it is the same concept as the period of a rational system of differential equations, that might be a reasonable approach.) 2. The concept may be used (although not by me), but is this really a common use of the word "period" in Mathematics. And is "period" the most common term to refer to the concept? 3. Detailed comments: 1. Reference [2] (in the lede) seems to assume that the coefficients of "Igusa local zeta function" (which also appears to be different than Igusa zeta-function) is a "notion that algebraic geometers have studied since Riemann and Weirstraß." They (and the reviewers) may not be an experts in the "history of algebraic geometry", even if experts in "algebraic geometry". 2. The Newton-Leibniz formula seems to be a red-link; I'm not sure which formula attributed to Newton and Leibniz might be intended. 3. Speculation as to whether the reciprocal of a "period" is a "period" seems relevant. In all other hierarchies of numbers, larger sets have more closure properties than smaller sets. Here, the set of periods doesn't even seem to be a field. It almost certainly isn't algebraically closed, as we note that $\Gamma(p/q)^q$ is a period, without reference to $\Gamma(p/q)$. This section may be more relevant to whether it should be included in the template, rather than the article, itself. 4. I'm going to add the {{refimprove}} tag; the only inline references are in the lede, and there's no indication if the rest of the article is taken from those references (probably reference [1]). Please feel free to copy this to the article talk page. There doesn't appear to have been any comments there, and I probably should have brought it up there first. — Arthur Rubin (talk) 14:57, 11 May 2010 (UTC) Comments to Rubin. Period (Kontsevich and Zagier) improves what we have now; it is an idiosyncratic use. There is just one type of Igusa zeta function, AKAIK. The business of the reciprocal is not that relevant, IMO; it is in the nature of a remark that the set of periods being countable, the field they generate is also countable, but do they use the structure? The business of the fields seems to be lifted from the PlanetMath article referenced; should be rewritten. Charles Matthews (talk) 15:35, 11 May 2010 (UTC) R.e.b. has moved the article to Ring of periods. The tag was added, I guess because Template:Number systems linked to the article and Arthur Rubin objected to this because they are not algebraically closed or a field. Whether they constitute a "number system" is debatable I suppose, but I don't think they are any more or less a number system than any of the other things on that template. This is where the notability question comes in - are they notable enough to appear on that template? Bethnim (talk) 16:48, 11 May 2010 (UTC) I wouldn't include them on that template. I feel navigational templates of that kind exist on tolerance anyway, for cases where the category system is not the right solution for an appreciable set of readers. But calling the periods a "number system" is already too much of a stretch for me. Charles Matthews (talk) 17:41, 11 May 2010 (UTC) ## Discussion of the scope of Wikiproject Statistics As Wikiproject statistics is, in a sense, a daughter project of WP:Mathematics, your collective opinions about the scope of WP:STATS is requested at Wikipedia_talk:WikiProject Statistics#Clarification of scope?. Thank you. -- Avi (talk) 12:19, 11 May 2010 (UTC) ## Core articles We currently have a list of core mathematics articles at Wikipedia:WikiProject Mathematics/Wikipedia 1.0#Core Articles. It looks like it's been years since anyone has looked at this with a critical eye and the article ratings and statistics are out of date. My first question is whether we need our own list when there is already a (somewhat different) list at WP:CORE which is better maintained. There are also the WP:VITAL categories which seem to serve more or less the same purpose. If no one has a compelling reason to keep our list then I'll go ahead and replace it with a link to the math section in WP:CORE. If we decide to keep our own list, I think there should be some discussion as to what purpose it serves, how big it should be, and what should be the criteria for inclusion.--RDBury (talk) 16:57, 12 May 2010 (UTC) I replaced the section with a link. Our current tally of ratings for core articles is 5 B's and 1 B+.--RDBury (talk) 15:17, 14 May 2010 (UTC) ## Exaom See Exaom. So should we just "prod" this thing? Michael Hardy (talk) 05:20, 14 May 2010 (UTC) It is not mathematics, so I changed the category from Mathematics to Buddhism. Let them decide whether to delete it or not. JRSpriggs (talk) 07:08, 14 May 2010 (UTC) I prodded it. Sławomir Biały (talk) 11:12, 14 May 2010 (UTC) ## Opportunity for project to help save: Alwin Reinhold Korselt I recently removed the PROD on this one because I think there are sufficient sources out there to improve the article. As I don't have a clue about the history of Mathematics, maybe someone here can tackle this. Thanks--Mike Cline (talk) 15:05, 11 May 2010 (UTC) He does seem notable - contributions to logic and a controversy with Frege and Hilbert on foundations. (The contribution to number theory looks very much like an exam question I once did, though.) Charles Matthews (talk) 15:27, 11 May 2010 (UTC) I did some googling and was able to establish that he did indeed exist and he seems reasonably notable - but I didn't feel comfortably removing the notability tag until someone who really knows what they're talking about comes along. Instead I just put in an infobox so as that it'd at least look like a biography. --Paul Carpenter (talk) 12:44, 14 May 2010 (UTC) Actually, scrap that. I moved the article to a more sensible location (per the manual of style) and took away the notability tag. I figured that if his contributions are worth mentioning in other articles then he meets the first criterion in the professor test: "The person's research has made significant impact in their scholarly discipline...". However, there are still no sources for the purely biographical data such as his date of birth which are necessary for a decent biographical article. There is still a need for someone with specialist knowledge on this. --Paul Carpenter (talk) 16:01, 14 May 2010 (UTC) Interestingly (for some), the biographical data on Korselt is called "meagre"[35]. My German isn't quite up to reading what is said towards the end of that page. Charles Matthews (talk) 17:05, 14 May 2010 (UTC) That's an excellent find. It has appeared in a highly unorthodox experimental form – the floppy disk edition of the journal de:Wittgenstein-Studien – but appears to be reliable. Since my German is in better shape I will try to extend the article a bit. Hans Adler 18:18, 14 May 2010 (UTC) Thankyou very much and well done to all. I've taken away the "stub" and "fact" tags - it's now not a bad article at all. And to think that it was PROD'd just a few days ago! --Paul Carpenter (talk) 20:23, 14 May 2010 (UTC) I've copied a couple of the references, particularly the one in German, over to the German article so as to return the favour, since our version was originally copied over from theirs. Apparently non-logged in edits have to be approved before they are visible on the German Wikipedia, so I'm hoping that the tiny bit of German I had to use wasn't too awful. Paul Carpenter (talk) 09:37, 16 May 2010 (UTC) Thanks. The German Wikipedia doesn't like over-referencing and what they consider unnecessary footnotes, so I have fixed that. The accepted practice when you add a fact from a source that the average reader wouldn't want to consult is to give the source in the edit summary. Hans Adler 10:11, 16 May 2010 (UTC) ## NIST Handbook of Mathematical Functions ...is now published online, as the NIST Digital Library of Mathematical Functions. 03:38, 15 May 2010 (UTC) To Chzz: Thanks for the link. I always found the older printed version "Handbook of Mathematical Functions" to be very useful. Do you think we should have a separate article on this work, like we do on some other books such as Gravitation (book) by Misner, Thorne, and Wheeler? JRSpriggs (talk) 09:23, 15 May 2010 (UTC) I guess it's a bit early for that, but we can discuss it in the existing article Abramowitz and Stegun, and then either spawn it off once there is more to say about it or rename the article to Handbook of Mathematical Functions to make it clear that the article covers both. Hans Adler 11:42, 15 May 2010 (UTC) I see now that articles on both versions already exist, see Handbook of Mathematical Functions. Thanks to R.e.b. for improving the redirects. JRSpriggs (talk) 08:40, 16 May 2010 (UTC) ## Template:SpecialChars I have a funny sense of deja vu asking this, but I figured I should try to gauge the consensus again. Am I correct that {{SpecialChars}} does not belong on mathematics articles? I recently just removed it (for the third time) from Set (mathematics). Sławomir Biały (talk) 11:55, 14 May 2010 (UTC) The template is independent of topic of the article, IIUIC it belongs to any article which contains characters not rendering correctly in some popular browser setups. I've never had problems with missing characters myself, but I've seen people removing set-related symbols like ∪, ∩ from articles on the grounds that they do not see them, which would indicate that the template is appropriate on Set (mathematics) where these characters are used.—Emil J. 12:06, 14 May 2010 (UTC) Actually, as I have pointed out on Talk:Set (mathematics), there is no guideline at all regulating the usage of this template. Moreover, the template documentation flagrantly contradicts our own style guidelines. So I'm eager to see the template go, or be changed into something much less obtrusive (e.g., something that goes at the very bottom of the article rather than the very top). At any rate, this template is potentially something that, if your understanding is correct, would be put on just about every mathematics article. So it is obviously important for the project to get some clarity on precisely when it is appropriate (if ever). Sławomir Biały (talk) 12:24, 14 May 2010 (UTC) I guess it's not a matter of guideline, but of courtesy. I do not think it would concern "just about every mathematics article": more often than not problematic symbols are written in TeX rather than HTML in mathematical articles, and we probably only have to bother about high-profile articles (like Set (mathematics), I guess) which attract a lot of clueless readership. Anyway, I agree that the template is too obnoxious in the top right corner, (if used at all) it should better go elsewhere, preferably somewhere near the actual occurrence of the special characters it talks about.—Emil J. 12:43, 14 May 2010 (UTC) This should only be a problem with characters that don't show up correctly on some browsers. Looking at the Math and logic section of the special characters box in the Wikipedia edit screen, I see all of − × ÷ ⋅ ° ∗ ∘ ± ∓ ≤ ≥ ≠ ≡ ≅ ≜ ≝ ≐ ≃ ≈ ⊕ ⊗ ⇐ ⇔ ⇒ ∞ ← ↔ → ≪ ≫ ∝ √ ∤ ≀ ◅ ▻ ⋉ ⋊ ⋈ ∴ ∵ ↦ ¬ ∧ ∨ ⊻ ∀ ∃ ∈ ∉ ∋ ⊆ ⊈ ⊊ ⊂ ⊄ ⊇ ⊉ ⊋ ⊃ ⊅ ∪ ∩ ∑ ∏ ∐ ′ ∫ ∬ ∭ ∮ ∇ ∂ ∆ ∅ ℂ ℍ ℕ ℙ ℚ ℝ ℤ ℵ ⌊ ⌋ ⌈ ⌉ ⊤ ⊥ ⊢ ⊣ ⊧ □ ∠ correctly. On the other hand 〈 and 〉 just look like boxes to me so I'm thinking the TeX equivalents should be used instead. In general, the template shouldn't be needed at all in math articles because a TeX equivalent should be used instead of problematic characters, but the issue is what level of extended Unicode is to be considered problematic. It's not practical to use TeX every time we want to add a Greek letter or a minus sign. But people using popular browsers shouldn't need to load special fonts to read a math article. If we can agree on a list of acceptable characters (the named entities in List of XML and HTML character entity references might be a good place to start), and say that if it's not there then use TeX instead, the we should be able to avoid the use of the template altogether.--RDBury (talk) 15:56, 14 May 2010 (UTC) The angle brackets in your counterexample are named html entities: &lang; and &rang;. Also in my browser, these display correctly, and many of the other "acceptable" characters that you offer do not. So this suggestion, whatever its merits, still will not solve the problem that I had initially asked, since it seems unlikely that there is a symbol set that everyone will find satisfactory. Sławomir Biały (talk) 16:57, 14 May 2010 (UTC) What I had in mind was to start with the named entities a take out the ones that going to be a problem for a significant number of users. I'm still on Window XP so I suspect that the reason I can't see the angle brackets is my fonts are out of date. Are there still a significant number of people still using Window XP? WP:MOSMATH says that it's ok (more or less) to use anything on the list of named entities, so if we're both having trouble seeing all of them then perhaps some additional restrictions should be added. There are two extremes, use any Unicode character that exists even though many people won't be able to see them, or keep to ASCII and use up bandwidth with a PNG every time we use a minus sign. I'm hoping there is a reasonable compromise.--RDBury (talk) 18:09, 14 May 2010 (UTC) Just a side note, the second extreme is basically what MathWorld does. So a typical page has dozens of GIF images.--RDBury (talk) 18:45, 14 May 2010 (UTC) I'm using Win XP and Firefox and all the above symbols appear perfectly including the angle brackets. However in Internet Explorer 8 most of the symbols are boxes. So it's not a question of missing fonts or old operating systems. It's just that Internet Explorer is very very crap and Microsoft don't give a damn about mathematics. So I suggest that when people log on to Wikipedia they are met with a message saying that Wikipedia recommends Firefox for viewing special characters as Internet Explorer is hopeless. Open source projects should support each other. Bethnim (talk) 20:38, 14 May 2010 (UTC) What would be useful is if browsers could automatically download fonts from the web if they are needed. The web is nearly twenty years old - why do still have this nonsense ? Bethnim (talk) 20:56, 14 May 2010 (UTC) My (very dusty) IE at least shows − × ÷ ± ≤ ≥ ≠ ≡ ≈ ∞ ← ↔ → √ ∩ ∑ ∏ ′ ∫ ∂ ∆ ⌊ ⌋ ⌈ ⌉ which should be enough for most of the articles that use special math symbols. But for some reason it doesn't show union, ∈, ∅ or ⊆ which is probably the issue with the Set article. WP does have a Help:Special characters page which tells people how to properly set up IE to see these characters, but you have to know where to look and that's kind of the point to the template in first place. It would be nice for us to require people to read it when they log in to WP but keep in mind we're a minority here. So I guess the upshot is my idea won't work since it would be hard to do without basics like ∈. I only see three other options, either PNG everything like MathWorld, leave the special characters in and hope everyone reading a math article knows not to use IE (at least without changing the default font), or leave the template in. Maybe the solution is to make the template smaller. The way it was used in the Set article it was bigger than the diagram that was supposed to illustrate the subject, so it's a valid complaint that it's too obtrusive.--RDBury (talk) 01:36, 15 May 2010 (UTC) The CSS3 standard supports automatic font download,[36] and the feature already seems to be implemented by several popular browsers: Comparison of layout engines (Cascading Style Sheets)#Grammar and rules (including partial support in IE ≥4.0, if I understand the table correctly).—Emil J. 18:30, 15 May 2010 (UTC) In my opinion we have waited long enough for a good solution. The pseudo-LaTeX we are using looks horrible when printed and has silly size and baseline problems. Coding everything by hand in wiki code and with unicode is extremely tedious and error prone, doesn't give us enough flexibility, and causes problems with old browser setups. Articles keep getting changed from one style to the other and back. That's no wonder, because apart from different tastes we also have no less than six different options for how mathematics is rendered. I guess if we don't ask for an end to this madness, and do so several times, we are not going to get it. I think it should really be possible by now to create one, reasonable solution that doesn't require any options, works with the browsers of at least 95% of our users and has a simple fallback such as displaying pure latex source code for the others. I wouldn't consider it a problem if users of some browsers need to install a plugin (e.g. the MathML plugin for Internet Explorer) or download fonts, so long as the server pushes this as I have just seen on the W3C's MathML demonstration page when I visited it with Internet Explorer. Hans Adler 19:50, 15 May 2010 (UTC) A lot of these issues are already under discussion in the typography subproject. I'm really hoping that in the future MathML will be widely implemented enough that these problems can go away by themselves. Paul Carpenter (talk) 14:02, 16 May 2010 (UTC) There is already a MathML option under user preferences but the converter only handles the most basic formulas. To my knowledge, MathML and TeX are similar enough in syntax that it should be possible to write a full converter but someone with the skills (and the time) needs to do it and it looks like no one is volunteering. As I mentioned earlier, we're a minority on WP and I doubt this kind of thing is generally considered a high priority among the people at WikiMedia. (To put things in perspective, Numb3rs gets more than twice as many hits as Number.) I'm asking myself, if we did have an ideal system where math formulas were automatically converted to MathML, then how would we change the wiki-markup. One thing that would change is we wouldn't be kludging HTML and Unicode any more but writing even the simplest expressions in TeX (or whatever math markup language the future will bring). So maybe one thing we can do now is to stop relying so much on on the kludge and start using TeX more since the converter is supposed to be smart enough to convert to HTML on its own. One thing to try for the Set article would be to rewrite the formulas using ∪, ∈, ∅ and ⊆ to the TeX equivalents to see if the results are acceptable.--RDBury (talk) 17:56, 16 May 2010 (UTC) I tried a sample paragraph - HTML only (original): The key relation between sets is membership – when one set is an element of another. If A is a member of B, this is denoted AB, while if C is not a member of B then CB. For example, with respect to the sets A = {1,2,3,4}, B = {blue, white, red}, and F = {n2 − 4 : n is an integer; and 0 ≤ n ≤ 19} defined above, 4 ∈ A and 285 ∈ F; but 9 ∉ F and green ∉ B. TeX only: The key relation between sets is membership – when one set is an element of another. If $A$ is a member of $B$, this is denoted $A\ \in\ B$, while if $C$ is not a member of $B$ then $C\ \notin\ B$. For example, with respect to the sets $A = \{1,\ 2,\ 3,\ 4\}$, $B = \{\text{blue, white, red}\}$, and $F = \{n^2 - 4 :\ n \text{ is an integer; and } 0\ \le\ n\ \le\ 19\}$ defined above, $4\ \in\ A \text{ and } 285\ \in\ F$; but $9\ \notin\ F \text{ and green } \notin\ B$. When I view this with the 'Use HTML if Possible' option it renders as HTML instead of PNG, but there there still mismatches in the fonts, e.g. it uses serif which doesn't match the sans serif which is my default font, and it bolds most the plain text. Maybe some of the problems are due to my lack of skill with TeX (feel free to tweak the markup), but it seems like this issue should be a relatively easy fix and would have a better chance of getting done quickly than writing a complete TeX to MathML converter.--RDBury (talk) 18:53, 16 May 2010 (UTC) Hi, the LaTeX to MathML converter already exists since several years, it is called Blahtex. The principal obstacle to its introduction was that wikipedia is not mathml-ready, since it does not produce clean xhtml. The authors seem to have tired to wait and abandoned this project.--LutzL (talk) 11:57, 17 May 2010 (UTC) ## How to factor polynomials What shall be the fate of the new article titled How to factor polynomials? Michael Hardy (talk) 02:21, 17 May 2010 (UTC) .....and now I see that it's not a new article. It sat there for many months as a complete orphan (i.e. no other articles linked to it) until today, when someone added a category tag to it, thereby causing mathbot to notice it and add it to the list of mathematics articles, which in turn caused Jitse's bot to add it to this WikiProject's "Current activity" page, where I saw it listed. When I checked a few minutes ago the list of mathematics articles and a redirect were the only pages in the article space that linked to it. So maybe mathbot should search more extensively. If an article has certain words or phrases it could pick it up as a possible math article and call it to the attention of humans, who would then decide whether to add one of the math category tags. Michael Hardy (talk) 02:26, 17 May 2010 (UTC) Wikipedia is not a how-to guide. I think it should be transwikied to Wikibooks. -- King of ♠ 05:54, 17 May 2010 (UTC) Wikibooks is not a general dumping ground for everything we don't want. One would have to find a specific book that could profit from this material. Hans Adler 12:25, 17 May 2010 (UTC) But one shouldn't leap to the conclusion that it's a how-to article merely from the fact that its present title starts with the words "how to". Michael Hardy (talk) 10:42, 17 May 2010 (UTC) I've proposed merging into factorization of polynomials. Both articles are in deplorable condition. Michael Hardy (talk) 10:53, 17 May 2010 (UTC) Merging improving looks like good idea.--Kmhkmh (talk) 12:42, 17 May 2010 (UTC) ## Householder's method - input welcomed User:Gauge00 added a section titled "Another derivation of Householder's method" to Householder's method. I removed it, because the article already has a derivation section, and I do not think that the new section (a series of lengthy algebraic manipulations offering little or no insight) improves the article. Gauge00 reinstated the section with the justification "I think it is personal or individual preference to determine which one is more concise and clearer ... You are not the sole, unique reader, unique referee". So input from other editors is welcome at Talk:Householder's method. Gandalf61 (talk) 11:59, 17 May 2010 (UTC) ## Call to Arms for Wikipedia's sister projects Sometime around the summer of 2009 I had stopped developing any Wikipedia articles seriously. Fundamentally this was because I found I disagreed with the community about to what extent proofs should be covered in wikipedia articles. I don't want to start a long conversation about my reasons, suffice to say topics like Extreme value theorem which contains 3 proofs and effectively nothing "my older brother" could read just never said Encyclopedia to me. Also, User:Silly rabbit retired around that time I decided I needed a wikibreak to deal with my greif (he had mentored me into wikipedia when I first started editing Hilbert Transform). When I came back, I had this crazy idea that proofs belonged in books, and have since been active at Wikibooks. Many people here seem familiar with wikibooks, because we do get the occasional transwiki. But the fact is that, as far as mathematics goes, wikibooks is starved of editors. Maybe this is true across all of the subjects, but math seems especially hard hit. After reading a conversation at the village pump, I thought maybe it would be good to start a project specific discussion about ways to encourage cross wikimedia project collaborations. We do really well here getting very good articles, Is it possible to use that success to seed the sister projects? How do we encourage collaboration? I have often restrained from adding links to wikibooks the math there is frequently is such bad shape, but I am a loss at what else to do to let people know we exist. Thenub314 (talk) 19:43, 11 May 2010 (UTC) I think it would be nice if some of our activity could be more focused on the most important material for our customers audience. This should certainly include better development of high-visibility articles, but it could also include the creation of books or scripts. The German Wikiversity shows what is possible [37]: • Two different two-week preparatory courses for university maths. • An almost complete two-semester course on Linear Algebra. • An apparently complete one-semester Introduction to Algebra. • An apparently complete one-semester course on Algebraic Curves. • An apparently complete three-semester course on Real Analysis. • An apparently complete one-semester course related to Mathematical Finance. • An apparently complete one-semester course on Number Theory. Most of this material was created by just two editors. (On Wikiversity there is usually one responsible editor for each course.) Hans Adler 18:01, 12 May 2010 (UTC) Eek! The word "customers" really rubs me the wrong way. Arcfrk (talk) 21:53, 12 May 2010 (UTC) Better now? Hans Adler 00:07, 14 May 2010 (UTC) I couldn't agree with you more. That is certainly an example to live up to! I have recently finished converting a b:Linear Algebra text from LaTeX into a format readable on wikibooks. In nominating the book to be a featured book, it was suggested to me that the individual modules should link to wikipedia. And I have added a few random reciprocal links back to the book. Maybe we can have a cross-wiki collaboration, and see if we can a) improve some articles here on important linear algebra topics b) improve the book c) improve the wikiversity course... etc. Sort of a "Linear Algebra Month" where we try all try do donate a little of our editorial effort to our sisters. In hopes that our readers get a really first rate coverage everywhere they look. I would certainly be happy to do some editing at wikiversity and here (does wikitionary cover math jargon? I am not even well versed in what each of the sister projects do.) At least improved coverage. And maybe Linear Algebra is not the place to start, I only mention it because there is now a book that exists. I think by focusing on "core subjects" does a lot for speaking to the credibility and usefulness of all of these projects. Thenub314 (talk) 18:38, 12 May 2010 (UTC) I'm late but anyway. I'm still quite surprised that Wikibooks didn't really take off (you can't honestly say the project is working right now.) This is surprising given how expensive textbooks are and there is clearly a demand for textbooks in electric formats. (I don't buy the argument that people prefer dead-tree; if so, why is Wikipedia so popular?) I think one issue is that Wikibooks is suffering from negative network effects; i.e., poor contents attract few contributors which result in stagnation in content creation, a negative cycle. This happens to many user-generated content projects (e.g, Citizendium), and the major cause of this is WIkipedia. Any such projects must just have to compete with Wikipedia, and of course, they don't win. Ironically, Wikibooks is no exception; it has to compete with its bigger brother for contributors. Simply, Wikipedia has "good enough" coverage in math; for example, it already contains a lot of proofs, much more than any textbooks in Wikibooks. Maybe the mistake we made was to separate textbook creation from wikipedia. At least, in math, maybe textbooks are not dissimilar enough from encyclopedias. Why should an online encyclopedia (as opposed to print one) be forbidden from containing proofs, given unlimited disk space? (PlanetMath does contain proofs.) A student needs exercises or gentile guidance when learning new stuff for sure. But isn't providing that the function of Wikiversity? (Gee, I sound like thinking of customers.) Ideally, Wikibooks is a repository of proofs and other materials like formulae; but why can that role be filled by Wikipedia? I know this won't happen, but personally, I believe merging Wikibooks and Wikipedia is very good idea. It benefits both. Wikibooks would get huge boost in content creation, and Wikipedia finds a place to put contents that may be beyond the scope of the "paper" encyclopedia. But most important, Wikibooks and Wikipedia would no longer have to compete with each other. -- Taku (talk) 22:54, 15 May 2010 (UTC) I think any kind of "merge" between Wikibooks and Wikipedia is a bad idea; they serve different purposes. Anyways, here's my two cents: The reason I work on Wikipedia is b/c I *use* Wikipedia. (And I don't often use Wikibooks.) I agree with the comments above on this point, there's a "negative cycle": little content -> few readers -> few editors -> little content -> .... I think Wikibooks will eventually reach a "critical mass" and begin to be more heavily used. Wikipedia articles also have an advantage in that they are targeted to one topic. Writing a book (or chapter in a book) require more forethought, and are less amenable to editors who often begin their work saying something like "I've got 30 minutes free, I think I'll write something." 05:02, 16 May 2010 (UTC) Actually WP content on mathematics is very different from textbook standard content. As far as mathematics is concerned, encyclopedia articles are much easier to write than textbook chapters. And they are much worse to learn from, as far as a detailed grasp of the subject goes. (And that is true of other Internet materials on mathematics, too, sadly.) My comment about Wikibooks would be that typical mathematics textbooks arise from sets of lecture notes that are then written up more fully. There are some obvious conclusions to be drawn, about motivations and starting points. Charles Matthews (talk) 10:49, 16 May 2010 (UTC) "Writing a book (or chapter in a book) require more forethought" and more effort and a lot more patience... =S But I don't think on Wikibooks as a simple "repository of proofs and other materials like formulae": there is a lot of subjects which can benefit from a really carefully explanation in mathematics, and at Wikipedia there is no space for this (when we are explaining something, it is usually necessary to repeat the same thing in different words, maybe more than two times...). In a wikibook we can use all the didactics we could think of! And we can have two (or more) books on the same topic, but with different approaches (e.g. one explaining the concepts from abstract to particular while in the other everything comes from examples that are then generalized) I agree with Charles. My contributions at pt.Wikibooks in math are mainly based on lecture notes... Helder (talk) 21:20, 16 May 2010 (UTC) I agree that writing a traditional textbook is much more a daunting task than adding a piece of information to WP. But books in Wikibooks don't have to be typical textbooks; in fact, there is a book that is problem set or there is a book that provides solutions to widely used textbooks (e.g., Rudin). In theory, editing them should be as easy as editing WP. Charles Matthews mentioned lecture notes. I believe lecture notes belong to Wikiversity. Given the dynamical nature of wiki, it definitely makes sense to run courses in a parallel to development of course notes. (And our free license allows to create new sets of notes from old sets; mash-up, as the young people say.) By the way, today, students do use Internet a lot to do math homeworks; there are many sites that show you how to do typical Calculus problems. They are not good for in-depth grasp of subjects? Yes. But our mission is more modest than taking over the world (right?). I believe there is a gap in our offering; that is, Wikipedia and Wikbooks (and Wikiversity too ) don't provide this type of resources. (Gee, I sound speaking of "customers" again.) This gap arises in part because both Wikibooks don't want a calculus cookbook or a repository of proofs, say. -- Taku (talk) 21:53, 16 May 2010 (UTC) I find the above discussion very interesting. There are lots of reasons why wikibooks is struggling, and for mathematics lack of useful content is certainly the main one, this is closely related to the lack of active editors. These problems are not unique to wikibooks either, my brief glances at en.wikiversity show that for mathematics the same problems appear to exist. I suppose I am hoping that we could pick one topic, much like the collaboration of the month, and make the goal "let's improve the coverage of this subject across wikimedia". We might start small with a more specific project then I suggested before. Subjects like Solids of Revolution come to mind. We could list of a few articles from each site that could be improved on this subject. Examples from wikipedia might include: Solid of revolution, Pappus's centroid theorem. Wikibooks: b:Calculus/Volume of solids of revolution, the syllabus of v:Topic:Calculus (since I feel most calculus courses touch upon this subject in some way. But the wikiversity course doesn't touch it.) Commons: A animated image of first coarse disks, followed by successively thinner disks approaching the volume of the say a sphere. Would anyone be opposed to creating a small box to add to the project page near the collaboration of the month box? For what it is worth I am not that keen on a merging the projects either. But I do find Wikipedia:Books (or for a mathematics specific example Book:College Mathematics- Algebra) as something of a duplication of effort. But... "what can you do?" It seems like the lines between the projects get a bit blurry if you look too closely. For example I feel that the Reference desk, which is really about learning and understanding should really be a part of wikiversity, but this is not feasible for two reasons. First, wikiversity probably doesn't have the editor community to support it. Secondly it has a lot of momentum, lots of people do good work there answering peoples questions. People know to turn up there with questions and it would turn off editors to suddenly moved it. I suppose it falls under it seems it should fall under the "if it ain't broke..." philosophy, even if it is in a less then optimal spot. But enough of ranting about separate topics. Thenub314 (talk) 13:56, 19 May 2010 (UTC) ## Slightly off-topic Wikipedia_talk:Bot_policy#Proposal_to_softblock_Toolserver_IP_addresses. Since this project uses a number of bots, I thought I should let you know. Pcap ping 08:34, 18 May 2010 (UTC) ## Numerology and limitation of scope. Recently some articles were brought to our attention because they were needing sources, one of them was about a numerologist. Now I don't think that there's any doubt the biography of a numerologist should not fall into the scope of this Wikiproject. So I was thinking that as a precautionary measure - there should be some sort of statement about what this project and all the mathematical categories are not for. I was thinking that it should cover these things: 1. Numerology and related things that just aren't mathematics. Would be better suited to WikiProjects such as Sprituality or Pseudoscience. 2. Individual numbers, simply because there is Wikiproject dedicated to articles about numbers. 3. Statistical data (as opposed to the study of statistics itself), more or less for the same reason as individual numbers not falling within our scope. I don't think much of this has actually come up or caused a problem, but I think it should be made clear before it does. As I said, a precaution. If I were to go ahead with writing such a thing - should it be an official part of the project, or simply a wikipedia essay? --Paul Carpenter (talk) 12:54, 19 May 2010 (UTC) If we need such a statement, it should be part of this project, since it would be describing an internal matter (our intended scope) rather than an external one. But I am not (yet) certain that we need a clarification about this. One issue is that the type of people who think that this project is related to numerology are unlikely to actually read a long description of our scope before bringing an article here. So I don't know that a formal statement of scope would actually solve the perceived issue. — Carl (CBM · talk) 13:04, 19 May 2010 (UTC) I was thinking of it as an external issue - since it applies the categories and portals as well as the project. Also, in terms of application - like a lot of essays, it can be referred to easily in discussions and edit summaries e.g. "removed mathematics category per [some essay]". If it's not strictly needed here then I'll leave it as a personal essay. Paul Carpenter (talk) 14:16, 19 May 2010 (UTC) I'm not sure how the article got added to the list in the first place. It's not in any math related categories, it's not in List of mathematics articles and it doesn't have a maths rating tag. We might do well in general to have a better defined scope for this project, but I don't think that was the issue in this case.--RDBury (talk) 19:33, 19 May 2010 (UTC) It was a call for expert attention, actually. Perhaps just by saying it wasn't anything to do with us, we successfully answered that. --Paul Carpenter (talk) 21:56, 19 May 2010 (UTC) This strikes me as a solution in search of a problem. There is no realistic prospect that activity on articles about numerology and such is going to grow to levels that will be a serious distraction to the project. If an occasional one shows up in one of our lists, really, so what? On the other hand, we do occasionally have issues with editors who have restrictive notions of what constitutes mathematics (such as that mathematics is defined by a technique, such as formal proof) inserting those ideas in an insufficiently qualified form into articles. I would be much more attentive about not giving any encouragement to that sort of effort. --Trovatore (talk) 20:09, 19 May 2010 (UTC) Perhaps, it's just not something I'd like to see happen into the future. Like I said, I'm leaving it as a personal essay, I will however take all of that into consideration as I add to it - I think there is a lot that could be said on the topic of what constitutes mathematics in the context of Wikipedia. --Paul Carpenter (talk) 21:56, 19 May 2010 (UTC) ## Unreferenced Biographies of Living Persons The WikiProject Unreferenced Biographies of Living Persons (UBLPs) aims to reduce the number of unreferenced biographical articles to under 30,000 by June 1, primarily by enabling WikiProjects to easily identify UBLP articles in their project's scope. There were over 52,000 unreferenced BLPs in January 2010 and this has been reduced to 32,665 as of May 16. A bot is now running daily to compile a list of all articles that are in both Category:All unreferenced BLPs and have been tagged by a WikiProject. Note that the bot does NOT place unreferenced tags or assign articles to projects - this has been done by others previously - it just compiles a list. Your Project's list will be located at Wikipedia:WikiProject Mathematics/Unreferenced BLPs. The list of all other WikiProject UBLPs can be found at Wikipedia:WikiProject Unreferenced Biographies of Living Persons/WikiProjects. Doing a recursive scan of Category:WikiProject Mathematics articles (which is a different method than what the bot uses) I've found 5 articles: Your assistance in reviewing and referencing these articles is greatly appreciated. If you have any questions, please don't hestitate to ask either at WT:URBLP or at my talk page. Thanks,The-Pope (talk) 11:54, 18 May 2010 (UTC) I removed the tag from Mike Lesser, which does have references. Of the remaining ones, I think properly sourcing William Lawvere should be a priority. The other three (Glynis McCants, Luke Pebody, and Olivier Ramaré) seem to be on the borderline of notability. Sławomir Biały (talk) 12:13, 18 May 2010 (UTC) I don't see any reason why Glynis McCants and Olivier Ramaré should be considered notable, there is however extensive discussion on the talk page for Luke Pebody about his notability, so I have added speedy deletion templates on the McCants an Ramaré pages and am leaving Pebody for now. Aside from the need for sourcing there is also a need for general improvements to both the articles on Mike Lesser and William Lawvere articles. --Paul Carpenter (talk) 12:52, 18 May 2010 (UTC) The Pebody discussion was heated in 2003. I think we now take a different view of "famous for just one thing". PROD, or merge into necklace problem. Charles Matthews (talk) 13:51, 18 May 2010 (UTC) (ec) Yikes, Glynis McCants is a "numerologist" on Oprah. The speedy deletion was removed by someone else though. Perhaps removing association with WikiProject Mathematics would suffice? But shouldn't Olivier Ramaré be notable? He has published approximately 42 articles (rough count from 2 sections at "reprints" link from his webpage. The wikipedia article asserts he completed a proof of a simply expressed theorem (isn't that itself unusual? :) ). I removed the speedy deletion. I am not all up to speed on what makes one professor notable and others not, but couldn't this be developed rather than escalated to AFD? Unfortuneately i can't do that development though. --doncram (talk) 13:56, 18 May 2010 (UTC) I have removed our association with Glynis McCants - though the problem of it being poorly sourced and only borderline notable still remains, it is not (as participants in this project) our problem. Regarding what makes an academic notable, see the professor test. ----Paul Carpenter (talk) 15:07, 18 May 2010 (UTC) The article William Lawvere has several external links that qualify as "sources" for the purposes of determining if a BLP article is "unsourced". For example, the extensive BICM interview. Of course detailed sourcing is nice, but that article clearly not "unsourced". — Carl (CBM · talk) 14:11, 18 May 2010 (UTC) The lack of inline citations makes it difficult to verify any of the sources, but you're right in that it's not unsourced. That leaves Olivier Ramaré and we are done for now. Paul Carpenter (talk) 09:17, 21 May 2010 (UTC) ## Pythagorean theorem Some weird things are going on at Pythagorean theorem, Talk and here. People doubting that the theorem wouldn't be valid in R^n and such. Haven't got much time. Just added this ref to a simple proof. Someone might take a close look at the recent edits though... DVdm (talk) 12:21, 18 May 2010 (UTC) I find it hard to apply Hanlon's razor in this case and not simply assume that this is a transparent WP:POINT violation in order to "prove" a problem with our processes. Hans Adler 12:38, 18 May 2010 (UTC) Erm, Hans, I must say that I have no idea what you mean. What is "this ... violation"'? My little suggestion here, or the things going on over there? DVdm (talk) 12:52, 18 May 2010 (UTC) I meant some of the things going on over there, but I guess Carl is right. Hans Adler 13:09, 18 May 2010 (UTC) I think that we may both have been right about different things. It would be good for several people to keep the page on their watchlist for a while. — Carl (CBM · talk) 23:59, 18 May 2010 (UTC) Just to be clear: the issue is not with the "Pythagorean theorem" per se. Because a triangle is by definition contained in a plane, and every plane is isometric to the canonical xy-plane, the 2D form of the actual Pythagorean theorem is the only one that requires proof. What seems to be at issue on the talk page are various identities involving cross products that are sometimes labeled "Pythagorean". Of course we don't expect cross products to be defined in arbitrary n-dimensional spaces. Since that is already a side topic in the article on the Pythagorean theorem, just get the statements right and move on (which looks like what may be happening on the talk page). — Carl (CBM · talk) 13:01, 18 May 2010 (UTC) Note that two of the involved editors are on general probation. See Wikipedia:Arbitration/Requests/Case/Speed_of_light. TimothyRias (talk) 13:32, 18 May 2010 (UTC) Yes, look here, we are "WP crazies" now. DVdm (talk) 15:47, 20 May 2010 (UTC) The article itself seems OK, though. I'd let the comment on a user talk page pass as not worth much of a response. — Carl (CBM · talk) 16:03, 20 May 2010 (UTC) Indeed. Too bad it's so hard to track the changes. With brews making 10 edits per minute on the average, one has to wait until he's gone to sleep before one can get an idea of what has happened, let alone make a few changes here and there. When he's around, it's edit conflicts all over the place. Sigh. DVdm (talk) 16:29, 20 May 2010 (UTC) And David Tombe: "Clearly Pythagoras's theorem is a 3D theorem. It is a theorem about a 2D triangle in a 3D space.". Should people like that be allowed to touch articles? DVdm (talk) 17:19, 20 May 2010 (UTC) ## TOCright Today, I removed the {{TOCright}} template from the few math articles that used it (about 25 out of 24,000 articles). This template has the effect of floating the table of contents to the right side of the page. In a few cases, I replaced it with the {{toclimit}} template, to hide excessive subsections. Otherwise, I just removed it. I know of no argument why floating the table of contents to the right would be desirable in a math article, and all but a handful of our articles have never used it. The template was reinstated on material derivative. Could someone else look into that? I don't see any compelling reason for using the template there. — Carl (CBM · talk) 18:10, 21 May 2010 (UTC) It may improve readability (if moved down a line, into the #Names section). At least, on my screen, the TOC and the list of names don't interfere with each other. — Arthur Rubin (talk) 18:25, 21 May 2010 (UTC) It appears that this template should only be used with dab pages but there is very little in the template doc about in which pages it should be used. Perhaps this is really more an issue for Wikipedia:Village pump since I doubt any project wants TOC's to appear in random locations in their articles.--RDBury (talk) 18:31, 21 May 2010 (UTC) I agree there is very little guidance about when TOCright is actually warranted. I have left it alone on dab pages and similar pages, because I know it's often used on those (but I also don't know why). I can start a village pump thread later, if nobody else does. — Carl (CBM · talk) 19:55, 21 May 2010 (UTC) ## hyperbolic translations It Would Be Nice If Hyperboloid model, Beltrami–Klein model, Poincaré half-plane model and Poincaré disk model gave explicit formulas to convert coordinates among them. (Beltrami–Klein model does give conversions to and from the conformal disk.) —Tamfang (talk) 17:49, 20 May 2010 (UTC) Since the hyperboloid model is the most natural model, I think each of the others should explain how it is related to that one. Actually, the Klein model and the Poincare disk model already do this. The article on the Klein model says "The Beltrami–Klein model is obtained from the hyperboloid model by rescaling all vectors so that the timelike component is 1, that is, by projecting the hyperboloid embedding through the origin onto the plane x0 = 1.". The article on the Poincare disk model says "If we have a point [t, x1, ..., xn] on the upper sheet of the hyperboloid of the hyperboloid model, thereby defining a point in the hyperboloid model, we may project it onto the hypersurface t = 0 by intersecting it with a line drawn through [−1, 0, ..., 0]. The result is the corresponding point of the Poincaré disk model.". So the only one which is not already connected is the Poincare half-plane model. JRSpriggs (talk) 02:11, 21 May 2010 (UTC) Converting from Poincaré to hyperboloid is not quite trivial, though: I've just tried twice to derive a formula and got two different wrong answers! —Tamfang (talk) 04:39, 22 May 2010 (UTC) I assume you are talking about the Poincare disk model. The point $\langle t, \vec{x} \rangle \,$ on the upper sheet of the hyperboloid is mapped to the point $\vec{y} = \frac{\vec{x}}{1+t} \,$ in the Poincare disk. So $\vec{x} = \vec{y} (1+t) \,.$ A point on the upper sheet must satisfy $1 = t^2 - \vec{x} \cdot \vec{x} = t^2 - y^2 (1+t)^2 \,.$ Thus $0 = (1 - y^2) t^2 + (-2 y^2) t + (-1 - y^2) \,.$ Solving the quadratic equation gives $t = \frac{2 y^2 + \sqrt{4 y^4 - 4 (-1 + y^4)}}{2 (1 - y^2)} = \frac{1 + y^2}{1 - y^2} \,.$ Thus $\vec{x} = \frac{2 \vec{y}}{1 - y^2} \,.$ Is that OK? JRSpriggs (talk) 00:55, 23 May 2010 (UTC) ## Math in Moscow Math in Moscow has been prodded, i.e. deletion of the article will happen if no one objects for five days. What Do We Think? Michael Hardy (talk) 03:22, 21 May 2010 (UTC) Zpconn 20:09, 2 May 2010 (UTC) wrote (Talk:Math in Moscow):“Since the Budapest Semesters in Mathematics program has its own page, I felt Math in Moscow should have its own page as well.” The both noted articles (Math in Moscow and Budapest Semesters in Mathematics) are very strange and may be improved or removed. For example, “The IUM is located in a building in the very heart of Moscow. The address is 11 Bol. Vlasievskii per., a small quiet street near the historic Arbat and within walking distance of the Kremlin, the Bolshoi, the Rumyantsev library, the Pushkin Western Art Museum, and the cathedral of Christ the Savior.” (The article should not be Moscow guide)--Tim32 (talk) 07:51, 21 May 2010 (UTC) I think in both cases (Moscow and Budapest) the articles are very likely borderline notable, but it would be more reasonable to have articles about the respective mathematics departments and put the information there. Hans Adler 11:08, 21 May 2010 (UTC) I un-prodded it since it seems this will bear discussion. So: expand, or merge into another article, or delete, or what? Michael Hardy (talk) 21:53, 22 May 2010 (UTC) Certainly notable, even if not easy to source. Arcfrk (talk) 00:39, 23 May 2010 (UTC) ## Cartan's lemma I recently moved Cartan's lemma to Cartan's lemma (potential theory). There are enough things named "Cartan's lemma" that I feel explicit disambiguation is necessary, even if we don't currently have articles about the others. Any thoughts on whether a redirect of Cartan's lemma > Cartan's theorem would at this point be appropriate? Sławomir Biały (talk) 21:52, 22 May 2010 (UTC) I also should say that the new article Cartan's lemma (potential theory) is insufficiently developed that one can reasonably discern that it is about potential theory at all. It's not even clear to me that the result is stated properly. Sławomir Biały (talk) 21:56, 22 May 2010 (UTC) I have completely rewritten it from the cited source. It appears that the article had attached the name of Cartan to the wrong theorem! Sławomir Biały (talk) 22:06, 22 May 2010 (UTC) Was it at least the right Cartan? Arcfrk (talk) 00:42, 23 May 2010 (UTC) Yes :) Sławomir Biały (talk) 00:47, 23 May 2010 (UTC) ## Invariant subspaces I am not convinced that we need the newly created Category:Invariant subspaces. What do you all think? Arcfrk (talk) 00:49, 23 May 2010 (UTC) Update: in the process of populating this category, Kiefer.Wolfowitz has added a large block of references to several articles (I believe, this qualifies as WP:REFSPAM). I have reverted the most egregious instances (in Perron–Frobenius theorem, Invariant subspace, and Burnside's lemma), but I really question their value in other cases as well. Arcfrk (talk) 15:01, 24 May 2010 (UTC) The Perron-Frobenius theorem is discussed within the books on invariant subspaces by Aliprantis and Burkinshaw and by Radjavi and Rosenthal (simultaneous triangularization); it is also discussed by Lybuich (Banach representation of groups) and by various authors following de Pagter's use of Lomonosov's invariant subspace theorem to prove that compact positive operators have a postive spectral radius. Given this literature, Arcfrk's comment "category spam" was as impolite as Arkfrk's deletion was unwarranted. Kiefer.Wolfowitz (talk) 01:09, 23 May 2010 (UTC) "Category spam" is an objective reason for deletion removal, there is nothing personally offensive about it. Do you understand the purpose of the category system in the first place? Also, as Kiefer.Wolfowitz has started an edit revert war referring to this thread to justify his edits, an extra pair of eyes at Perron–Frobenius theorem will be greatly appreciated. Arcfrk (talk) 22:13, 23 May 2010 (UTC) Before casting stones .... Arcfrk first delete the membership of the article Perron-Frobenius in the category invariant subspaces with only the comment "category spam". So far, Arcfrk and the other editor have failed to reply to the reliable authorities (Aliprantis and Burkinshaw; Radjavi and Rosenthal), whose standard books devote at least a chapter to Perron Frobenius theory (c.f., Lyubich's books). It is not edit-warring to revert an un-motivated POV (and undue-weight) edit whose only explanation was a sneer. Now, Arcfrk cries about being reverted and cautions me not to edit war, when his pov editiing is contrary to the reliable sources, and he is guilty of edit-warring. The only comment pertinent to PF-Invariant subspace membership was that said link is trivial---which is POV contrary to the books mentioned, which have never been discussed by the 2 other editors. (2 editors on a Sunday night is hardly the consensus of the WP:Math project!) On the other hand, Arcfrk has criticized the earlier version of the category on invariant subspaces, but that is another matter: It would be edit warring to revert a nullification of the category, in contrast. Thanks Kiefer.Wolfowitz (talk) 22:34, 23 May 2010 (UTC) I would very much appreciate if you leave my name out of your incoherent rants, thank you very much. Here is a relevant policy: WP:AGF. I have reverted the inclusion of irrelevant categories (and again). This has nothing to do either with either WP:POV or WP:UNDUE (no content was added or removed). The fact remains that the burden is on you to demonstrate the relevance of all these additions. The primary purpose of references is to verify the content of the article. Most things in mathematics are related to each other in one way or another. That does not, however, mean that every book on matrix theory, operator theory, and who knows what else (Coxeter groups? Seriously?) that shows up on a google or MathSciNet search belongs to the reference list of this particular article. Similar remarks apply to categories. Arcfrk (talk) 03:01, 24 May 2010 (UTC) Humphreyes's Reflection Groups and Coxeter Groups discusses the Perron-Frobenius theory in Section 2.6. Please stop questioning my good faith and please stop personal attacks ("incoherent rants"). Please review your mistaken previous statements about the irrelevance of PF and invariant subspaces (apart from triviality); I'm pleased that you are moderating your statement now. However, you still have failed to address the reliable sources (Aliprantis, Burkinshaw, Rajdavi, Rosenthal, Lyuvich) linking the PF theory and invariant subspaces: These reliable sources should outweigh your POV. Thanks, Kiefer.Wolfowitz (talk) 15:58, 24 May 2010 (UTC) Given that this discussion has been sent to CfD, please put your further arguments there and there only. It is not up to this WikiProject to rule on the existence or renaming of categories. It seems that there are mathematicians on both sides of this discussion, so that it would all round be better to treat them all as colleagues. If you feel that they should do the same for you, then I of course agree. Charles Matthews (talk) 16:39, 24 May 2010 (UTC) I take your point, Charles. The references are a related issue that I felt was relevant for the math project (but not for the CfD discussion). Perhaps, I could have mentioned them separately. Arcfrk (talk) 07:42, 26 May 2010 (UTC) The category looks like a disjointed jumble to me. I'd vote to delete it. Ozob (talk) 02:24, 23 May 2010 (UTC) You two seem to edit mainly in algebra, rather than modern analysis and operator theory. Could you request an opinion from an analyst? See Henry Helson's book on Invariant subspaces to read about the Beurling factorization theorem (Hardy spaces), which is an abstract version of the Wold decomposition; this is also discussed in Young's book on Hilbert Spaces. Most of the topics are covered in Beauzamy and Lyubich's books. Kiefer.Wolfowitz (talk) 02:53, 23 May 2010 (UTC) I don't see what relevance my area of expertise has to do with this. I didn't comment on the articles in the category but on the category itself. Furthermore, Burnside's lemma, invariant subspace, linear subspace, and simple module are all algebra, and together they make up more than half the category. (I'll grant you that there's a brief mention of Hilbert and Banach spaces in invariant subspace, but it's quite short, and the article is clearly weighted towards algebra.) My central claim is still that the category is disjointed and jumbled. I would still vote delete. Ozob (talk) 03:06, 23 May 2010 (UTC) Journal Title - Israel Journal of Mathematics  Article Title - An extension of Burnside’s Theorem to infinite-dimensional spaces Volume - Volume 75 Issue - 2 First Page - 329 Last Page - 339 Issue Cover Date - 1991-10-01 Author - V. Lomonosov DOI - 10.1007/BF02776031 Link - http://www.springerlink.com/content/C1Q77462X50P4170  ### Deletion discussion I've nominated it for deletion. Please, cast your vote and explain the reasons here. Arcfrk (talk) 03:51, 23 May 2010 (UTC) ## Requesting project help on Cheung-Marks theorem This article is new and already up for deletion. Would someone from this project evaluate it for notability? Thanks.--Mike Cline (talk) 22:20, 23 May 2010 (UTC) ## Perron–Frobenius theorem: help requested The non-content part of that article is quickly becoming a dumping grounds for anything that might possibly be construed to be related to the topic. First it was loose addition of categories, followed by proliferation of references (continuing an earlier campaign by the same editor), and finally turned into bizarre personal attacks in this forum. I would be much obliged if some experienced editors can intervene. Arcfrk (talk) 02:21, 24 May 2010 (UTC) Several other articles in the currently contested Category:Invariant subspaces suffer from the same problem: refspam. I've reverted some additions, cf the thread above. Arcfrk (talk) 15:06, 24 May 2010 (UTC) Would you try to delete an article entitled "Perron-Frobenius theory", about generalizations of the finite square-matrix result, also? May I develop the material you deleted into a self-standing article? Kiefer.Wolfowitz (talk) 17:29, 24 May 2010 (UTC) I would have no objections to an article systematically explaining generalizations of PF theorem. I have said as much on the PF theorem talk page. Obviously, it would need to make sense mathematically. Arcfrk (talk) 07:31, 26 May 2010 (UTC) ## Knight's Tour FPC See Wikipedia:Featured picture candidates/Knight's Tour.--RDBury (talk) 20:24, 25 May 2010 (UTC) ## C-K Theory I removed some mathematics categories from C-K Theory because, although I can't really tell what the article is about, it does not look like mathematics. The categories were restored. I would appreciate any additional opinions on the categorization of this page. — Carl (CBM · talk) 21:17, 25 May 2010 (UTC) The article looks like a bunch of pseudotechnical woo if you ask me. Unfortunately Wikipedia has a high tolerance for this sort of nonsense. Sławomir Biały (talk) 01:45, 26 May 2010 (UTC) See also design methods, where there has been trouble in the past with proponents and ownership. I have now tagged C-K Theory for neutrality issues. Charles Matthews (talk) 07:41, 26 May 2010 (UTC) ## Angle brackets There is a discussion at Talk:Pythagorean theorem on the proper typesetting of angle brackets. At least one editor is advocating a blanket change in multiple articles to using less-than greater-than symbols (rather than the more proper 〈 〉 or $\langle,\rangle$.) Please comment there. Sławomir Biały (talk) 09:57, 26 May 2010 (UTC) The author was proposing to change just one section in one article (Pythagorean theorem#Inner product spaces). Note that the "more proper" 〈 , 〉 display as boxes on many (if not all?) systems with Internet Explorer. I tested it on 12 systems. None of them showed angle brackets. DVdm (talk) 10:13, 26 May 2010 (UTC) Yes, he had written "article section 'Inner product space'", which I had read as "article 'Inner product space'". My mistake. Sławomir Biały (talk) 10:38, 26 May 2010 (UTC) I was surprised this issue is not in WP:MOSMATH, if only to say that greater-than and less-than signs should be avoided. As always, the issue is always with fonts, not with browsers. But finding the right settings can sometimes be difficult. — Carl (CBM · talk) 11:34, 26 May 2010 (UTC) The above & lang ; or < math \ langle in Sławomir Biały's post appear as boxes but the following appear ok on my browser: 〈 and 〉 Bethnim (talk) 11:45, 26 May 2010 (UTC) We just had a discussion on this in #Template:SpecialChars, not that anything was decided really. For inner products I'd say avoid the issue by using a⋅b.--RDBury (talk) 15:05, 26 May 2010 (UTC) But what for Bethnim is ok appears here (firefox/linux) as boxes for unicode 3008/3009, which are spacing characters for asian text, not mathematical symbols.--LutzL (talk) 15:26, 26 May 2010 (UTC) ### MOSMATH I have started a section at Wikipedia_talk:Manual_of_Style_(mathematics)#Inner_products to discuss this. I think the MOS should give some concrete guidance to avoid using less-than and greater-than signs, just as it has concrete guidance on using &minus; instead of a hyphen or using &times; instead of the letter "x". — Carl (CBM · talk) 12:46, 26 May 2010 (UTC) Note, however, that due to massive drive-by robotic "typo fix" edits, many &minus; etc commands are replaced by "equivalent" html characters, the problem with it, of course, being that many new or inexperienced editors, who oftentimes pick up style by example rather than by reading MOS, never see the proper way to typeset things. Arcfrk (talk) 03:35, 27 May 2010 (UTC) ## Merge proposal for Hinge theorem to Law of sines I'm not a mathematician, so I invite experts to participate in this discussion which is at Talk:Law of sines. Cheers. Rodhullandemu 20:22, 27 May 2010 (UTC) ## "Holonomy" and "Holonomic" ...are two separate articles. Should they be? Even if they're about entirely different concepts (I haven't looked) shouldn't their names make more sense than that? Michael Hardy (talk) 15:57, 27 May 2010 (UTC) Although ultimately related, the two notions are completely different. Separate articles are definitely appropriate. Sławomir Biały (talk) 21:08, 27 May 2010 (UTC) Agree. Holonomy is a mathematical notion, "what happens when we return back". There is, for instance, holonomy pseudo-group of a foliation. And in the holonomic article it is spoken on the so-called holonomic systems in physics: those that do not have "velocity direction" restrictions. (For instance, while skiing with ice skates, one can go _only_ in the direction they point, so the possible velocities space does not coincide with all the tangent space to possible positions -- and this "system" is hence non-holonomic.) --Burivykh (talk) 02:01, 28 May 2010 (UTC) In any case, the material in Holonomic should be split in separate articles since it has material about three or four unrelated subjects. In general, it's not good idea to have articles with adjectives as titles since it often leads to this sort of thing.--RDBury (talk) 19:09, 28 May 2010 (UTC) ## STIX fonts v1.0 released Greetings, old friends. I ceased participating in Wikipedia, and WPM in particular, some time back, with a heavy heart. One reason, among many, was the total disinterest of the software developers in decent mathematical typography (read: no MathML nor incorporation of something like blahTeX). That has not changed. But one long-awaited major milestone has been reached elsewhere, which has prompted me to post here, so that all the mathematicians and friends who follow these discussions can benefit. Year after year the STIX Fonts project has posted notice after notice telling us that a complete set of fonts for mathematics was right around the corner. Never once has a projection date been met, nor closely approximated. Today, the vaporware precipitates into a solid release. The website reads: STIX Fonts Version 1.0 Released The initial set of 23 OpenType fonts is now available for download • Full Download (2.6MB Zip file) • License as Text File or PDF File • Documentation (PDF file) • Press Release Additional documentation for this release is still being worked on and will be posted to this site as soon as possible. Version 1.1, which will include fonts packaged for use with Microsoft Office applications, is scheduled for release by the end of 2010. Version 1.2, which will include Type 1 fonts for use with LaTeX, will follow in 2011. This site was last updated on 28 May. The next update will occur mid-June.  Please, put these open licensed fonts to good use, here and everywhere. (My glyph test page, apparently long forgotten by most editors here, may be of help.) Best wishes. --KSmrqT 22:03, 28 May 2010 (UTC) It's good to hear from you. I have been anxiously awaiting these as well. Like Duke Nukem Forever the development process for these started in 1997 [38], so it was a race to see which could remain vaporware longer. I installed the fonts just now, and almost every character on your glyph page displays for me. On a modern Linux system, installation usually just means copying the .otf files to ~/.fonts and restarting your web browser. Firefox (at least) automatically falls back on them for characters not in your default font. — Carl (CBM · talk) 23:15, 28 May 2010 (UTC) Damn. Never thought I'd live to see this. Algebraist 23:09, 29 May 2010 (UTC) ## Vanity page? Darij Grinberg looks very dubious to me. It's unlikely that it passes any reasonable notability test. "References" are half-broken links to blogs. Prod or AfD, perhaps? Arcfrk (talk) 11:05, 23 May 2010 (UTC) Definitely doesn't look notable. I'm not certain about Encyclopedia of Triangle Centers either, which seems to be the only given claim to notability. --Paul Carpenter (talk) 11:46, 23 May 2010 (UTC) I think ETC should be considered similarly to OEIS in this respect: a very useful database for a specialized type of mathematical search, but being in there does not confer notability. We can use it as a source for articles on triangle center topics that have enough other sources to be notable, but not as evidence of notability for those topics. —David Eppstein (talk) 17:39, 23 May 2010 (UTC) Yeah. I also don't see much evidence for notability as an academic. And since it's a WP:BLP the article really needs some sources. 18:56, 23 May 2010 (UTC) Prodded. Sławomir Biały (talk) 23:22, 23 May 2010 (UTC) The article has been unprodded, on the basis that Grinberg won a medal at the International Mathematical Olympiad and that makes him notable (does it?) - AfD maybe? --Paul Carpenter (talk) 15:10, 30 May 2010 (UTC) A gold medal seems to put you in the top 10% of participants, but I wouldn't reckon it is any serious evidence of notability. Charles Matthews (talk) 15:47, 30 May 2010 (UTC) Looks like a candidate for AfD. An IMO gold medal does not automatically make the subject notable. In fact, the article on four-time Putnam Fellow Arthur Rubin was not generally considered to be notable on the strength of his Putnam winnings alone (his Erdos number 1 ultimately seemed to tip the scales), and the Putnam is a much more exclusive award. Sławomir Biały (talk) 19:20, 30 May 2010 (UTC) Now on AfD: See Wikipedia:Articles for deletion/Darij Grinberg. Please direct your comments there. Sławomir Biały (talk) 19:31, 30 May 2010 (UTC) ## Multiple move for coordinates We currently have a collection of articles dealing with the various systems of coordinates. The names of these articles are are not consistent, for example Cylindrical coordinate system and Parabolic coordinates. The "X coordinates" format goes against WP naming conventions which say that a singular nouns are preferred (See Wikipedia:SINGULAR). Therefore I propose that the articles whose names currently end with 'coordinates' be moved, so for example "Parabolic coordinates" would become "Parabolic coordinate system". There are quite a few articles like that and not all fall under WPMATH, so this would be done a few articles at a time. Are there any objections to such a move?--RDBury (talk) 20:24, 29 May 2010 (UTC) I don't care either way, but I don't agree with your rationale. WP:SINGULAR mentions some common sense exceptions, introducing them with "exceptions include", andcoordinates seems to fit here quite nicely. I would agree with renaming to "coordinate system" under the rationale that that doesn't superficially look like a breach of WP:SINGULAR and is therefore more elegant. But I would hate this to be yet another precedent for ignoring common sense in the interpretation of policies. There are probably other cases of unavoidable plurals, with no elegant singular alternatives. Let us not contribute to their being renamed simply because they don't fall under the few exceptions that are mentioned explicitly. Hans Adler 20:45, 29 May 2010 (UTC) I'm not trying to set a precedent for changing all articles with plurals in the titles. In this case the convention agrees with common sense since the articles are about coordinate systems rather than individual coordinates. A coordinate is just a variable unless in the context of a coordinate system.--RDBury (talk) 23:26, 29 May 2010 (UTC) PS. A good example of what you're talking about is Simultaneous equations. I agree that it would make no sense to change it to "Simultaneous equation".--RDBury (talk) 23:31, 29 May 2010 (UTC) On another hand, "System of simultaneous equations" is arguably more accurate. —Tamfang (talk) 00:46, 30 May 2010 (UTC) Consistency is to be preferred, and I think the proposed direction is the correct one. The coordinates naming system is a bit informal. - 2/0 (cont.) 01:16, 30 May 2010 (UTC) Simplicity is also to be preferred. "System of simultaneous equations" is less likely to be searched for or linked to than is "simultaneous equations". Michael Hardy (talk) 02:49, 30 May 2010 (UTC) I agree. I don't see that adding the word "system" to the end of one of these title conveys any useful additional meaning. I think the shorter titles are better. K.I.S.S.David Eppstein (talk) 16:32, 30 May 2010 (UTC) "System" does convey meaning. Coordinates is just the plural of coordinate. In the plane, there are are multiple ways to select coordinate axes and choose a scale of measurement. The term "x-coordinate" does not have and meaning until these choice are made. Most of the time the choice is made implicitly and we say "coordinates" as a shorthand for "coordinate system", but article titles should be the correct names, not the everyday abbreviations. The most commonly read articles already use "system" in the titles, it's just there are a bunch of more obscure articles that don't.--RDBury (talk) 04:06, 31 May 2010 (UTC) # Jun 2010 ## Template:Mathematics portal FYI, {{Mathematics portal}} has been nominated for deletion. 70.29.210.155 (talk) 05:20, 24 May 2010 (UTC) To clarify a bit, someone nominated a whole bunch of templates that have been superseded by {{portal}}. Math is one of them.--RDBury (talk) 19:57, 24 May 2010 (UTC) To clarify even a bit more: that someone unlinked these templates, then nominated them for deletion as "unused". After an outcry by other editors, the wikiprojects affected began to be notified. Arcfrk (talk) 07:57, 26 May 2010 (UTC) This template has now been replaced by {{portal|Mathematics}}. Thanks! Plastikspork ―Œ(talk) 03:51, 2 June 2010 (UTC) ## Links and articles for the uninitiated There are many people in this world who are ready, willing and able to learn about mathematics. Wikipedia should be a great place to do this. It isn't. Math articles in Wikipedia are like a walled fortress: if you aren't already on the inside, there's no way in. Other highly-technical areas of study (like genetics, for example) are easy to navigate. Unfamiliar terms link to other articles that either clear up the mystery or at least set the reader on a path to understanding the material. Disambiguation pages don't slow you down too much because the context of your inquiry is usually pretty clear. With math, the problem is the symbols. They are often left undefined, which may be fine if you are aware of certain chalk-saving conventions used in math classes, but this is Wikipedia, the place where people go, who DON'T already know. I'm not asking anyone to start dumming down all the math articles. It would just be nice if when a symbol is used that the non-mathematician doesn't know how to read (let alone understand) if it could be linked to an article specifically related to how it's being used, as opposed to a hopelessly ambiguous disambiguation page, or worse, no link at all. —Preceding unsigned comment added by 24.20.9.33 (talk) 03:38, 30 May 2010 (UTC) What are specific examples of undefined symbols/disambiguation pages that prompted your request? Arcfrk (talk) 04:02, 31 May 2010 (UTC) I agree, it would be nice if the less common symbols could be linked when they're used in mathematical expressions. Unfortunately, the limitations of the current method of displaying formulas used on Wikipedia means that isn't currently possible. In the meantime, perhaps Table of mathematical symbols is some help? Qwfp (talk) 07:04, 30 May 2010 (UTC) While it's true that there are quite a few math articles that could do a better job of explaining a subject to those who aren't familiar with the notation and terminology, there are a couple of things to keep in mind. First WP is meant to be a reference, not a textbook. So while a WP article should cover the facts about a subject, it's not really meant to be used to learn the subject from scratch. Second, some subjects, especially in mathematics, are so technical by nature that it's reasonable to expect a certain level of knowledge from the reader. Not to say that there aren't some articles that have unnecessary jargon and need to be rewritten. In any case, it's not enough to simply put a general statement here and say we need to do better. If you found an article confusing or unclear then you need to indicate which one and what you didn't understand; there are are plenty of people here who are eager to make articles as understandable as possible but as far as I know none of them are mind readers.--RDBury (talk) 10:11, 30 May 2010 (UTC) +1--Kmhkmh (talk) 14:47, 30 May 2010 (UTC) Wikibooks and Wikiversity were set up for that purpose, though they are not as well supported as Wikipedia. There's quite a few other sites providing both a school and university level introduction to mathematics. Dmcq (talk) 20:06, 30 May 2010 (UTC) Have you seen Wikiversity Primary School Mathematics? Dmcq (talk) 06:50, 1 June 2010 (UTC) ## Proposed deletion of Nine-dimensional space See Wikipedia:Articles for deletion/Nine-dimensional space. Don't just say Keep or Delete; give arguments. Michael Hardy (talk) 13:35, 1 June 2010 (UTC) Is there any reason why 9-spaces are more deserving of an article than 8 or 10-spaces? If so that should probably be brought up in the article. Paul Carpenter (talk) 17:13, 1 June 2010 (UTC) ## Additional opinions desired at Talk:Hilbert space There is a question about whether or not the current article structure, of presenting Euclidean space as a detailed example of a Hilbert space before the definition as motivation, is a worthwhile structure, or whether to move it until after the definition. Comments are appreciated. Sławomir Biały (talk) 10:42, 2 June 2010 (UTC) ## External Links to Web Calculators Rubin and Ichbin disagree on the application of WP:ELNO rule #13 to external links to web calculators. The rule states "the link should be directly related to the subject of the article." Rubin contends that this rule requires that Wikipedia articles link only to web calculators where that page of the calculator's web site has functionality limited essentially to the scope of the linking Wikipedia article. Ichbin contends that the rule does not impose this requirement, and that imposing such a requirement would rule out links to many useful web calculators which implement multiple functions. The links which spawned this disagreement were to a general special functions calculator from specific special function articles and to a general measures of association calculator from the articles on specific measures of association. The wording of this dispute is by mutual agreement between the parties.Ichbin-dcw (talk) 23:14, 2 June 2010 (UTC) Seems the relevant talk page is here --JohnBlackburnewordsdeeds 23:41, 2 June 2010 (UTC) Actually there are more of them, so best to keep discussion centralised here. I would dispute the "useful" as the page linked to gives no indication what it does, how it works, with an ugly and confusing layout and very little functionality. It seems the purpose is to demonstrate an API/library, not provide a genuinely useful calculator (and even as an API demonstration it's a poor one as it's very slow, taking seconds to do even trivial calculations). So as well as WP:ELNO 13 it falls foul of number 4 or 5. And as your sole purpose here seems to be to add this site, and you have no seeming interest in improving articles in other ways, it looks like a WP:COI issue too.--JohnBlackburnewordsdeeds 23:59, 2 June 2010 (UTC) Other issues may indeed also apply to the specifc case that spawned the discussion, but could we please clear up the application of rule #13? As I pointed out in conversations with Rubin, his intrepretation would seem to disallow links to the bluebit matrix claculator from the many different matrix decomposition articles that currently link to it. I, at least, have found that calculator and those links useful.Ichbin-dcw (talk) 00:36, 3 June 2010 (UTC) I agree with JohnBlackburne that the calculator http://www.meta-numerics.net/Samples/FunctionCalculator.aspx under discussion is simply not good enough to link to. Any web calculator we link to should be at least as good as the wolfram functions site, which provides 2d and 3d plotting as well as evaluation, and has a separate page for each function. r.e.b. (talk) 00:57, 3 June 2010 (UTC) I am familiar with the Wolfram functions site; it's a great place for formulae and pretty good for graphs, but I don't know how to get it to do simple evaluations. Suppose I want to know Ai(2.13) to a few decimal places. How can I get that value from the Wolfram functions site?Ichbin-dcw (talk) 01:34, 3 June 2010 (UTC) Go to http://functions.wolfram.com/webMathematica/FunctionEvaluation.jsp?name=AiryAi r.e.b. (talk) 01:26, 3 June 2010 (UTC) Excellent! I was not aware of that! I withdraw the proposed links to the MN calculator page and propose adding links to the relevent Wolfram function evaluator pages.Ichbin-dcw (talk) 01:34, 3 June 2010 (UTC) It might be slightly better to add links to Wolfram's main page for each function, such as http://functions.wolfram.com/Bessel-TypeFunctions/AiryAi/, as these have links to the evaluation and plotting pages. r.e.b. (talk) 01:44, 3 June 2010 (UTC) I wasn't aware of those links, either. That looks like an excellent addition to the articles. — Arthur Rubin (talk) 01:50, 3 June 2010 (UTC) Baring further objections, I will add those links to the relevent special function articles. I am very happy to have a conensus resolution for those pages. It looks like the Wolfram function site does evaluations for exponential integrals (e.g. gamma and erf) and Bessel-type functions (e.g. Y and Ai), but for some reason not for orthogonal polynomials. Am I wrong about that? The MN calculator isn't great for orthogonal polynomials (it doesn't do generalized versions) but I can't find much else. Any other suggestions there? There is also the question of statistical calculators, but perhaps that is best handled in another forum.Ichbin-dcw (talk) 02:09, 3 June 2010 (UTC) For some weird reason, you can evaluate orthogonal polynomials if you look them up as hypergeometric functions, but not if you look them up as polynomials. r.e.b. (talk) 02:47, 3 June 2010 (UTC) The page http://dlmf.nist.gov/software/ might be useful for tracing down software for special function. r.e.b. (talk) 02:54, 3 June 2010 (UTC) What I hope to acomplish is to give people a way to do a quick calculation without having to download and install full software packages like those listed there. That page might be a useful external link for the List of numerical libraries article, though. Still, I am grateful to you for pointing it out, because I have been waiting for the DLMF to come online fully -- for the past ten years they have just had a couple example articles available -- and from your link I learned that they have! By the way, I have added the links under discussion to the Bessel function and Airy function articles, in case anyone wants to take a look and critique the format.Ichbin-dcw (talk) 03:32, 3 June 2010 (UTC) I'm not keen on links to calculators, I'd prefer to have some explanation or other content suitable for an encyclopaedia. As an example I would not like for instance a carpet artricle to link to something where it just calculated the amount of carpet one needed. If the carpet calculator was part of something larger that explained the workings and why though I'd think that was good. Dmcq (talk) 14:36, 3 June 2010 (UTC) ## Animated GIFs I've noticed that many animated GIFs are displayed as static GIFs in articles. For many of the math related images the first frame isn't representative and doesn't illustrate the subject. For example, in the Cardioid article the lead image is supposed to show the curve being generated as a roulette. I just get a static picture of two circles which is useless. But the animated GIF in the roulette article appears correct. I assume this change to static is keep bandwidth under control, can anyone verify this? Also, can the image parameters be adjusted (e.g. make size smaller) to ensure that the image will be animated? I'd rather have a small image that makes sense rather than a large one that doesn't. Finally, it might be a good idea to keep an eye out for images that are obviously broken; maybe these can be fixed somehow.--RDBury (talk) 02:42, 2 June 2010 (UTC) I just went over our featured images and the following are now "broken": --RDBury (talk) 03:29, 2 June 2010 (UTC) There has been a large amount of confusing discussion regarding animated gifs. See WP:VPT#GIF not animating and the links to earlier discussions that it contains. At one time I tried to summarize the conclusions: If an animation is more than 12.5M pixels total (width × height × number of frames), you get a single frame. If an animation is more than 12.5M pixels per frame, you get a thumberror. (I do not know if this summary is still accurate.) Johnuniq (talk) 03:44, 2 June 2010 (UTC) Thanks, at least now I know what the criterion is. So far I've found over a dozen math articles with broken GIFs, meaning the image no longer makes sense at all. There are a few more where the idea is still there but explanatory value is reduced. The one in the Hypotrochoid article is typical in that it's not that far over the limit and could probably be fixed by removing some of the frames.--RDBury (talk) 04:59, 2 June 2010 (UTC) In some cases the problem can be fixed by making the thumbnail image size a simple multiple of the image size (e.g. exactly 1/2). -- Radagast3 (talk) 04:08, 5 June 2010 (UTC) See Discrete_mathematics#Theoretical_computer_science for one which didn't work until I re-scaled it, although the same trick doesn't seem to work for Hypotrochoid. -- Radagast3 (talk) 04:11, 5 June 2010 (UTC) I'll go ahead and try it on the articles I found. It's somewhat counterintuitive that making the size larger would fix the problem but whatever works. Thanks for finding this.--RDBury (talk) 00:03, 6 June 2010 (UTC) It seems that setting the image to any large value will work. The graphics loader won't expand the image to larger than its original size.--RDBury (talk) 00:33, 6 June 2010 (UTC) ## Images in lists Over at Wikipedia:Articles for deletion/Gallery of curves, the suggestion has been made that List of curves could be enhanced dramatically by making it a table that includes images of the curves (and, my own suggestion, maybe some notable properties of the curve). I think that List of surfaces, an article in much poorer shape, would also benefit from a similar treatment. I figured I would post here for comment. Sławomir Biały (talk) 11:14, 5 June 2010 (UTC) This is a more complex issue than one might think at first glance. I don't think an image would be appropriate for every entry, for example we don't have images for some of the curves. The ones we do have are in a variety of different styles so aesthetics would be an issue (as it is in "Gallery of curves"). There are quite a few entries on the list so adding an image for all of them would significantly affect load times as well. But images for selected entries would probably work.--RDBury (talk) 14:51, 5 June 2010 (UTC) ## Hyperbolic coordinates FYI, Hyperbolic coordinates has been nominated for deletion. 76.66.193.224 (talk) 03:55, 6 June 2010 (UTC) Just a comment as the nominator. There are references for "Hyperbolic coordinates" as a subject but the article as it stands does not seem to come from any of them. I'd appreciated it if someone with some expertise on the subject could take a look and either add a reference that supports the material in the article or rewrite the article so it agrees with a standard reference. So far the responses have just been "keep" with no effort to show that what's in the article is supported in the literature.--RDBury (talk) 06:01, 6 June 2010 (UTC) ## Lambert's trinomial equation ? A former article on Lambert's trinomial equation was deleted last December, apparently due to copyright problems. Previous "See also" links to this article at Johann Heinrich Lambert and Lambert W function now link to Trinomial, which is not useful, as it does not define Lambert's trinomial. I can't see anything useful in Google or Google Books. Does anyone know what Lambert's trinomial is ? Or should I simply remove those "See also" links ? Gandalf61 (talk) 11:52, 7 June 2010 (UTC) I presume it is the equation mentioned on p.2 of http://www.cs.uwaterloo.ca/research/tr/1993/03/W.pdf .Charles Matthews (talk) 12:44, 7 June 2010 (UTC) Thank you. I have added that equation ($x = q + x^m$) to the trinomial article so that the "See also" links that point there now make some sort of sense. Gandalf61 (talk) 13:23, 7 June 2010 (UTC) Is this related to the Bring radical? JRSpriggs (talk) 05:08, 8 June 2010 (UTC) ## JFM template Template:JFM appears to be broken (it is not well documented, but the usual syntax for MR and a couple of variations didn't work). Does anyone know how to fix it? Unlike Zbl and MR databases, JFM is freely available. It also contains reviews of older articles (now cross-referenced from Zbl, modulo the caveat above). Arcfrk (talk) 12:07, 7 June 2010 (UTC) Should work fine now. Algebraist 12:12, 7 June 2010 (UTC) ## Knight's tour FP FYI: The knights tour animation File:Knight's tour anim 2.gif was promoted to featured picture.--RDBury (talk) 05:02, 8 June 2010 (UTC) ## Disambiguating "lattice theory" Lattice theory currently redirects to lattice (mathematics) which is a disambiguation page. A fairly large number of pages link to lattice theory, and therefore need disambiguation. Lattice (group) and lattice (order) seem to be the two most important items. Doesn't the term lattice theory usually refer to the theory of certain kinds of posets? If so then that should redirect to lattice (order)? Michael Hardy (talk) 18:02, 4 June 2010 (UTC) It used to redirect to lattice (order) until Justin W Smith (talk · contribs) changed it in April. Most of the links to it seem to intend the order-theoretic meaning, but there are exceptions: fermion doubling seems to intend lattice model (physics). Additionally there should probably be some linkage or possibly merger between the lattice (mathematics) dab page and the main lattice dab page. —David Eppstein (talk) 20:05, 4 June 2010 (UTC) I am not happy with that change at all. I think the primary meaning of "lattice theory" without further context is very clearly the theory of a certain type of posets. We could add a notice "Lattice theory redirects here for ... see ..." if the term is also used for unrelated things, or at most a disambiguation page under lattice theory. But the current situation is confusing. Hans Adler 16:51, 9 June 2010 (UTC) Hans, I think you're right. "Lattice theory" (emphasis added) would likely be in reference to lattice (order), with perhaps a few exceptions as David pointed out. I undid my change. 17:03, 9 June 2010 (UTC) ### ...and disambiguating "lattice" and naming articles..... The Lattice disambiguation page lists lattice (group) and lattice (discrete subgroup) as separate independent items. The latter is a a generalization (not a special case as the name seems to suggest). So it seems we need to look at • naming of these articles; • organizing the disambiguation page; and • links between the two lattice (...group) articles. Michael Hardy (talk) 20:58, 4 June 2010 (UTC) I know that it looks a bit confusing, yet I can't think of the titles that are better than "lattice (group)" and "lattice (discrete subgroup)" for the articles on these two topics. The former one is examplified by Γ=Zn, but some of its typical applications (e.g. in number theory or discrete geometry) do not really use the group structure on G=Rn, just the fact that Γ acts faithfully, discretely and cocompactly on a Euclidean space or a vector space. While technically the notion of a lattice Γ in a Lie group (or a topological group) G is a generalization, the theory has completely different flavor, since typically, the ambient group G is semisimple, like SL(n,R). One possibility would be to rename "lattice (group)" into "lattice (Zn)", but the cure is worse than the decease. I'd say, let it be. Arcfrk (talk) 02:44, 5 June 2010 (UTC) ## Mathematical Methods in the Physical Sciences A new editor created this article about a textbook. I added a notability tag and the editor has asked for help in establishing it. We don't seem to have many articles on textbooks and the criteria in the academics section of Wikipedia:Notability (books) seems rather vague to me, so some clarification of the notability criteria for math books and some additional input on this particular article would be appreciated.--RDBury (talk) 05:40, 8 June 2010 (UTC) If they can substantiate the article's claim that "The book ... is frequently cited in other textbooks and scientific papers.", then it is notable. Otherwise, not. JRSpriggs (talk) 17:35, 8 June 2010 (UTC) ## Six cross-ratios The new page six cross-ratios has been prodded for deletion. Tkuvho (talk) 14:56, 9 June 2010 (UTC) Please comment at Talk:Six_cross-ratios. Tkuvho (talk) 15:38, 9 June 2010 (UTC) Added a {{prod2}} --JohnBlackburnewordsdeeds 15:40, 9 June 2010 (UTC) I think it should be summarily redirected, as noted in the {{prod}}, and that redirect be nominated for deletion. But I have no real objection to the {{prod}} taking its course. — Arthur Rubin (talk) 15:45, 9 June 2010 (UTC) ## Actual infinity Several sections of this article consist entirely of quotations from other sources. Though referenced, these are not labeled as quotations so there are possible copyright issues here. In any case, a list of quotations does not constitute an encyclopedia article so much of the article needs to be rewritten. One option may be to remove the problematic material and merge the rest into Infinity.--RDBury (talk) 02:10, 11 June 2010 (UTC) The lack of quotations marks needs to be remedied, but I'm not sure a merge would be the best thing. I would think that the term "actual infinity" is deserving of its own article. Paul August 20:32, 11 June 2010 (UTC) I agree — this is a cleanup issue, not an argument against the existence of an article. From my non-lawyer perspective I doubt there's really a copyright issue, but certainly large sections consisting mainly of quotes are not good article style; it should be rewritten into prose. --Trovatore (talk) 20:44, 11 June 2010 (UTC) I added a more specific cleanup tag and changed the quoted material to block quotes. It's not really my area of expertise or interest or I'd do the rewrite myself. I'm not saying the article shouldn't exist, but I don't think it should exist in its current state.--RDBury (talk) 01:07, 12 June 2010 (UTC) ## Decimal superbase FYI Decimal superbase has been sent for deletion. 70.29.212.131 (talk) 03:58, 12 June 2010 (UTC) ## Is mentioning the Erdős number encyclopedic? I noticed that a good number of articles on mathematicians include Erdős numbers. This seems questionable trivia to me. Perhaps a more encyclopedic way of including this information is to change it to a "List of notable collaborators". Including the Erdős number in articles seems like an invitation for OR and using unreliable sources and the articles I've looked at confirm this.--RDBury (talk) 00:44, 5 June 2010 (UTC) There are reasonably reliable sources for Erdős numbers (the MathSciNet calculator, for instance). But I agree that in most cases it tends to be trivia. I think it should be mentioned when the subject of an article was a close collaborator of Erdős but otherwise omitted from our articles. (They can still be listed in List of people by Erdős number, though, if the number is at most three — beyond that the reliability of the calculations becomes more questionable.) —David Eppstein (talk) 01:34, 5 June 2010 (UTC) Having an Erdős number of 1 might be worth mentioning in a biography, but I wouldn't include higher numbers. --Tango (talk) 01:56, 5 June 2010 (UTC) Agree that the Erdős number is not worth mentioning (although I must confess that I take a certain foolish pride in knowing mine is three, it is glaringly obvious to me that it implies next to nothing about my mathematical accomplishments). Paul August 14:08, 6 June 2010 (UTC) I think "X has an Erdős number of 2" is trivia, but "At some date, X collaborated with Y, while researching this-or-that, producing some interesting result and giving X an Erdős number of 2" is just detail - and there's nothing wrong with detail. --Paul Carpenter (talk) 14:20, 13 June 2010 (UTC) ## Edit war over inclusion of image There is an edit war over the inclusion of the image File:012OrderTensorFields.svg in the articles Scalar field and Vector field. I, for one, find the image to be quite unsuitable for these articles. Why should one be worried about second order tensors in an article on scalar fields or vector fields? Not to mention the fact that, as an illustration of scalar fields per se, it is a poor illustration (arrows pointing up and down? does anyone visualize scalar fields this way?) Also, the image geometry is poor for a lead image, since it is very long and pushes much more germane images further down the page. At any rate, rather than revert the addition a second time, I thought I should post here to gauge what the consensus is. Sławomir Biały (talk) 19:57, 13 June 2010 (UTC) The same image is used in the related Vector field and Tensor field articles. The image compares the fields. If it is relevant for one, then it is relevant for all. For consistency the image should therefore be included in all, or excluded in all - and if the latter then a good reason must be given for exclusion. There is no point in "being bold" as asked for of Wikipedia editors if any time one attempts to do so and instill some consistency (and therefore professional appearance, the edit is reverted because of another editor's personal preference. JohnArmagh (talk) 20:36, 13 June 2010 (UTC) Arguing from consistency is disingenuous, since you are the very person that added it today to Scalar field and Vector field. It's Its purpose in Tensor field is, I think, to show that tensor fields generalize scalar fields and vector fields. Aside from some chimerical "consistency", what exactly is the image supposed to achieve in Scalar field and Vector field? Sławomir Biały (talk) 21:06, 13 June 2010 (UTC) The rationale was consistency, not the argument (you turned it into an argument) - and the edit and the reasoning behind it were good faith and absolutely NOT disingenuousness. So once again I require you to retract that statement. (And for your information it should be its purpose, not it's purpose - or are you going to argue that point also?) JohnArmagh (talk) 20:12, 15 June 2010 (UTC) Thanks for catching the typo! ;-) Sławomir Biały (talk) 21:01, 15 June 2010 (UTC) I agree about the image: apart from being fairly crude (though if that were the only issue I would leave it in and hope it is improved or replaced) the first of the three images does not look like a scalar field: it looks like a vector field with the vectors parallel. Even the third one looks like vectors, or like there's a frame of reference so an orientation at each point. Also the caption is far too long - it would be too long anyway (the image should be clear without needing such a long explanation) but it's far worse for a narrow and tall image, which grows by several lines because of the caption.--JohnBlackburnewordsdeeds 21:51, 13 June 2010 (UTC) The images already in the articles (File:Scalarfield.jpg and File:VectorField.svg) illustrate the concepts much better than new one. There might be a case for having it in Tensor field since there are no other images, but I doubt someone who didn't already know what a tensor field was would make much sense of it. It would be nice to have an image that conveys the abstract concept of a tensor field, but it seems a rather impossible task.--RDBury (talk) 01:24, 14 June 2010 (UTC) I agree that the image is poor. It probably ought to be removed from all three articles. Paul August 11:07, 14 June 2010 (UTC) Agreed. The images that RDBury linked to are better illustrations of scalar and vector fields. Gandalf61 (talk) 11:48, 14 June 2010 (UTC) Which is reasonable (unlike the somewhat authoritarian approach of Sławomir Biały). It is not a very good image - but it is the one being used. If it is unsuitable then it should be removed from all the articles. JohnArmagh (talk) 20:15, 15 June 2010 (UTC) Pot, please allow me to introduce kettle. Sławomir Biały (talk) 21:01, 15 June 2010 (UTC) ## WAREL revisited Motomuku (talk · contribs) seems quite similar; adding minor unsourced incorrect changes to Perfect number, although WAREL was mostly dealing with odd perfect numbers, and Motomuku with even perfect numbers. He apparently also is emphasizing the (disputed) importance of Japanese people. — Arthur Rubin (talk) 08:32, 15 June 2010 (UTC) See also Wikipedia:Requests for comment/WAREL. Sławomir Biały (talk) 09:57, 15 June 2010 (UTC) ## Reliable sources issue at help desk For anyone who does not monitor the help desk, an issue has come up on the Collatz conjecture that I thought deserved a cross-post here. See Wikipedia:Reference desk/Mathematics#Could someone please look at this supposed solution to Collatz conjecture.--RDBury (talk) 12:44, 16 June 2010 (UTC) While we're at it (same editor), Vantieghems theorem may possibly only need an apostrophe, but I'd prefer a solid reference and a notability check. Charles Matthews (talk) 17:35, 16 June 2010 (UTC) ## The Problem with Wikipedia Maths and a solution... perhaps Hi everyone, I don't usually edit so apologies if I'm breaking any conventions here. I use parts of the Mathematics project fairly regularly and as useful as I find it, there is a major problem; one which I am not the only one to experience. I think it is best to show an example of a potential route though Wikipedias maths sections, using the particular strategy of clicking on the link after "is a": • 5 • 5 (number) • number • mathematical object • abstract object • object Great! I've learnt that (the number) 5 is something (probably). OK, obviously if I click on the link after "is a" I get a more general set of things. Indeed, it is the behaviour that one would hope for. However, this induces a problem in the maths articles (more so than others). It is used as a crutch to avoid actually describing what things are, which is a problem for the uninitiated. Instead of getting an understanding of something, I find myself falling into a spiral of abstraction and being just as confused as I was to start with. Admittedly, the problem is worst when I do not know when to stop, as I am unfamiliar with the topic and is unsure about what is and isn't important (my guess is that being unfamiliar with a topic is the main reason for someone to visit the page). Other people have mentioned this to me, "yeah, I never use wikipedia for maths because they make it too hard to understand" My suggestion is to make one of those sidebar things for each section of maths: show the reader what other things are important to their understanding of a particular thing, not just an abstraction. It should have 3 sections, one for concepts which a specific examples of that thing, one for generalisation(s) and one for things that are related on the same `conceptual level', including (highlighted) those immediate things that must be understood. For example Vector Space: Important concepts: • Vector • Vector Multiplication • Scalar Multiplication • Coordinates • Linearity • etc Generalisations: • Complex Vector Space • Things that I can't remember the names of • Things that I havn't heard of • etc Examples: • Normed Vector Space • Real Number Line • Hilbert Space • etc Anyway, Just a thought, perhaps it can be near-automatically generated from the links (I have a fairly good idea how to do this). Any thoughts/blunt criticism would be welcome Lucaswilkins (talk) 23:47, 17 June 2010 (UTC) Sounds like you would like for things to be classified ontologically. Gee, what a great idea.Greg Bard 00:01, 18 June 2010 (UTC) Now some of this is actually a problem with mathematics itself, you know. Where sidebars have been tried, mostly they have been unpopular: some articles have footers with related topics. But what we are really required to do is to treat mathematics as a collection of facts, and to report on it that way. In many parts of mathematics there is a degree of abstraction. I can sympathise with anyone who finds that learning mathematics from Wikipedia is tough, but it is a reference work, not a textbook. Other encyclopedic works on mathematics have a similar style. Charles Matthews (talk) 07:22, 18 June 2010 (UTC) Sidebars (normally placed on the right at the top of an article) are best suited to short lists of up to about 5 or 6 items. For longer lists, navboxes (placed at the end of an article) are better because they are less intrusive and are collapsible. We already have a bunch of these for different mathematical topic areas - see Template:Mathematics-footer, Template:Algebra-footer and Template:Topology-footer for examples, and Category:Mathematics templates for a more complete list. What you are proposing is not a fundamentally bad idea, but it would be very difficult to create and maintain a topic-specific template for every mathematics article, and there is not much benefit, as it is basically duplicating a set of links that should already be in the article text or its See Also section, and duplicating a taxonomy that is implemented through Categories. Gandalf61 (talk) 10:58, 18 June 2010 (UTC) <cackle>Oh dear he's found us out. Bubble bubble toil and trouble, I stir the pot that is Wikipedia and throw in new references, and watch as the users spiral into the vortex of links to wake up hours later with part of their life sucked out of them and not knowing what they were looking up originally. Hee hee hee Dmcq (talk) 11:22, 18 June 2010 (UTC)</cackle> We hear these sorts of complaints on a pretty regular basis here. Usually they're not as articulate as you, and usually they don't come with suggestions. Pretty uniformly, the math community here rejects those complaints. Unlike you, most of the complainers seem to think that the problem lies with us and our writing: If only we wrote better, they'd pass math! I'm starting to wonder, however, if there isn't some truth to those complaints. In the "real world" of math papers and math publications, there are good and bad expositors. Serre and Milnor, for instance, are noted for being excellent writers. The AMS has a prize for good exposition which few people are deserving of. Once in a while you will hear someone complain about the quality of a paper (though since we don't want to offend our colleagues, this is usually quite discreet). Which suggests to me the question: Is most of the math writing on WP good or bad? I don't think it's a wholly fair question, because we have some unusual constraints. Foremost among these is time (it's not our job to write here). Also there is expertise (while there are many experts here, there are also many non-experts). But even granted those constraints, sometimes we produce good work and sometimes bad. I think derivative is very good right up until the section on the total derivative. But the total derivative section, especially its first paragraph, isn't. It is—in my opinion—bad. Or at least not good. Now, I'm not claiming that most math on WP is bad. I think the people who contribute here do so out of a love of exposition, and they are skilled and dedicated to it as few mathematicians are. But there are always failed sentences and paragraphs. I wonder if we aren't humble enough in the face of our weaknesses. Maybe one way to improve WP's math articles is to admit that sometimes, our choice of words was a mistake. Ozob (talk) 11:53, 18 June 2010 (UTC) Writing accessible mathematics texts is hard. Writing them in an Encyclopedic style that satisfies WP:V, WP:NPOV and WP:OR is even harder. My experience is that getting technical math and physics articles to a decent accessible level, while satisfying all the other constraint can easily take a couple of editors a few months. The result is clear, there are not that many very well written math articles (although there are definitely some). With time their number will (slowly) rise. In the time being it is much easier to write math articles that stick closer to standard textbook expositions (which are typically written in a dialect of English unintelligible to the uninitiated). The volume of such article is much greater, and while not useful to a lot of user, they are still useful too quite a few people that do get the peculiar dialect of English. (Wikipedia is the first place a lot of physics and math grad students look when confronted by an unknown concept.) TimothyRias (talk) 12:41, 18 June 2010 (UTC) Yes, I agree. The issue of WP:V is particularly relevant if we are trying to write a popularization of a graduate-level topic. However, for more elementary articles, the main obstruction is labor. A separate issue is that there is not universal agreement on what an article here should be. For survey articles, I like the style of Computability theory, which I contributed a to, but others find it too advanced. — Carl (CBM · talk) 14:19, 18 June 2010 (UTC) ## Pending changes The Randomness article has been added to the trial of the new Pending changes system. The best explanation I have seen of this system is in this image. Any user in good standing is eligible to be added to the "reviewer" group, but it is not automatic. You only need to ask an admin to add you to the group. Apart from that, if you would like access to the "rollback" feature to quickly undo vandalism, is can also be granted by admins on request. — Carl (CBM · talk) 14:12, 18 June 2010 (UTC) ## Inner product display template Please try out the following template "Inprod" for displaying inner products and comment on its appearance. It's meant to be used for inline text. Feel free to experiment with different inline text situations. Thanks. {{Inprod|A|B}} results in $\scriptstyle \langle$ A , B $\scriptstyle \rangle$ --Bob K31416 (talk) 23:27, 8 June 2010 (UTC) Comments: • I think it ({{inprod}}) should be renamed {{inner product}} , the current name "inprod" may elicit confusion with wikispeak ("prod" is a deletion process on Wikipedia). Though isn't just displaying a paired term right now? (and thus could be used for a pair of coordinates) 70.29.212.131 (talk) 04:34, 9 June 2010 (UTC) Thanks for your comments. Unortunately, I didn't understand your remark, "Though isn't just displaying a paired term right now?" I'd appreciate it if you explained it and perhaps gave an example of what you meant. I'm interested in how the above example displays on your computer, since displays can vary from computer to computer. For example, if instead of using the above template, one uses &lang;A,B&rang;, the angle brackets tend to be displayed as boxes on Mac computers. Regards, --Bob K31416 (talk) 15:14, 9 June 2010 (UTC) • It's still a bad template. Instead of using & thinsp; in text, you should use the technique {{val}} uses at {{val/delimitnum/fraction}}, namely < span style="margin-left:0.25em" > ... < /span >. I don't think it looks that good, even so, but that doesn't look good. — Arthur Rubin (talk) 04:54, 9 June 2010 (UTC) Thanks for your comments. What is the advantage of using < span style="margin-left:0.25em" > ... < /span > instead of &thinsp;? And would it result in a fractional space before and after each vector, which was the purpose of &thinsp;? Perhaps you could use span style to create a new template that is an improvement? I would appreciate that. Re "I don't think it looks that good" - Could you give an example, with or without a template, of something that looks better, for the above example using A and B? Regards, --Bob K31416 (talk) 15:14, 9 June 2010 (UTC) The & thinsp; doesn't display on my current configuration, while & lang; and & rang; do. As for < span style >, see the discussion of {{val}}, probably at Template talk:val, but possibly in the WT:MOSNUM archives. It moves creates spaces of 1/4 mdash, which provides the visual effect of a thinsp, but can be pasted. Are you trying to simulate < math> < A,B > < /math>? — Arthur Rubin (talk) 16:00, 9 June 2010 (UTC) I'm not sure what you meant by "trying to simulate < math> < A,B > < /math>" but I'll try to answer as best as I can. There is a problem with displaying angle brackets for inner products in inline text in Wikipedia. Using [itex] with or without \scriptstyle doesn't look very good for inline text. The HTML codes &lang; and &rang; are good on most computers, and I happily used them myself, until I found out that they tended to display as boxes on Mac computers and on some Windows computers too, and also appear as question marks in some cases. So I tried to find a way to display angle brackets that were as good or nearly as good as those HTML codes, and which didn't have the complete failure of boxes and question marks that occurs with those HTML codes on most Macs and some other computers. I have no pride of ownership regarding this task and I would be tickled if someone could come up with a template that would do the job better than what I have, without the problem with &thinsp; that you mentioned that you had on your computer. Regards, --Bob K31416 (talk) 17:34, 9 June 2010 (UTC) • It looks very bad to me: mis-sized and misaligned with the brackets jagged: $\scriptstyle \langle$a , b$\scriptstyle \rangle$. It goes against the recommendations in the MOS for using LaTeX images inline, and that was written with single images in mind, i.e. with whole formulae represented as images. Having multiple images in a single formula is much worse for page load times and alignment. Images also don't play nice with other mathematical templates, like $\scriptstyle \langle$a , b$\scriptstyle \rangle$2 and $\scriptstyle \langle$a , b$\scriptstyle \rangle$ + $\scriptstyle \langle$c , d$\scriptstyle \rangle$.--JohnBlackburnewordsdeeds 15:31, 9 June 2010 (UTC) Thanks for your comments. Could you give an inline text example that isn't "mis-sized and misaligned with the brackets jagged" so that I can see more clearly what you mean? Re your examples of use with the templates {{frac}} and {{math}}, I didn't see the problems on my computer, although I don't think it was appropriate to use {{frac}} and simply using / 2 would have been preferable for me. What were the problems in your examples that used {{frac}} and {{math}} on your computer? And could you give examples where you didn't have problems on your computer displaying inline text with inner products and {{frac}} and {{math}}? Regards, --Bob K31416 (talk) 16:22, 9 June 2010 (UTC) This a, b works much better on my machine, e.g. a, b2 or a, b2 + ⟨c, d2. The brackets scale and are smoothed like the other text, the baselines are aligned, and no images so it loads and renders the paragraph instantly, not slowly and multiple times as images are loaded. I notice now also your template has a lot of extra spacing that looks out of place. I don't see anything in the manual of style on this but standard mathematical typesetting would only put spaces after the comma, e.g. $\lang \mathbf{a},\mathbf{b} \rang$ --JohnBlackburnewordsdeeds 17:09, 9 June 2010 (UTC) I would use your suggestions for the left angle bracket &#x27e8; [39] and right angle bracket &#x27e9; [40], but unfortunately they display on various systems as question marks or boxes. I'm open to any suggestions for a better way of displaying angle brackets in the template. --Bob K31416 (talk) 11:00, 10 June 2010 (UTC) • Comment. I am against any proposal that mixes PNG images with html. One issue is that these do not scale properly: e.g., (−1)$\scriptstyle \langle$a , b$\scriptstyle \rangle$ looks like all symbols are at nearly the same height, versus (−1)a,b or $(-1)^{\langle a,b\rangle}$. Also, the current template wraps around newlines, but that might be fixable. Sławomir Biały (talk) 18:37, 9 June 2010 (UTC) I would use your suggestions for the left angle bracket &lang; [41] and right angle bracket &rang; [42], but unfortunately they display on most Mac computers and some Windows computers as boxes. I'm open to any suggestions for a better way of displaying angle brackets in the template. --Bob K31416 (talk) 11:15, 10 June 2010 (UTC) That seems unlikely: I can imagine there are old versions of Windows or IE that have problems displaying them, but modern versions of Windows and all versions of OS X should be fine as "⟨" and "⟩" are just Unicode characters and unexotic ones at that. Wikipedia is Unicode based, and if you have problems viewing common Unicode characters the thing to do is work out why and fix it on your machine, not make viewing and editing worse for everyone else.--JohnBlackburnewordsdeeds 12:02, 10 June 2010 (UTC) John, Were you referring to &#x27e8; and &#x27e9;, or &lang; and &rang; ? If the former, perhaps you should move your comment to the appropriate thread above with your previous message. --Bob K31416 (talk) 12:40, 10 June 2010 (UTC) In any case, John was referring to either option 1 (&lang; and &rang;) or option 8 (&#x27e8; and &#x27e9;) in the table below. (I think he meant option 8, which he recently added to the table.)--Bob K31416 (talk) 01:35, 11 June 2010 (UTC) ### Table There was recent thread about this at Talk:Pythagorean theorem#Angle brackets and an overview of some options at Talk:Pythagorean theorem#Putting it together. There was little attention, so perhaps it would be a good idea to take over the table and have some more input here. DVdm (talk) 11:16, 10 June 2010 (UTC) Option1 Option2 Option3 Option4 Option5 Option6 Option7 Option8 User (~~~) HTML HTML Math+HTML+ Math+HTML HTML Math Math Math+HTML+ Math+HTML HTML (math symbols) inline 〈v,v1/2 test inline 〈v,v1/2 test inline $\langle$v,v$\rangle$1/2 test inline <v,v>1/2 test inline $\langle \mathbf{v},\mathbf{v} \rangle ^{1/2}$ test inline $\scriptstyle \langle \mathbf{v},\mathbf{v} \rangle ^{1/2}$ test inline $\scriptstyle \langle$v,v$\scriptstyle \rangle$1/2 test inline ⟨v, v1/2 test unreadable (boxes) very ugly ugly OK very ugly OK OK unreadable (boxes) DVdm (talk) unreadable (boxes) poor fair fair poor fair good unreadable (boxes) Bob K31416 Mac good poor fair fair poor fair good unreadable (boxes) Bob K31416 Windows poor (can't read) poor (extra space) fair (looks fine, but Math/HTML mix) poor (wrong use of character) fair (too big for inline) good fair (looks fine, but Math/HTML mix) Blue Moonlet Mac too wide too wide ugly ugly ugly ugly ugly OK JohnBlackburne OS X 10.6 good fair (too wide) fair (OK, but doesn't scale) poor (wrong character) fair (OK, but too large, inline) good poor (a little worse than 3, and doesn't scale good (renders a little heavier than #1 in some resolutions) Arthur Rubin Windows XP, Opera good fair (extra space) fair (mixes Latex and html: poor in more complex formulas) poor (wrong character) fair (too large inline) good fair (looks worse than 3 at normal size, scales better) good Sławomir Biały (talk) 11:21, 11 June 2010 (UTC) Debian Etch, Iceweasel unreadable unreadable OK too wide too big OK best unreadable JRSpriggs poor (too wide) poor (too wide) poor (brackets too big) fair (not true angle brackets but understandable and portable) fair (too big but whole formula has a consistent size) ok fair (appearance not bad but doesn't scale) good David Eppstein (talk), OS-X, Chrome and Safari produced the identical appearance. good, but very faint / boxes good, but coarse pixels ugly (grotesquely high brackets) fair very ugly very ugly fair best / boxes Hans Adler, Firefox / Internet Explorer, on Windows with many fonts installed This might help compare the various options of the above table: 1. inline 〈v,v1/2 test 2. inline 〈v,v1/2 test 3. inline $\langle$v,v$\rangle$1/2 test 4. inline <v,v>1/2 test 5. inline $\langle \mathbf{v},\mathbf{v} \rangle ^{1/2}$ test 6. inline $\scriptstyle \langle \mathbf{v},\mathbf{v} \rangle ^{1/2}$ test 7. inline $\scriptstyle \langle$v,v$\scriptstyle \rangle$1/2 test 8. inline ⟨v, v1/2 test --Bob K31416 (talk) 02:43, 11 June 2010 (UTC) I've added my variant to the above table as it's clear it's different to what was there already. The wrong brackets may have come from the Edittools, which are now fixed, so that may have accounted for why they were not displaying properly for some people.--JohnBlackburnewordsdeeds 12:44, 10 June 2010 (UTC) FYI, the older version (CJK brackets) that was referred to in your link "fixed" is Option 2 in the table above. Regards, --Bob K31416 (talk) 02:13, 11 June 2010 (UTC) I know - it's while looking at it and the ones I used that I realised why it was too wide. The other brackets in column 1 are Unicode 2329 and 232A from the "Miscellaneous Techical" block, i.e. they are computer symbols which look similar but again are too wide. Just found something of relevance here, which explains it: The left and right angle brackets at U+2329 and U+232A have long been canonically equivalent with the CJK punctuation characters “〈” and “〉” (U+3008 and U+3009) . Canonical equivalence implies that the use of the latter code points is preferred and can be substituted at any time. As a consequence, not only 3008 and 3009 but also the characters 2329 and 232A are ‘wide’ characters. See Unicode Standard Annex #11, East Asian Width [EAW]. Unicode 3.2 added two new mathematical angle bracket characters ⟨ ⟩ (U+27E8 and U+27E9) that are unequivocally intended for mathematical use and should be used instead of U+2329 and U+232A. So of the three Unicode char pairs the ones we should use are the angle brackets (Unicode 3.2 was released in 2002).--JohnBlackburnewordsdeeds 11:57, 11 June 2010 (UTC) The responses in the table to the option 8 that you entered, suggest that for computers where it is readable, it works better than the CJK characters of option 2. But unfortunately the other responses suggest that there may be a significantly increased number of computers where it is unreadable. --Bob K31416 (talk) 02:40, 12 June 2010 (UTC) I'm not sure how much worth the table has in this form, since people may disagree on what looks ugly, poor, fair, ok - by looking at the same version, that is. If you have different authors testing different versions (on different Browsers or OS), we have no idea whether it looks really bad (=all agree it looks bad) or whether it just looks bad from the perspective of that particular tester.--Kmhkmh (talk) 03:04, 11 June 2010 (UTC) I suspect that the vast majority of readers would accept all of them, except the ones that are unreadable. --Bob K31416 (talk) 03:46, 11 June 2010 (UTC) Option 6 seems to be knocking harder and harder on the door by the minute... —Preceding unsigned comment added by DVdm (talkcontribs) 12:09, 11 June 2010 (UTC) There might be some objection that using \scriptstyle inline might have unintended consequences. I have not been present for all of the debates about this, but there seems to have been some heated discussion on this very issue at WT:MOSMATH. Sławomir Biały (talk) 12:36, 11 June 2010 (UTC) Using \scriptstyle outside (sub|super)scripts is a typographic disaster, because TeX omits all the spaces around binary operation and relation symbols in scriptstyle: cf. $\scriptstyle x+y=z$ to $x+y=z\,$. It would be an uphill battle to persuade users of the template to insert the missing spaces (and only them) manually, as in $\scriptstyle x\,+\,y$.—Emil J. 14:11, 11 June 2010 (UTC) I had problems trying to implement options 5 or 6 in a template. I experimented in the template sandbox X9.[43] For example, users wouldn't be able to enter vectors in the inner product because parameters didn't work when they were between [itex] and. There were other problems too, such as how to implement the options of bold font for the vectors and exponents for the inner product, in a user friendly way.
Option 7 didn't have those problems when making a template ( {{Inprod}} ) and option 3 wouldn't either, since they used [itex] only for each angle bracket individually. Also, the other 4 options wouldn't have those problems when making a template. --Bob K31416 (talk) 16:37, 11 June 2010 (UTC)
Option 7 looks the best to me. 3 and 6 are OK. 4 is too wide. 5 is too big. 1, 2, and 8 are unreadable. JRSpriggs (talk) 18:19, 11 June 2010 (UTC)

(The following is based on the current state of the table where Hans Adler's entry was the last.)

Summary of short parts of comments for the options 1–8:

2. very ugly, poor, poor, poor, too wide, fair, fair, unreadable, poor, good, good
3. ugly, fair, fair, fair, ugly, fair, fair, OK, poor, ugly, ugly
4. OK, fair, fair, poor, ugly, poor, poor, too wide, fair, fair, fair
5. very ugly, poor, poor, fair, ugly, fair, fair, too big, fair, very ugly, very ugly
6. OK, fair, fair, good, ugly, good, good, OK, OK, very ugly, very ugly
7. OK, good, good, fair, ugly, poor, fair, best, fair, fair, fair

In my opinion, these comments suggest the following order of best (option 6) to worst (option 8):

6. OK, fair, fair, good, ugly, good, good, OK, OK, very ugly, very ugly
7. OK, good, good, fair, ugly, poor, fair, best, fair, fair, fair
3. ugly, fair, fair, fair, ugly, fair, fair, OK, poor, ugly, ugly
4. OK, fair, fair, poor, ugly, poor, poor, too wide, fair, fair, fair
5. very ugly, poor, poor, fair, ugly, fair, fair, too big, fair, very ugly, very ugly
2. very ugly, poor, poor, poor, too wide, fair, fair, unreadable, poor, good, good

Since options 5 and 6 are not amenable to being used in a template (see a previous message), here's the above option order without 5 and 6, i.e. the ordered sequence of options that can be used in a template from best (option7) to worst (option 8):

7, 3, 4, 2, 1, 8

--Bob K31416 (talk) 18:44, 14 June 2010 (UTC)

Please note that option 7 was the one that was used in the template {{Inprod}}, which was the subject that started this discussion Inner product display template. --Bob K31416 (talk) 10:35, 19 June 2010 (UTC)

Note: Not all !voters expressed an opinion about the acceptability of mixing HTML with LaTeX. Most merely commented about the looks. So, based on the looks we have indeed 7, 3, 4, 2, 1, 8, whereas when we exclude 7 and 3, we have:

4, 2, 1, 8.

- DVdm (talk) 12:53, 19 June 2010 (UTC)

For what it's worth, I started this section Inner product display template as an attempt to sample how {{Inprod}} appeared on users' computer systems, for the purpose of template development. I thank all those who participated, and if anyone who hasn't responded would like to share their information on that, it's still welcome. Regards, --Bob K31416 (talk) 15:15, 19 June 2010 (UTC)
Regarding the issue of how to display the notation for inner products in inline text, I don't see that any of the options would please a consensus of editors. Perhaps some day the Wikipedia software developers will be able to have mathematical expressions such as inner products, displayed properly in inline text. Or maybe some day, fonts for proper angle brackets, like option 8, will be installed and work properly on nearly all computers, but apparently this is very slow in coming. --Bob K31416 (talk) 15:37, 19 June 2010 (UTC)

## Template:Logic

Greg is vandalizing the template, in the guise of "following redirects"; even if "following redirects" were appropriate in templates, he's also removing redirects such as Model (logic) from the model theory section. I don't know how many other templates he's vandalizing. — Arthur Rubin (talk) 02:32, 19 June 2010 (UTC)

You will find that my edits are innocent and appropriate. This is Arthur behaving very immaturely, in my opinion.Greg Bard 02:33, 19 June 2010 (UTC)
At this point I have to request that the group look in on Arthur. It is possible that he just doesn't see what he is doing. I am trying to avoid redirects and Arthur is reinserting them like a mad man. Do you guys love Arthur at all? Look in on him for his own sake at this point. Greg Bard 02:40, 19 June 2010 (UTC)
If you remove entries which are redirects, it's a significant change; as most of your significant changes are inappropriate in any article referenced in a mathematics article, I think it's appropriate. to revert you on sight if any of the edit is clearly wrong. If you were to (1) follow each redirect, deleting none; (2) remove duplicates and realphabetize; and (3) THEN make any substantive edits which may seem appropriate, then I would consider only reverting step (3). Steps (1), although unneccesary, is not vandalism. Step (2) is minor. Step (3) is one you are likely to do wrong, as you do not understand classical logic. — Arthur Rubin (talk) 02:49, 19 June 2010 (UTC)

So basically you made all this drama because you want a link to "model." What a baby. I have no problem with that --baby.Greg Bard 03:01, 19 June 2010 (UTC)

No, I noticed the link to "model" was gone. There were also at least 7 links in the sections loosely related to mathematical logic which were deleted, and I don't know how many others may be appropriate. As you've shown you do not understand mathematical logic, please do not make any changes other than following redirects in those sections. — Arthur Rubin (talk) 03:06, 19 June 2010 (UTC)
Arthur you have shown what type of person you are also. I have an excellent understanding of logic, by any standard. This is just you behaving like a prima donna, and being impossibly demanding. You are wasting everyone's time with your tactics. I am perfectly open to whatever links you want. So what exactly is your problem?! A problem that is so pressing you feel a need to insult. You are an uncivil person Arthur, plain and simple. Greg Bard 03:12, 19 June 2010 (UTC)
I don't feel a need to insult. As you don't respond to reason, I thought I'd try accurate descriptions for the benefit of those with the ability to block you, if they find it appropriate. I, of course, may not block you. Your lack of understanding is quite apparent from your edits to model (logic), in regard the deleted Category:Strings of symbols, and a number of other edits. — Arthur Rubin (talk) 03:20, 19 June 2010 (UTC)
The statement "you don't respond to reason" goes against WP:AGF Arthur. At some point you need to learn how to respectfully disagree.Greg Bard 03:44, 19 June 2010 (UTC)
WP:AGF is not a suicide pact. — Arthur Rubin (talk) 03:48, 19 June 2010 (UTC)
Prove me wrong; discuss your edits at Template talk:Logic#"Follow redirects". — Arthur Rubin (talk) 03:49, 19 June 2010 (UTC)

Actually, Arthur, I think you should step back from this: there are others in the project quite competent to assess the template, and with less baggage. A string of personal attacks is simply not likely to resolve such a dispute. Charles Matthews (talk) 10:14, 19 June 2010 (UTC)

Thank you for your decent, and measured response Charles M. I want to let you and others in the project to know that I trust them with this task and I certainly invite any correspondence or questions about this incident.Greg Bard 22:45, 19 June 2010 (UTC)

# Jul 2010

## Is it appropriate for an article to mandate a unicode character?

There is a discussion at Talk:Convolution about whether it is appropriate to mention in the "Definition" section of the Convolution article the designation of the unicode glyph for the asterisk. To me, this seems to be utterly irrelevant in the article. Anyway, I've been accused of edit-warring there (on what seem to be quite spurious grounds). I'd like to ask for other opinions. Sławomir Biały (talk) 19:45, 22 June 2010 (UTC)

I do not believe an ordinary article on mathematics should talk about the unicode points of the characters in mathematical notation. There are a few articles specifically about symbols, and those are an obvious exception. But the article on convolution is not an exception. — Carl (CBM · talk) 00:58, 23 June 2010 (UTC)

## The Diophantus-Brahmagupta-Fibonacci-Lagrange identity

Some terminological confusion that may be beyond Wikipedia's scope to sort out, but let's see. (Note: Diophantus lived in the 3rd century, Brahmagupta in the 7th, Fibonacci in the 12th/13th, and Lagrange in the 18th.) We have an article at Brahmagupta–Fibonacci identity, which gives the identity

$\left(a^2 + b^2\right)\left(c^2 + d^2\right) {}= \left(ac-bd\right)^2 + \left(ad+bc\right)^2$

(that shows, among other things, that the set of sums-of-squares is closed under multiplication). Now it so happens that although "Fibonacci's identity" elsewhere does seem to refer to this identity, Brahmagupta knew and used something more general:

$\left(a^2 - Nb^2\right)\left(c^2 - Nd^2\right) {}= \left(ac+Nbd\right)^2 - N\left(ad+bc\right)^2$

The previous identity is the special case N=-1. It seems a "waste" to use the name Brahmagupta's identity for the special case. (And in fact the special case may not even be in his work; I haven't checked.) Moreover, the special case — sum of squares — was also known to Diophantus! So why is Fibonacci's name associated with it? (It is hard to suggest that someone knew one of these identities but not the proof; since the proof is trivial.) Should we rename some articles here, or is it the kind of thing we cannot do? Shreevatsa (talk) 00:29, 26 June 2010 (UTC)

I think we have to go by generally accepted naming, as indicated by the usual reliable sources. -- Radagast3 (talk) 03:09, 26 June 2010 (UTC)
I know; hence the first and last lines of my comment. But the question here is precisely to determine what "generally accepted naming" is. For sources which refer to the second identity above as Brahmagupta's identity, see (apart from the book already linked): MathWorld, here, here, here,