Wikipedia talk:WikiProject Mathematics/Archive/2014/Dec

A new redundant category

Greenrd (talk · contribs) has created Category:Foundations of mathematics which is redundant with Category:Mathematical logic. JRSpriggs (talk) 08:47, 1 December 2014 (UTC)

According to Topics in mathematics in Portal:Mathematics, the latter is a subset (subcategory) of the former. Just noting, I have no opinion. YohanN7 (talk) 09:21, 1 December 2014 (UTC)

Two articles in Category:Foundations of mathematics are already in Category:Systems of set theory which is in Category:Set theory which is in Category:Mathematical logic. And Category:Foundations of mathematics is in Category:Fields of mathematics which already contained Category:Mathematical logic. This is as one would expect since "Mathematical logic" and "Foundations of mathematics" are synonyms. JRSpriggs (talk) 09:37, 1 December 2014 (UTC)

I disagree that "Foundations of mathematics" and "Mathematical logic" are synonyms: For taking a simple example, Automated theorem proving and category:Automated theorem proving‎ belong naturally to "Mathematical logic" and are far to belong to the foundations of mathematics. On the other hand, the foundations of mathematics clearly involve philosophical and epistemological questions which do not belong to mathematical logic. The debates between constructive analysis and non-standard analysis vs. classical analysis are examples of questions of foundations of mathematics that do not belong to mathematical logic, as involving the same logical foundation. D.Lazard (talk) 10:56, 1 December 2014 (UTC)

Can you help with an excessive quotation issue?

An IP brought up concerns at the copyright problems board about the extensive quotation at Josip Plemelj - from the third paragraph under "A geometrical construction from his schooldays" to the end is a quote. Investigation confirms that this material is likely under copyright, which means that the IP is right that the quotation doesn't comply with copyright policies. WP:NFC forbids extensive quotation. I would really prefer to ask somebody to help turn that into a proper paraphrase than to blank the section - I think it's quite unlikely that I could paraphrase it myself, since the material is so far from my realm. Would any of you be able to help out with this? If not, I can of course apply the usual {{copyvio}} template to the section in hopes that somebody else will. But with a case like this one, I really hate to do that. :) If there's no takers, it'll probably be blanked in a day or so and removed or truncated in about a week. --Moonriddengirl ^(talk) 11:58, 20 November 2014 (UTC)

This strike be a bit odd, since while still possibly being a copyvio it is certainly no verbatim quote as the original source is in Slovenian and not in English. So the question here is whether the "translation" is too literal/close to the original. One option of course would be imply to rewrite the mathematical content as it is, but it certainly would preferable if we get Slovenian speaker who can verify the IP claim and help rewriting the paragraph witn actually being able to read the source.

Another issue might be that such an extensive coverage of a childhood episode might not all that appropriate for an encyclopedic article.--Kmhkmh (talk) 13:50, 20 November 2014 (UTC)

The quote in question is very long and includes many details of conversations and school schedules. It is not encyclopedic. Perhaps the optimal resolution is to summarize this episode in Plemelj's life in a couple of sentences. Mgnbar (talk) 13:47, 20 November 2014 (UTC)

Shortening the section seems appropriate to me. Do you have access to the source and can you read it by any chance?--Kmhkmh (talk) 13:51, 20 November 2014 (UTC)

The quote was probably added by User:XJaM, who might be able to help. r.e.b. (talk) 18:23, 20 November 2014 (UTC)

I'm so grateful for all of your responses. :) Projects do not always pitch in like this. I have now asked for User:XJaM's help. Whether or not he added it, he is familiar with the subject area (having edited the article) and might be able to help. :) Summarizing it would suit fine if the verifiability of the content is not suspect. --Moonriddengirl ^(talk) 12:20, 21 November 2014 (UTC)

In the absence of any other action on this, I've now gone ahead and removed the quote. But I see no reason why the constructions and accompanying diagrams should not be restored to the page if anyone has the skills and inclination to do that. Thanks to all who responded above. Justlettersandnumbers (talk) 23:48, 1 December 2014 (UTC)

"Notability" of Stirling polynomials

The "notability" of the topic of the new article titled Stirling polynomials is being questioned. Would perhaps a few more references settle that? Michael Hardy (talk) 23:25, 1 December 2014 (UTC)

Like most of that user's edits, none of the identities appearing in the article appear in the cited source. Sławomir Biały (talk) 23:43, 1 December 2014 (UTC)

To clarify my tagging: the article contains not even the most basic statement of why one should find these objects interesting, and this is why I tagged it. (I also think the "context" tag should be put back, but evidently User:Michael Hardy thinks the two sentence lead I wrote is sufficient on this front :).) --JBL (talk) 00:11, 2 December 2014 (UTC)

Draft:Gaussian process latent variable models

Hello, mathematics experts! Should Draft:Gaussian process latent variable models be published? --Cerebellum (talk) 07:25, 3 December 2014 (UTC)

This is not in my field. However, it strikes me as someone taking a well-known idea, slapping a new name on it and then trying to claim credit for it. JRSpriggs (talk) 16:31, 3 December 2014 (UTC)

User:Brirush Sectionifying

Over the last couple of weeks, since at least 22 Nov, User:Brirush has been "Sectionifying" lots of articles, splitting the leads up into lots of sections leaving behind a diminished lead which often says practically nothing e.g. arithmetic topology, arithmetic combinatorics, topological combinatorics. I believe it might be a good idea to just wholesale revert all the articles that have been sectionified rather than trying to check each one individualy to see if any of the sectioning was justified. 2.97.23.254 (talk) 16:27, 1 December 2014 (UTC)

I have no problem with you reverting the edits, but make sure you don't revert ones like Nash-Moser theorem, cofunction and computable analysis where content was added, unless you dislike the content. The size of the edit should be a clue. I do not plan on doing the reverts myself, as I obviously find my edits useful, but I won't keep you from reverting them.Brirush (talk) 17:00, 1 December 2014 (UTC)

Other useful ones to avoid deleting: Adding reference to R (complexity), adding image to conformal equivalence, adding "see also" items to many articles, adding an image to convex body, expanding dimension theory significantly, etc. I hope you exercise some restraint in your reverts.Brirush (talk) 17:26, 1 December 2014 (UTC)

Just to give another perspective, I looked at some of Brirush's edits and they all look improvement to me. (The amount is such that as if someone is paying him to do it.) Ledes don't need to be long and in fact many Wikipedia articles can use "sectionifying". People, both creators of the pages and others, (by which I mean editors such as myself) tend to add materials and changes in the organizational structure tend to lag behind. He is just correcting this. -- Taku (talk) 18:41, 1 December 2014 (UTC)

Yes, I agree with Taku. This is part of the natural process of turning stubs into something better than stubs; it gives them more structure, making it easier to see where they should be expanded. Reverting would send the wrong message "no, we want our stubs to stay stubby". —David Eppstein (talk) 18:47, 1 December 2014 (UTC)

I can understand your point of view--generally we don't want to reduce the usefulness of leads by cutting them down to single sentences. The Manual of style doesn't provide a lot of guidance for this. WP:LEADLENGTH says only that leads should be one or two paragraphs for articles of less than 15K characters. Wikipedia:Manual of Style/Lead section#Stubs says that sectioning of a stub should occur at an article length of 400-500 words. Some of the articles that Brirush has been sectioning have been shorter than this. But short articles often fit on a single screen, so there isn't much added cognitive friction in sectioning even short articles. I've looked at some of his recent edits and they seem fine to me. My guess is that Brirush is working very hard to improve the class of the mid and high importance articles in this project, a laudable goal. Sectionfying is a cheap way to help an article progress from 'stub' to 'start' class. So I'd recommend looking at each article on a case by case basis and if the sectioning has truly harmed understanding, unsectionfy and discuss on the article's talk page. --Mark viking (talk) 21:32, 1 December 2014 (UTC)

I went through and did more work on these articles (arithmetic topology, arithmetic combinatorics, topological combinatorics). If you find any more that are especially bad, let me know.Brirush (talk)

I undid your topological combinatorics one, but less because sectionifying was wrong there (it's a good length to have sections added and move from stub to start) and more because the text you added to make the sections flow seemed to me to misunderstand the subject. —David Eppstein (talk) 18:49, 3 December 2014 (UTC)

Thank youBrirush (talk) 00:44, 4 December 2014 (UTC)

merger proposal

We have a new article titled Legendre's formula, whose topic is the same as that of an old article titled de Polignac's formula. I've put "merge" tags on them. If they are merged, we have the question of what the title should be. Michael Hardy (talk) 23:53, 5 December 2014 (UTC)

Exponential broken up

Hi,

The article exponential map has been split into two articles: exponential map (Lie theory) and exponential map (Riemannian geometry) per the consensus at the talkpage, the original page having become the disambiguation page. It remains to fix a large number of incoming links. I did fix the most, but there are some instances when I couldn't figure out the correct targets. It seems many of them should have not be linked to the exponential map (a concept in differential geometry) to begin with. It would be nice if other editors with necessary background can take care of them. -- Taku (talk) 03:38, 6 December 2014 (UTC)

Maths ratings

I noticed that all Top-Class articles are rated B-class or higher. Are they really all at this level? Or is this an artifact from earlier, less restrictive rating requirements? In fact, I noticed that the maths rating "matrix" at Wikipedia:WikiProject_Mathematics/Wikipedia_1.0 is almost lower triangular.76.98.76.147 (talk) 00:46, 7 December 2014 (UTC)

I've noticed the same thing, but I've attributed it to editors' greater interest in more important topics and the relatively small number of articles on those topics. Ozob (talk) 02:59, 7 December 2014 (UTC)

Factorial categories

We're having a discussion at Talk:Factorial#Categories that started out being about some recent edits changing the categorization of that one article, but I think may be broadening to cover the proper relationship between Category:Factorial and binomial topics and Category:Gamma and related functions and their articles. The participation of additional knowledgeable participants would be helpful. —David Eppstein (talk) 06:08, 7 December 2014 (UTC)

Launch of WikiProject Wikidata for research

Hi, this is to let you know that we've launched WikiProject Wikidata for research in order to stimulate a closer interaction between Wikidata and research, both on a technical and a community level. As a first activity, we are drafting a research proposal on the matter (cf. blog post). Your thoughts on and contributions to that would be most welcome! Thanks, -- Daniel Mietchen (talk) 02:15, 9 December 2014 (UTC)

Concerns over the lead at Fourier transform

An editor has expressed concern over the lead at Fourier transform. Comments are welcome at Talk:Fourier transform#‎Lead. Sławomir Biały (talk) 13:04, 26 November 2014 (UTC)

Several editors have expressed concern about the FT lead. Grandma (talk) 14:43, 26 November 2014 (UTC)

Indeed, over the course of the years, editors have expressed many concerns about the lead. I am here referring to the discussion of the present form of the lead. Only one editor (you) has expressed concerns about that, and they have not been terribly constructive. Sławomir Biały (talk) 15:06, 26 November 2014 (UTC)

User:I'm your Grandma. is acting rather disruptively at the talk page now. I had refactored the section on periodic and transient phenomena, forking out a new section that concerned the lead as a whole. She has insisted on merging these two sections, which makes no sense (presumably out of some sense of ownership) since the section Talk:Fourier transform#Lead has nothing at all to do with transient and periodic phenomena. Anyway, I don't wish to get involved in an edit war on the talk page there, but editors here should be aware that Grandma seems to be deliberately trying to scuttle the attempt to gather outside input. Sławomir Biały (talk) 16:03, 26 November 2014 (UTC)

I've been reverting further edits to the discussion page there as vandalism. More eyes would be helpful though. Sławomir Biały (talk) 16:29, 26 November 2014 (UTC)

I also encourage other editors to take a look at the lead of Fourier transform! Sincerely, Grandma (talk) 18:01, 26 November 2014 (UTC)

I could use some help dealing with "Grandma"'s continued trolling at that discussion page. Sławomir Biały (talk) 08:41, 9 December 2014 (UTC)

Open Access Reader, tool to find missing academic citations

Hi, I'm working on a project to find academic citations missing from Wikipedia, which I think might be useful for this Wikiproject. It's just a proof of concept right now, but if you have any ideas or feedback, that'd be really helpful at this early stage. Check it out: Open Access Reader.

EdSaperia (talk) 13:02, 9 December 2014 (UTC)

Waring's prime number conjecture

SuggestBot recently pointed me to the article linked above. It's extremely stubby (though better than the useless mathworld article it links), but before I work on it I wanted to check that I'm not missing anything obvious. The statement is just a weakening of the weak Goldbach conjecture, right? And as such, it follows from last year's papers by Helfgott (are they accepted to be correct?). Does anyone know of sources actually discussing this conjecture independently of weak Goldbach? Perhaps I will just merge and redirect it there.... Any thoughts welcome. --JBL (talk) 04:38, 10 December 2014 (UTC)

I have no idea about Helfgott but I'd support a merge to Goldbach's weak conjecture which is much more complete and as you say appears to be on almost the same problem. The main thing I'd want to find out before merging (so it could be included) is: why Waring? How did his name come to be associated with this? —David Eppstein (talk) 04:47, 10 December 2014 (UTC)

This is a particularly good question because the one reference in the article doesn't mention Waring. A quick internet search is not instructive. --JBL (talk) 04:58, 10 December 2014 (UTC)

Equilateral hexagon

In Equilateral pentagon it is available to calculate the values of three of the internal angles as a function of the values of the other two angles. Then is it available to calculate the values of three of the internal angles in Equilateral hexagon when I know the other three angles? --Eric4266 (talk) 11:09, 11 December 2014 (UTC)

If three adjacent angles of an equilateral hexagon are known, then that determines the distances between the other three vertices. There will then be two possible locations for the middle one of those vertices. In other words, there will be two solutions for the other three angles (with a degenerate special case when you have a straight angle). JRSpriggs (talk) 16:46, 11 December 2014 (UTC)

Deletion of Fork (topology)

Deletion of Fork (topology) has been proposed. Michael Hardy (talk) 18:55, 11 December 2014 (UTC)

Why no standard Wikiproject tag?

Why don't you use a standard Wikiproject tag? Why should this one Wikiproject be different than every single other one? This makes things more difficult for new page patrollers and the like. Oiyarbepsy (talk) 07:16, 11 December 2014 (UTC)

You mean, why is our standard Wikiproject tag called {{maths rating}} and not something else more...standard? History and inertia, I assume. But also, if you look at the should-not-be-used {{WikiProject Mathematics}} you will see another reason: because it is (or at least at some point was) the consensus of the project that indiscriminately tagging articles by project without also rating them is useless — we have a bot-maintained list of articles that does a better job of identifying project-related articles than the banners do. As for new-page patrolling, see Wikipedia:WikiProject Mathematics/Current activity. —David Eppstein (talk) 07:24, 11 December 2014 (UTC)

Well, as long as the bot alerts you to new articles. I place the Wikiproject tags on all new articles I encounter so the WikiProjects who know the subject will see that there's a new article, but if your bot handles it, it's fine. Oiyarbepsy (talk) 07:30, 11 December 2014 (UTC)

The bot can miss things, mostly when they're not appropriately categorized. (If the category is added later, the bot will treat the article as new.) So catching and fixing those errors is definitely helpful. —David Eppstein (talk) 07:38, 11 December 2014 (UTC)

One qualm I've had about that bot is that its maintenance is wholly the work of one person rather than a crowd-sourced thing. If anything happens to him, the Universe will collapse (or at least those who follow our "current activities" page will no longer be able to do so). Michael Hardy (talk) 18:58, 11 December 2014 (UTC)

\not in MathJax puts the slash in the wrong place

With MathJax as my preferred rendering style (in Chrome on OS X), anomalous cancellation does not appear correctly: the slashes are placed near the digits they are supposed to be through. I.e. $\not {3}$ (<math>\not{3}</math>) renders as "/3" rather than as a slashed three. With the new MathML/SVG rendering it looks ok, so this is just MathJax. This does not happen when I use MathJax on web sites that I control, with the script from http://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML, so I'm guessing it must be something Wikipedia is doing differently than the standard MathJax that screws it up, or possibly a bug in an older version of MathJax that's being used here. Anyone here have any idea what the problem is, how to communicate the existence of the problem to the people who maintain Wikipedia's MathJax interface, and how to persuade them to actually fix it? And/or, whether there's some way of working around this that still renders correctly in the other styles? —David Eppstein (talk) 23:50, 6 December 2014 (UTC)

Presumably here https://www.mediawiki.org/wiki/Extension_talk:Math? I wonder whether we are going to use mathjax or mathml. (For me the "mathml" option works the best.) -- Taku (talk) 03:46, 7 December 2014 (UTC)

Thanks for the suggestion; I left a pointer there to the discussion here. —David Eppstein (talk) 05:16, 7 December 2014 (UTC)

It curiously only fails with numbers $\not 3$ and works with letters $\not B$. Looking at the generated code

<span class="mn" id="MathJax-Span-23" style="font-family: MathJax_Main; padding-left: 0.298em;">3</span>

there is a padding-left on the three which shifts it right. My guess is that this is a MathJax bug which has been fixed in the latest version but not version of MathJax we use.--Salix alba (talk): 07:44, 7 December 2014 (UTC)

An experiment:

$a\not \in A\,$

Michael Hardy (talk) 18:59, 11 December 2014 (UTC)

Strange notation in Proof that π is irrational

I'm a bit rushed or I would try to figure out what _ought_ to appear where this appears in Proof_that_π_is_irrational#Hermite.27s_proof:

$\overbrace {\left.\int _{0}^{1}(1-z^{2})^{n+1}{\frac {\sin(xz)}{x}}\right|_{z=0}^{z=1}} ^{=\,0}$

Michael Hardy (talk) 19:40, 12 December 2014 (UTC)

I would assume that it's merely stating that that part of the formula is equal to zero and its removal leads to the simplification in the next line. No? —David Eppstein (talk) 20:17, 12 December 2014 (UTC)

Perhaps this is obvious, but there shouldn't be the integral sign (it's a boundary term after integration by parts.) . -- Taku (talk)

Oh, you mean that aspect of the notation: the fact that it has both an integral sign and a vertical bar, and no d? Yes, I think including the integral sign is a mistake. —David Eppstein (talk) 21:52, 12 December 2014 (UTC)

OK, now I've looked at it while not distracted by pressing things, and I've made the obvious correction. Michael Hardy (talk) 23:55, 12 December 2014 (UTC)

Israel Gelfand's Shapiro companions

Are Ilya Piatetski-Shapiro, coauthor of

Gelfand, I. M.; Graev, M. I.; Pyatetskii-Shapiro, I. I. (1969), Representation theory and automorphic functions, Academic Press, ISBN 0-12-279506-7

and Z. Ya Shapiro, coauthor of

Gelfand, I.M.; Minlos, R.A.; Shapiro, Z. Ya. (1963), Representations of the Rotation and Lorentz Groups and their Applications, New York: Pergamon Press

the same person? YohanN7 (talk) 08:03, 12 December 2014 (UTC)

No. According to MathSciNet, Ilya Piatetski-Shapiro has MR Author ID 139240, while Z. Ya Shapiro has MR Author ID 264360. Boris Tsirelson (talk) 06:45, 13 December 2014 (UTC)

Thank you. I thought maybe something had gotten lost in translations, since the subjects are closely related and were some of Gelfand's main interests at that time. (Next time I'll know where to look.) YohanN7 (talk) 07:44, 13 December 2014 (UTC)

I understand your doubt. But MathSciNet usually knows who is who. Boris Tsirelson (talk) 09:25, 13 December 2014 (UTC)

Euclidean algorithm

I have nominated Euclidean algorithm for a featured article review here. Please join the discussion on whether this article meets featured article criteria. Articles are typically reviewed for two weeks. If substantial concerns are not addressed during the review period, the article will be moved to the Featured Article Removal Candidates list for a further period, where editors may declare "Keep" or "Delist" the article's featured status. The instructions for the review process are here. — Preceding unsigned comment added by ‎DrKiernan (talk • contribs)

Seems like more anti-intellectualism from our friends in the wider Wikipedia community (anyone remember the ridiculous affair that the mathematical works of Alexander Grothendieck should be made accessible to laymen?) Now we are told that the article on the Euclidean algorithm should be made understandable to 10 year old children! Sławomir Biały (talk) 13:53, 6 December 2014 (UTC)

I think commenting on this nomination is worthwhile. Explaining and promoting mathematics to the widest community possible is important. More generally, Wikiarticles can often be structured so that there is something in them for general public as well as, when necessary, something in them for the expert. My thoughts, sincerely, Grandma (talk) 14:27, 6 December 2014 (UTC)

It's not a particularly good article. Anyone reading the whole thing risks to die from boredom. YohanN7 (talk) 14:54, 6 December 2014 (UTC)

Parts of it are boring to me as well. Perhaps not the best article to nominate? Or, maybe because it needs work, it would benefit from the scrutiny that comes with nomination? Grandma (talk) 15:07, 6 December 2014 (UTC)

Why waste time on an article that is already (undeservedly) FA-class? Yes, surely there must be other better suited. But I can't think of a single math article that is very likely to appear as a featured article (except articles about mathematicians). YohanN7 (talk) 15:26, 6 December 2014 (UTC)

I agree, the article can be improved. Nothing about the FA designation implies that the article is perfect. But the reasons for nominating it for review are thoroughly idiotic (an easily Googled fact tag, and a belief that the article should be accessible to 10 year olds). A review can be constructive, with thoughtful comments that lead to real improvements. But that didn't happen here. Sławomir Biały (talk) 19:00, 6 December 2014 (UTC)

Can we please keep the rhetoric conducive to teamwork? Thank you, Grandma (talk) 19:29, 6 December 2014 (UTC)

Grandma, I'm not sure what you hope to accomplish by your continued trolling, but I'm pretty sure "teamwork" is not high on the list. Sławomir Biały (talk) 19:47, 6 December 2014 (UTC)

Is there any reason to limit the inputs to two integers? I would think that one could start with any finite number of real numbers. Take their absolute values. Sort by size. Remove zero and any duplicates. Then begin a loop where you replace the largest number by the difference between the largest and the second largest and then resort and remove duplicates (if any). It terminates when there is only one number left (the GCD). No guarantees that it will terminate. JRSpriggs (talk) 10:17, 7 December 2014 (UTC)

The termination is almost exactly the definition of commensurable. This algorithm is not new, but it is slower than computing first the GCD of the two smallest entries, and then iterate (slower because of more operations involving two large integers).

To editor Sławomir Biały: I have not seen anywhere that "we are told that the article on the Euclidean algorithm should be made understandable to 10 year old children". However Euclidean algorithm is one of the rare important mathematical results that can been told to 10 year old children: It suffices to known long division to introduce it in the modern form using Euclidean division, and this is not even needed for the version by subtractions, which requires only to understand what is a divisor. The concept of GCD is not even required as a background, as Euclidean algorithm is the most elementary way to define GCD's and prove their existence (The set of common divisors is not changed when running the algorithm, and at the end, one gets the set of all divisors of the single remaining integer). It is a pity that the article is written in a style which makes elementary notions unnecessarily obscure for the layman. D.Lazard (talk) 11:38, 7 December 2014 (UTC)

Dr. Lazard, I do not see the problem with the style of the article that others are complaining about. This is not to say that this or that could not be rewritten in a different style, but I don't see any problems with the style that obviously need fixing, especially not to the extent that the article deserves to be dragged to FA review. Making the article accessible to a 10 year old, for whom even a capacity for reading at an advanced level is rather unlikely, is an unreasonable standard for any encyclopedia article, let alone one about a mathematical algorithm. I am aware that some young persons may learn this algorithm from textbooks which are written for one of such a reading and mathematical level, but I highly doubt that an encyclopedia article would benefit from being rewritten in such a style. There is a project "simple Wikipedia" that is more appropriate for such an undertaking. Sławomir Biały (talk) 15:26, 7 December 2014 (UTC)

Sławomir Biały, where was "understandable to 10 year old children" first brought up with respect to this Euclidean article? Or is this your interpretation of what is expected? Grandma (talk) 16:11, 7 December 2014 (UTC)

[1] Sławomir Biały (talk) 16:26, 7 December 2014 (UTC)

And that is not the same as saying that "the Euclidean algorithm should be made understandable to 10 year old children". Some material in the article should, yes, be accessible to the typical reader, and some material can be there for the expert. Grandma (talk) 16:31, 7 December 2014 (UTC)

"Grandma", for someone who pays lip service to the idea of "teamwork", you have almost nothing to add to a productive discussion. The single "fact" tag for which the article was brought to FAR has been fixed (by me). Apart from some vague statement that the article should be more accessible (the only target anyone has identified is a 10 year old, a clearly ridiculous standard). If no one actally has anything concerte to add, I propose that we close the FAR as resolved. Sławomir Biały (talk) 16:38, 7 December 2014 (UTC)

I oppose to close the FAR. The article is full of unresolved issues. Here are some of the main ones.

• Before my today edit, the article did not mention one of the most important applications (important, at least, by the computer time devoted to it), the reduction of fractions. I have added it in the lead, but it deserves a section.
• Section "Bezout's identity" presents a method for computing it. I do not know if it is WP:OR, but I am sure that nobody uses it, as extended Euclidean algorithm is much more efficient and easier to use.
• In the applications, the distinction is unclear between the applications of Euclidean algorithm and those of extended Euclidean algorithm. Extended Euclidean algorithm is introduced only after using it several times (such as in "Bézout's identity" section).
• The section on polynomial Euclidean algorithm is very poor (compare with sections "Univariate polynomials with coefficients in a field" and "Pseudo-remainder sequences" of Polynomial greatest common divisor. It is not even said that polynomial Euclidean algorithm is fundamental for testing multiple roots and polynomial factorization. Undue weight is given to Sturm chains, that are not an application of Euclidean algorithm, but a variant of it (this is not said).
• The section "Generalizations to other mathematical structures" contains a confusing description of Gröbner bases. It says that it is a Generalization of Euclidean algorithm, which is historically wrong, as the connection between them has been discovered 7 years after the introduction of Gröbner bases. The important fact is not even given, namely that the polynomial Euclidean algorithm and Gaussian elimination are two special cases of Gröbner basis computations.

This only some of the many issues of this article. Considering them as minor would give a bad opinion of our community to external people. D.Lazard (talk) 19:17, 7 December 2014 (UTC)

These comments should really appear on Wikipedia:Featured article review/Euclidean algorithm/archive1 so it becomes part of the review process.--Salix alba (talk): 23:15, 7 December 2014 (UTC)

I mean no offense, but this is not a particularly "exciting" article to read. In a sense, it is irrelevant whether the article is understandable to 10-year-old boys and girls since they will not be reading it in the first place. In fact, it is not clear to me what the target audience of the article is. Wikipedia articles are meant for college-educated or college-being-educated "adults"-those who already known gcd. Thus, in principle, it is not necessary to write them like textbooks that are used in elementary schools. But we "could" choose to make the article accessible to children, but then as pointed out above, it's much better to start without gcd; the algorithm is simpler than the concept (I suppose.)

If the article is meant for more sophisticated readers, then it still fails them. I'm thinking of a para from the article like this one (excuse me for a long quote):

The fundamental theorem of arithmetic applies to any Euclidean domain: Any number from a Euclidean domain can be factored uniquely into irreducible elements. Any Euclidean domain is a unique factorization domain (UFD), although the converse is not true. The Euclidean domains and the UFD's are subclasses of the GCD domains, domains in which a greatest common divisor of two numbers always exists. In other words, a greatest common divisor may exist (for all pairs of elements in a domain), although it may not be possible to find it using a Euclidean algorithm. A Euclidean domain is always a principal ideal domain (PID), an integral domain in which every ideal is a principal ideal. Again, the converse is not true: not every PID is a Euclidean domain.

Again, who would be reading this? The majority of non-math major students need not learn about the distinction between lovely ring-alphabets: UFD, PID, GCD, etc. And why is this in the article "Euclidean algorithm"? Especially, the mention of GCD domains is problematic; it's only interesting to students in "ring theory". It's quite remarkable that the existence of GCD can guarantee that the domain is an integrally closed domain. But there is no need for a student to start to think about GCD domains before he (usually not she) learns about integrally closed domains.

In short, it's not clear to me what reader would enjoy reading this article. -- Taku (talk) 22:02, 7 December 2014 (UTC)

In the UK we start talking about GCD in Key Stage 3, 11 - 14 years old. I would say there is a good number of children in that age group who would try to read this article. So there is a good case for targeting some of the article at that age group. I think it does that quite well. The article much also pass WP:FACR in particular 1b: comprehensive. This means it must include advanced material which such children will not be able to follow.--Salix alba (talk): 23:10, 7 December 2014 (UTC)

A bit off topic but its not just the wikipeidia community which has problems with maths. Nature has just rejected an Obit of Alexander Grothendieck by David Mumford and John Tate for being too technical.[2] --Salix alba (talk): 09:41, 16 December 2014 (UTC)

Intriguing: Tsirelson's rogue edits

According to Daqu,

Tsirelson is known for undoing other people's Wikiedia edits without explaining his reasons for doing so.

If you are intrigued, see this edit, with the summary "Added fact about Tsirelson's rogue edits of Wikipedia". See also here and here. --Boris Tsirelson (talk) 09:53, 16 December 2014 (UTC)

Intriguing indeed. @Daqu: surely you must have an explanation. I see no reverts of your edits unless you have edited as an ip. YohanN7 (talk) 10:53, 16 December 2014 (UTC)

It surely must be intended as a joke. Unfortunately, on the internet the line between humor and psychopathic behavior is often not very clear. Sławomir Biały (talk) 12:10, 16 December 2014 (UTC)

Notification of merger proposal

I propose to merge Stern–Brocot tree and Calkin–Wilf tree, as they appear to be exactly the same tree. I have no opinion for the name of the merged article. I notify this project because of the low number of readers and watchers for both pages. I have opened the discussion at Talk:Stern–Brocot tree#Merger proposal. D.Lazard (talk) 18:00, 16 December 2014 (UTC)

Discussion of the merits of this proposal can continue at that talk page, but I would like to point out a factual error in your announcement here: these are not the same tree as each other. For instance, the children of 1/2 are different. —David Eppstein (talk) 18:33, 16 December 2014 (UTC)

Notification of Request for comments

I have opened a request for comments at Talk:Euclidean algorithm#Request for comments. D.Lazard (talk) 11:39, 19 December 2014 (UTC)

Two drafts for review

These two drafts were submitted today and look promising:

• User:Cleary83/sandbox (matrix regularization)
• User:Kjross/sandbox (loss function surrogates for classification)

Math topics aren't my forte on Wikipedia, so I'm posting these here if anyone has any comments or wants to review them. Thanks, ~SuperHamster Talk Contribs 06:12, 21 December 2014 (UTC)

Frame (signal processing)

Should the new article titled Frame (signal processing) be merged into Frame of a vector space? Michael Hardy (talk) 21:15, 21 December 2014 (UTC)

A merge does seem appropriate. For what it's worth, I think the new article frame (signal processing) is written in a much clearer style than frame of a vector space. Sławomir Biały (talk) 15:00, 26 December 2014 (UTC)

On a related note, Frame (linear algebra) probably should be a disambig page; in fact, it's already written that way. -- Taku (talk) 23:08, 26 December 2014 (UTC)

Recent activity at Talk:Quantum Mechanics

Hi!

There has been a storm of activity the past week (by few authors). I think we need more to chip in since the article is (ought to be) pretty vital in physics (and mathematics by extension to today's math-infested QM applications). The interested could perhaps have a look at Talk:Quantum mechanics#1920s quantum mechanics not obsolete. YohanN7 (talk) 11:59, 29 December 2014 (UTC)

WikiCup 2015

Hi there; this is just a quick note to let you all know that the 2015 WikiCup will begin on January 1st. The WikiCup is an annual competition to encourage high-quality contributions to Wikipedia by adding a little friendly competition to editing. At the time of writing, more than fifty users have signed up to take part in the competition; interested parties, no matter their level of experience or their editing interests, are warmly invited to sign up. Questions are welcome on the WikiCup talk page. Thanks! Miyagawa (talk) 21:53, 29 December 2014 (UTC)

Navier – Stokes Millennium Prize Problem. Alternative Solution

Well-known crank. See [3]
The following discussion has been closed. Please do not modify it.
Dear members of the world mathematical community! Enyokoyama (talk) (15:12, 8 November 2013) has offered the new section http://en.wiki.x.io/wiki/Talk:Navier%E2%80%93Stokes_existence_and_smoothness#Yet_another_solution_proposed.3F As a result of discussing this section http://en.wiki.x.io/wiki/Talk:Navier%E2%80%93Stokes_existence_and_smoothness#Attempt_at_solution.5Bedit.5D has been proposed for improvements to the Navier–Stokes existence and smoothness article: Attempt at solution Classical solutions In 2013, Mukhtarbay Otelbaev of the Eurasian National University in Astana, Kazakhstan, proposed a solution. As an attempt to solve an important open problem, the proof was immediately inspected by others in the field, who found at least one serious flaw. Otelbaev is attempting to fix the proof, but other mathematicians are skeptical. Alternative solutions Terence Tao in 18 March, 2007 announced three possible strategies of an alternative solutions if one wants to solve the full Millennium Prize problem for the 3-dimensional Navier-Stokes equation. Strategy 1 “Solve the Navier-Stokes equation exactly and explicitly (or at least transform this equation exactly and explicitly to a simpler equation)” is used in these works: Navier –Stokes First Exact Transformation (3 pages) Navier –Stokes Second Exact Transformation (5 pages) The author of these brief notes Alexandr Kozachok (Kiev, Ukraine) has offered (in February 2008 – Internet , in 2008, 2010, 2012 – INTERNATIONAL CONFERENCE reports, in November 2013 and February 2014 - INTERNATIONAL journal) two exact transformations to the simpler equations. These transformations are executed by well-known classical methods of mathematical physics. Therefore not only some professionals, but also educational, social and many other sites have republished or paid attention to these works . Read more http://en.wiki.x.io/wiki/Talk:Navier%E2%80%93Stokes_existence_and_smoothness#Attempt_at_solution.5Bedit.5D However the Wiki editors can not deny “Alternative solutions” but only block any information about this work. Therefore let's formulate your position for editing of the “Attempt at solution” section http://en.wiki.x.io/wiki/Navier%E2%80%93Stokes_existence_and_smoothness#Attempt_at_solution 93.74.76.101 (talk) 11:37, 29 December 2014 (UTC)

The above shows that our old friend Continuum-paradoxes (talk · contribs · deleted contribs · logs · filter log · block user · block log) is back (and apparently editing under various IPs). He is no longer limiting his contributions to discussion pages, so it might be good for project participants to keep an eye on Navier-Stokes related articles (and other articles that this crank might attempt to push his OR). Sławomir Biały (talk) 01:52, 30 December 2014 (UTC)