Wikipedia talk:WikiProject Mathematics/Archive/2013/Jul

Comments requested

Perhaps you'd like to weigh in here, so that the review can be conducted appropriately. Regards, FoCuSandLeArN (talk) 17:55, 27 June 2013 (UTC)

AfC entry on the infamous Boubaker polynomials, created by and edited by Tunsian IP addresses (with a newly registered account joining in the fun). This is the same pattern as M. Boubaker's previous attempts to create this article. Sławomir Biały (talk) 19:04, 27 June 2013 (UTC)

Boubaker is definitely back, socks and all. See Lattice Compatibility Theory and Wikipedia:Articles for deletion/Lattice Compatibility Theory. Sławomir Biały (talk) 19:25, 1 July 2013 (UTC)

Template: Functions

I made a medium-sized sidebar for concepts related to functions. It links to several articles written in the “this thing is used for so and such” style, three written by me and one by Maschen, but now there is a sufficient number of these articles to make a navbox. Also note title= pop-ups in the “by domain and codomain” section.

Could somebody review it? May I start to transclude it to articles? Incnis Mrsi (talk) 16:28, 30 June 2013 (UTC)

Needs some work. Putting text in the image field has spacing issues. Also, old-style HTML attributes only accept integers (without the "px"). Those parameters (cellpadding, cellspacing) should not be used without their companion CSS counterparts in the style(s) parameter anyway. — Edokter (talk) — 17:45, 30 June 2013 (UTC)

Incnis Mrsi - you should be prepared that people will complain about sidebars and probably request them to be navboxes as footers (see for example template talk:Tensors#Navboxes should be at the bottom). The reasons are that

• all links in it can be seen at a glance,
• takes up less space when expanded and no images on the right-side of the article will be pushed around (see for example notation for differentiation),
• pictures can be placed in the top-right corner of the article in the lead.

Just some thoughts. Thanks for its creation, M∧Ŝc²ħεИ_τlk 09:17, 1 July 2013 (UTC)

I am far less interested in what Jorge Stolfi thinks about this than in what you think about this. “Less space when expanded” – doubtful, “no images on the right-side of the article will be pushed around” – let’s hope that the sidebar will not placed by imbeciles. Pictures – yes, then can, so what? Incnis Mrsi (talk) 09:59, 1 July 2013 (UTC)

The tensor template was not converted to a footer only because of Jorge Stolfi's unpersuasive personal opinions, there were suggestions from others, and the new layout does look like an improvement. This is not something that should generally be done - just providing a pointer for something else to consider. M∧Ŝc²ħεИ_τlk 10:22, 1 July 2013 (UTC)

While I appreciate what the template is trying to achieve, I find the arrow notation to be kludgy and unattractive. This has not been improved by the recent change from a single glyph → to the two glyphs —›. (This will not stand for Wikipedia's cadre of unicode consortium hatchetmen, but my principal objection is that it is simply ugly.) Why not simply link the relevant articles? (A more attractive graphical solution would be to use LaTeX to produce an image, and then use the {{Image label}} template to insert links to the image, but maybe this is overkill.) Sławomir Biały (talk) 20:51, 1 July 2013 (UTC)

I actually like Incnis' original idea of arrows from and to the spaces, as well as the overall layout. But since most other people will object, it should probably just be the usual layout of links in collapsed entries like template:calculus (boring but at least effective). M∧Ŝc²ħεИ_τlk 20:59, 1 July 2013 (UTC)

Names of some of these articles are too verbose to fit into the table. Did you notice the table structure, I hope? Image labels is a stillborn idea: non-distinctive boldface for → in my sans serif was exactly the reason why I replaced it with other characters that have distinctive boldface variants. Incnis Mrsi (talk) 17:49, 2 July 2013 (UTC)

Must we justify every single use of Escher's drawing separately?

At Poincaré disk model, Werieth (talk · contribs) removed the link to M. C. Escher, Circle Limit III, 1959 saying "files are missing non-free use rationale's for this article". But a rationale for Hyperbolic geometry is listed and the example there is more specifically an instance of the Poincaré disk model of hyperbolic geometry. So do we really have to generate a separate justification for this article? JRSpriggs (talk) 01:55, 3 July 2013 (UTC)

Yeah, I think so. I don't think you have to be particularly original — if the justification for the hyperbolic-geometry article works just as well for this one, then just copy it, changing anything that needs changing. Unfortunately there are a lot of folks that don't believe in fair use at all (or at least don't think it should be used in en.wiki, which is admittedly not the same thing), and as a consequence the rules are IMO unnecessarily restrictive, but nevertheless the rules. --Trovatore (talk) 02:03, 3 July 2013 (UTC)

For better or worse, the answer is yes. This is a combination of several factors: (1) Escher's works are all copyrighted. Although his works may seem older, he worked from 1937 until later that century, and modern copyright law has extended the copyrights from that era until far in the future. (2) The WP:NFCC policy is very strict and has the bureaucratic requirement of a separate rationale for each use. Having been previously involved on some of those pages, I can say (without judgment) that some editors have very strong feelings about it and are unlikely to make "exceptions".

I think it is often sufficient to link to the article on one of Escher's works. Although this adds an inconvenience to the reader, because they have to click to see the work, it eliminates most of the hassle of WP:NFCC. If a image is desired in a math article, the key is to include sourced commentary that specifically discusses the image, and add a rationale to the image page pointing out that commentary. — Carl (CBM · talk) 02:07, 3 July 2013 (UTC)

Unfortunately, unlike some of his other works, we do not have an article on M.C.Escher's circle limit III even though it is shown in his biography.

Another anomaly is that a rationale is listed for Tessellation, but the picture is not actually shown in the article on Tessellation. Also that rationale is interrupted by the {{Non-free 2D art}} template instead of being placed after it like the other rationales. JRSpriggs (talk) 02:57, 3 July 2013 (UTC)

I believe there are enough scholarly publications specifically about Circle Limit III to make it sufficiently notable for a stand-alone article, if someone wants to take the time and effort to make it one. —David Eppstein (talk) 03:22, 3 July 2013 (UTC)

Ok, done. —David Eppstein (talk) 07:28, 3 July 2013 (UTC)

Thanks to David Eppstein for creating Circle Limit III and fixing our image file's description. I added a link to the new article to Poincaré disk model to replace the direct invocation of image which was removed. I hope that keeps everyone happy. JRSpriggs (talk) 11:58, 3 July 2013 (UTC)

Quasi-separated morphism

Quasi-separated morphism is currently a redirect to Quasi-separated: I think it should be the other way round, but can't do the move. Spectral sequence (talk) 06:43, 6 July 2013 (UTC)

Change Similarity transformation redirect

Similarity transformation is supposed to link to the matrix similarity article, surely. It did at one time, then it was changed in subsequent edits. I'm going to change it back to matrix similarity, but does anyone have other ideas? M∧Ŝc²ħεИ_τlk 11:52, 4 July 2013 (UTC)

There is no idea of transformation in matrix similarity. On the other hand, "Similarity (geometry) [is] a shape-preserving transformation" (quote from similarity (disambiguation)). Therefore, IMO, your edit is wrong, and I'll revert it. D.Lazard (talk) 12:36, 4 July 2013 (UTC)

A similarity transformation is a matrix transformation of the form A -> P A P^-1.

Examples include:

• transformation of co-ordinate axes to the principal axes of the inertia spheroid, diagonalising the inertia matrix (Moment of inertia#Principal axes, or Principal Components Analysis in statistics);
• transformations to normal mode co-ordinates, diagonalising a quadratic form;
• transformations to "good quantum number" bases in quantum mechanics, diagonalising the Hamiltonian;
• use of rotors/quaternions/spin-matrices to effect rotations.

So of course Maschen is correct in that being where the redirect ought to point. Jheald (talk) 13:03, 4 July 2013 (UTC)

The acid test is to see what articles link to the page, and in what context, eg: Dirac equation, Positive-definite matrix, Representation theory of the Lorentz group, etc. Jheald (talk) 13:14, 4 July 2013 (UTC)

Similarity transformation is a common term in physics for what is essentially a change in basis. Maschen is correct that for physicists at least, it should redirect to matrix similarity. But D.Lazard is correct too, in that for math folk similarity transformation is first and foremost a geometric concept, one that everyone learns in high school. Wherever the redirect points to, there should be a hatnote pointing to the other major use of the term Similarity transformation. --Mark viking (talk) 14:24, 4 July 2013 (UTC)

I would qualify that. "Similarity" is a geometric concept that is taught in school -- whether two triangles are similar, etc. But I don't think I ever heard the phrase "similarity transformation" used in that connection. On the other hand for matrices and operators, similarity transformation is a very precise concept, and this is the phrase invariably used for it. Jheald (talk) 14:39, 4 July 2013 (UTC)

But here's a scientific dictionary that gives both senses [1], so it looks like we should probably have a dab page. Jheald (talk) 14:44, 4 July 2013 (UTC)

Or better, by WP:2DABS, this could be solved by hatnotes. In fact the dab page similarity (disambiguation) already exists and clearly distinguishes between these two meanings.

Jheald, A similarity transformation in geometry is an equally precise concept, referred to by precisely this name. It is a transformation of a geometric space (by default the Euclidean plane) that takes every shape to a similar shape. Similarity transformations are special cases of affine transformations and of Möbius transformations. Sometimes they are referred to just as "similarities", but that is more ambiguous, because "similarity" may also be the property of being similar. The change to this redirect broke one of the wikilinks in affine transformation, for instance, which was expecting to refer to the geometric concept. —David Eppstein (talk) 17:25, 4 July 2013 (UTC)

Sorry for breaking any links... Anyway since the term "similarity transformation" appears to be torn between a few articles why don't we just create a DAB page specifically for similarity transformation (yes, I know there is similarity (disambiguation) but that one is much more general) - with the links

• Similarity (geometry)
• Matrix similarity
• Affine transformation
• Möbius transformation

and "see also" pointers to transformation, similarity (disambiguation)? M∧Ŝc²ħεИ_τlk 18:30, 4 July 2013 (UTC)

Affine transformation should be a see-also, not a main link, and I'm not sure Möbius needs to be listed there at all. —David Eppstein (talk) 19:06, 4 July 2013 (UTC)

Done. M∧Ŝc²ħεИ_τlk 09:35, 6 July 2013 (UTC)

I've done a dab pass through the various links. I routed links for the Euclidean geometry concept through Similarity transformation (geometry), in case anyone wants to expand this, or point it to a specific part of the Similarity (geometry) article. Jheald (talk) 15:52, 7 July 2013 (UTC)

Thanks for doing that and sorry to create work for others, I didn't get round to fixing those myself through the "what links here" function in the toolbox... M∧Ŝc²ħεИ_τlk 21:46, 7 July 2013 (UTC)

Differentiable map is undefined

Differentiable map redirects to smooth function, which does not discuss or define differentiation of a continuous map between manifolds. ᛭ LokiClock (talk) 19:51, 6 July 2013 (UTC)

How do you get the redirect to go to the smooth functions between manifolds paragraph? AHusain314 02:21, 7 July 2013 (UTC)

Click on the Differentiable map link, then click on the "Redirected from" link at the top of the linked Smooth function article. Edit the redirect page to have the content #REDIRECT [[Smooth functions#Smooth functions between manifolds]]. However, this seems to be the wrong destination, as LokiClock points out: differentiable and smooth are not synonyms. — Quondum 03:00, 7 July 2013 (UTC)

I have redirected Differentiable map to Differentiable function, which is the correct target. However, this article unduly emphasizes on the univariate case and would need to be rewritten for better taking the multivariate case into account. D.Lazard (talk) 08:02, 7 July 2013 (UTC)

modular group visualization

I made a video showing how the Klein's j-invariant is invariant under tau->-1/tau in SL(2,R), and I would be happy to provide the movie file if someone else could convert it to an animation for this page:

Here it is on youtube: http://www.youtube.com/watch?v=kvQ7e2AiE2g

http://wiki.riteme.site/wiki/Modular_group

tryptographer (talk) 18:32, 7 July 2013 (UTC)

Transformed the redirect Irreducible representation into an article

Even just looking at the edit history, and more importantly after a discussion on my talk page, this is a desperately needed article and would help fill gaps in WP on group theory in theoretical physics and chemistry. I thought that at least something of a definition with some links and sources (to be moved inline) is far better than the annoying redirect to simple module, and decided put the draft in mainspace so others with expertise/interests in group theory can see and/or edit it. Needs a lot of work which I'll hopefully get to finish (recently busy...). M∧Ŝc²ħεИ_τlk 21:46, 7 July 2013 (UTC)

An irrep cannot be decomposed into a (non-trivial) tensor product, you said? You will write great textbooks some day in a distant future, but now start from learning the representation theory, please. Representation theory of the Lorentz group gives good examples, where e.g. the 4-vector representation is a tensor product of two complex conjugate spinor ones. The latter are projective reps of of the Lorentz group though, but for SL(2, C) they are true representations. And, surprisingly… the 4-vector rep has no invariant subspaces! Incnis Mrsi (talk) 03:46, 8 July 2013 (UTC)

Well, I can't follow the WP version of representation theory of the Lorentz group too easily, and there is a section on this to be expanded. If the irrep can be decomposed, doesn't that mean invariance is broken, somehow? Anyway it's something else I'll try to clear up soon... M∧Ŝc²ħεИ_τlk 05:49, 8 July 2013 (UTC)

I have written quite a lot of content on the topic of unitary representation theory. The article being discussed here seems like some sort of essay. It seems quite confused even in the lede. Groups like SL(2,C) are the complexifications of compact Lie groups like SU(2). The irreducible representations of compact Lie groups, in particular the classical groups, are a natural development of nineteenth century invariant theory. That subject was covered in the book of Felix Klein on the icosahedron and culminated in the work of Schur and Weyl. That theory was used in elementary particle theory by numerous authors. For finite groups it was used in crystallography. Infinite-dimensional irreducible representations, for example of the Heisenberg group, have played a central role in quantum mechanics (and later dual resonance models and String theory). Much of that development, also historically originating in the work of Weyl and von Neumann, is described in the lectures and books of George W. Mackey, which contain numerous instances of the applications of representation theory.

The current article gives a confused view of the topic and not enough sources. The statements on tensor products are strange. For finite groups or compact Lie groups, the irreducible representations of a direct product arise from taking tensor products of irreducible representations of the factors. In general, except in special cases, tensor products of irreducible representations are rarely reducible. The decomposition rules are generalizations of the Clebsch-Gordan formulas. For classical simple groups they can be described for fundamental representations (the Brauer-Weyl rule) or by the combinatorics of the Littlewood-Richardson rule and its generalizations.

Perhaps a good place to start is using a source like "The Scope and History of Commutative and Noncommutative Harmonic Analysis" by George Mackey. There is also no shortage of books with titles like "Lie groups for physicists". Mathsci (talk) 06:41, 8 July 2013 (UTC)

If the article and me are confused, then no surprise, but I wrote from Wigner, Tung, Weinberg, and Atkins (of course there could be more sources, but it's certainly better than nothing). The tensor product bit in the lead will be cut out, but all the sources just mentioned do give the similarity transformation and block matrix, so if nothing else I can't see why that would be wrong.

Apart from the sources and external links already there - the article may as well be scrapped and restarted... M∧Ŝc²ħεИ_τlk 07:37, 8 July 2013 (UTC)

It seems like the errors have been for the most part corrected. I'm not personally keen on the emphasis of the article on physics (a la Wigner), but I think it's obviously better that this article exist (irrespective of its general condition) than for it to be a redirect. It seems much more likely that someone will improve the article now that it exists. Sławomir Biały (talk) 20:07, 8 July 2013 (UTC)

Worse than the emphasis on physics, Maschen’s version is exclusively focused on groups. It is exactly as incorrect as the simple module redirect it recently replaced. The article has to be, at first, restructured to cope with this problem. Incnis Mrsi (talk) 13:30, 9 July 2013 (UTC)

@Incnis Mrsi: Slightly off-topic, but at WP:RD/MA (here) I have recently been trying to understand exactly what it means for spin representations to be called "projective", in terms of the definition given in the article projective representation. Despite valiant efforts by Sławomir Biały (talk · contribs) and an anonymous IP, I'm still not quite there yet. I'd be very grateful for any further clarifications anyone felt like offering there. Jheald (talk) 08:39, 8 July 2013 (UTC)

No longer an issue. All sorted out now. Jheald (talk) 13:40, 8 July 2013 (UTC)

"Reiteration" rule of inference

In mathematical logic, "reiteration" is a rule of inference. See our article on the deduction theorem#Virtual rules of inference and propositional calculus#Argument. However, Reiteration is at present merely a redirect to the musical concept Tremolo. I think we need at least a disambiguation (or hat note) here, and possibly an article. What do you-all think? JRSpriggs (talk) 10:52, 11 July 2013 (UTC)

I created a hatnote at Tremolo to point to the mathematical articles you link here, although a DAB page may be better if more than two pages are involved. M∧Ŝc²ħεИ_τlk 11:10, 11 July 2013 (UTC)

Maschen, as usually I see you running well ahead of schedule. Incnis Mrsi (talk) 11:14, 11 July 2013 (UTC)

Regardless of “virtual rules of inference”, the musical redirect on a word from a non-specific vocabulary is bad. Overwrite it with a dab boldly. Incnis Mrsi (talk) 11:14, 11 July 2013 (UTC)

As you can now see, my edit has been reverted. Let's just proceed with a DAB page. M∧Ŝc²ħεИ_τlk 13:51, 11 July 2013 (UTC)

Done. WikiProject Music has also been notified. Rather than trying and failing and wasting people's time fixing my errors, I'll leave it to the members of this project and WikiProject Music to fix any incoming links and double redirects to reiteration, as and when they are inclined. M∧Ŝc²ħεИ_τlk 14:05, 11 July 2013 (UTC)

Just in case someone wants to help with sourcing for 'Continuum hypothesis'

Please see Talk:Continuum hypothesis/Archive 1#Result by Laszlo Patai. -- Toshio Yamaguchi 13:16, 11 July 2013 (UTC)

Visual Editor changing how italics and superscripts interact

The new visual editor is much discussed, but theres one subtile change which affects html format maths equations. In this revision [2] its changed ''x''_''s'' to ''x_s''. Other changed have ''F''^''i''0 (Fⁱ⁰) to ''Fⁱ''⁰ (Fⁱ⁰) splitting one compound superscript into two. Other diffs on other articles have done the reverse. None of the edits actually change how the equation appear, so I'm not sure its a big issue. Its done to about 10 edits a day all of which seem to be tracked in and edit filter.[3] Anyway if anyone is interested in the issue there is a buzilla T52938.--Salix (talk): 22:31, 11 July 2013 (UTC)

I reported this to them back in June, it is bug 50291. — Carl (CBM · talk) 01:30, 12 July 2013 (UTC)

I have just realised that I am not using VE, presumably because I'm using an unsupported browser. Are other Project members using it for mathematical articles, and what are their reactions? Is there any risk that it will become compulsory and that I'll suddenly find myself unable to edit? Spectral sequence (talk) 17:11, 16 July 2013 (UTC)

canonical

Here is an old version of the article titled canonical. Here is the imbecilic current version. It was imperfect before, but written by somewhat literate people. Now it's just dishonest. Work on this is needed. Michael Hardy (talk) 05:55, 13 July 2013 (UTC)

The erosion of that article happened in several stages. First, apparently based on discussions on the talk page, it was converted to a dab. Then most of the disambiguation entries were removed. We can argue about whether the edit summary of that last edit was correct, but it was clearly a destructive edit. Sławomir Biały (talk) 06:16, 13 July 2013 (UTC)

IMHO the most imbecilic thing of the current version is this content dispute template on a WP:disambiguation page. Being serious, trace to which articles was the original content transferred, please, before starting a pointless flame. Incnis Mrsi (talk) 06:19, 13 July 2013 (UTC)

Well originally these were linked in the dab page. But now they aren't anymore. It's all well and good that this content exists somewhere, but not so good if readers are unable to find it. Sławomir Biały (talk) 06:27, 13 July 2013 (UTC)

This is highly inappropriate conduct from an administrator. I suggest User:Michael Hardy familiarises himself with correct template usage, and tone down the language. StAnselm (talk) 06:47, 13 July 2013 (UTC)

The solution is to replace, in canonical (disambiguation), the entry canonical form by canonical (mathematics) and to write this article, which should describe the various meanings of this word in mathematics. This article should link to canonical form but also define canonical morphism and canonical isomorphism (the unique morphism such that ...) for which I have found nothing in WP. The "Mathematics" section Here could be a starting stub for this article. D.Lazard (talk) 10:52, 13 July 2013 (UTC)

Systemic real numbers bias

One can easily notice that most math articles of en.wikipedia show a strong preference to the real numbers field. And not only in differential geometry where real numbers are deeply entrenched in most primary sources, but in other disciplines too, not excluding algebra. When the bias is explicated, it sometimes has grotesque forms such as presenting general facts as relevant to real numbers only: recall the scandal with the former “Euclidean subspace” article. But there is also a cryptic, more dangerous form of real bias where the field of scalars is not named at all in the relevant context: for example, see the Spin group article which discusses an accidental isomorphism of the Spin(2) and its action of R². I think that any article that presents a real-specific fact must have a mention of R in the appropriate place. Incnis Mrsi (talk) 14:33, 9 July 2013 (UTC)

About the "Euclidean scandal"... I, personally, would be glad to say (on my lectures) that the n-dim Euclidean space is (by definition) an affine space with (some additional structure). However I do not think this terminology is standard. Some mathematicians use both "vector Euclidean space" and "affine Euclidean space"; some use "Euclidean space" (by default, vector!) and "affine Euclidean space"; many use only "Euclidean space" (by default, vector); and very few use "Euclidean space" (by default, affine). Correct me if I am mistaken; I would be happier to be mistaken than right. Boris Tsirelson (talk) 15:18, 9 July 2013 (UTC)

This is sort of like complaining about a "systemic pine-tree bias" in the forests of Russia. I don't think there's any way around the fact that the reals are probably the most used field in math and physics, and therefore the most familiar and most prolific in texts. The complaint about leaving the assumption invisible is fair enough. Isn't the solution just to obviate the field being used? Rschwieb (talk) 16:51, 9 July 2013 (UTC)

How is it related to Tsirel’s comment? Incnis Mrsi (talk) 11:14, 11 July 2013 (UTC)

Dear @Incnis: I apparently made an indentation mistake. Please next time skip the process of writing comments feigning that you could not figure out that a certain comment was directed at you, and continue with addressing the comment. It will save all of us reading/writing time. Thanks. Rschwieb (talk) 13:23, 11 July 2013 (UTC)

Could you just fix the indentation instead of explaining than you made a mistake? Incnis Mrsi (talk) 13:41, 11 July 2013 (UTC)

Dear @Incnis: The answer is no. When the intention is abundantly clear, as it is here, I am not going to fix it. I thought I made that clear in my previous comment. Since I have abundant confidence in your ability to understand the intention, I won't fritter away time playing the "edit-Incnis's-nit" game in the future. Please stop trying to get me to play the game. Thank you for understanding. Rschwieb (talk) 11:32, 17 July 2013 (UTC)

Well, the reals are a pretty amazing field: They're the only Archimedean completion of the rationals, and so they (quite naturally) have a distinguished role in mathematics. It's always good to state your context and assumptions, but I think it's indisputable that R is more important than, say, Q₄₁. Ozob (talk) 03:02, 11 July 2013 (UTC)

This is more of a mathoverflow issue. If you raise the issue there, make sure to give your sources, be specific (with examples), and avoid subjective and argumentative comments. If you do so, please provide a link. Tkuvho (talk) 08:06, 11 July 2013 (UTC)

Please, make yourself familiar with http://mathoverflow.net/help/on-topic, and specifically the paragraphs about “well-defined questions” and “not a discussion forum”. Anyone asking a question on whether R is more important than Q₄₁ can count on my vote to close as “primarily opinion-based”.—Emil J. 11:08, 11 July 2013 (UTC)

I disappointed about the observed lack of serious consideration from the WikiProject’s members. Nobody refutes that R is important, but these are not real numbers that generates the overwhelming majority of abstract mathematical structures (the concept of metric space is the only structure I can remember that directly depends on reals). There is no guideline how to explicate the dependence on the field (or ring) of scalars, and there is nothing good with this in the present stage of Wikipedia. Incnis Mrsi (talk) 11:14, 11 July 2013 (UTC)

WP:MTAA. Making things as general as possible is all very well, but often what is most helpful to readers at least initially is something much more concrete and specific -- particularly if they need the maths, but don't have a maths background, and have not taken courses that might be standard in a mathematics degree but may not typically be found in degrees in other disciplines.

On a related note, Incis, I saw you recently replaced SO(3) with SO(3,R) and SO(n) with SO(n,F) in the examples section of Projective representation (diff) I am not sure that this was terribly useful. The point surely of an examples section like this is to present the material applied to particularly important and familiar cases. SO(n), and SO(3) in particular, is the case of key importance, because this corresponds to rotation of everyday Euclidean spaces, and in particular the 3D space in which we live. Also, because orthogonality is particularly associated with real matrices -- the relevant corresponding concept for complex matrices is usually unitarity instead. So in this case SO(n) and SO(3) were entirely appropriate, and were what should have been used. Making the notation more complicated than this just makes the article more opaque and more forbidding to likely readers, for no gain that they are likely to appreciate. Jheald (talk) 12:59, 11 July 2013 (UTC)

@User:Jheald: Accepted modern theories such as quantum mechanics emphatically deny that the world "in which we live", as you put it, has the structure of a vector space over a field built using Dedekind cuts, so in a way the tenor of your comment confirms some of User:Incnis Mrsi's concerns. Tkuvho (talk) 13:13, 11 July 2013 (UTC)

(ec) Part of the skill of making a mathematical model (or a physical model) is choosing the right variables, that transform in the right way. For a vast swathe of applications, that means a classical conventional real space. Besides, User:Incnis Mrsi's obfuscations to that article wouldn't help anyone understand quantum mechanics any better. Jheald (talk) 13:23, 11 July 2013 (UTC)

To which article? Incnis Mrsi (talk) 13:41, 11 July 2013 (UTC)

Really?? It seems I miss something important in quantum theory... Could you tell a bit more on this point?

I'd say, the question is, whether or not real numbers are significantly more notable than others. Boris Tsirelson (talk) 13:20, 11 July 2013 (UTC)

I don't think anyone disagrees the reals are significantly more notable. First of all, the 90+% of people who are not mathematically minded only "know" about two or maybe three fields, and the reals is definitely going to be one of them (even if they have a poor conception of it.) And then even among mathematicians, R is still regarded as a significant field. I think the question(s) are more along the lines of "Do we need to broaden some articles away from R?" and then "If so, which ones?". Rschwieb (talk) 13:32, 11 July 2013 (UTC)

@User:Tsirel: In our article Introduction to quantum mechanics, one finds the following: "Some aspects of quantum mechanics can seem counter-intuitive or even paradoxical, because they describe behaviour quite different than that seen at larger length scales." Meanwhile, the real line assumes scale homogeneity and infinite divisibility, and therefore does not reflect the phenomena on very small scales. I am sure you are aware of this, and I agree, along with User:Incnis Mrsi, that as you put it the "real numbers are significantly more notable than others". Tkuvho (talk) 13:29, 11 July 2013 (UTC)

No, sorry, this is an oversimplification. It is well-understood that the quantum/classical border is related not to the size of the objects, but to decoherence. True, decoherence is typically very strong for large objects and weak for small objects. However, this is not a failure of scale homoheneity of the space. Quantum physics is evidently scale inhomogeneous, indeed. But not the space (unless you come to such ideas as the Planck scale foam). Boris Tsirelson (talk) 14:52, 11 July 2013 (UTC)

Are you arguing that physical space is scale homogeneous? I wonder how you know that :-) What happens exactly on the scale below the smallest string? Tkuvho (talk) 15:03, 11 July 2013 (UTC)

BTW I do not trust in “the space-time”. Although Lorentz symmetry is observable in numerous its manifestations, there are little evidences that “points of the space-time” actually have sense on a fundamental level. What is certain is that there is no observable evidences of the scale symmetry. Incnis Mrsi (talk) 15:07, 11 July 2013 (UTC)

"modern theories such as quantum mechanics emphatically deny" is one thing, and "there are little evidences" is a quite different thing. :-) Boris Tsirelson (talk) 16:21, 11 July 2013 (UTC)

Formulation of a projective representation over an arbitrary field belonged to the article long before my edit. I stressed that the choice of real numbers has nothing to do with the double cover stuff, but the concrete rotation group is 3-dimensional and real, not any else. How the article become opaque from the edit when the wikilink rotation group SO(3) lies behind the symbols? Incnis Mrsi (talk) 13:41, 11 July 2013 (UTC)

It sounds to me like you want to be able to do all of mathematics (well, the part of mathematics that requires fields) over an arbitrary ground field k. It won't work. You cannot even expect the same behavior from R and C (compare real differentiable functions to complex differentiable functions); let alone Q_p and R(x) and F_p and so many others. It's nice to unify things where possible and where it retains clarity, and there are plenty of situations that could be treated in a unified way that aren't currently in Wikipedia; but you can't expect to banish the mention of specific fields, even in those contexts where the definitions don't require a specific field. Ozob (talk) 13:42, 11 July 2013 (UTC)

@User:Ozob: I am not sure why such a rush to refute User:Incnis Mrsi. It may be more helpful to ask for a clarification of what he wishes to improve, for example, in the case of the Spin group. I personally have the impression that the real case is the most important case here, but perhaps I am not sufficiently familiar with the literature. Some examples would be helpful. But the sarcasm and animosity that's coming from a number of editors is a bit puzzling. Does it make people lose sleep just to conceive of the idea that there might be a systemic bias in favor of the reals? Tkuvho (talk) 13:51, 11 July 2013 (UTC)

Despite my opposition to User:Incnis Mrsi on the issue of Euclidean space apropos of our article manifold, I agree with the contention that Spin group (and other similar articles in group theory) should be quite clear from the outset what the relevant field is. However, I also agree with Rschweib's "sarcasm" (as you put it) to a certain extent. I would not characterize this as a systemic bias, but rather just poor encyclopedia writing. For example, I would not want to see the article spin group rewritten from the perspective of group schemes, although at a minimum the field(s) involved should be emphasized. I think the "bias" in restricting to the real field (and complex field as well) in many cases is consistent with the appropriate WP:WEIGHT. This is essentially what I have already said at Talk:Manifold when a similar issue was raised. Sławomir Biały (talk) 14:08, 11 July 2013 (UTC)

(edit conflict) The content on algebraic groups is not great on wikipedia even over the complex numbers. Where for example is the fixed point theorem for solvable groups acting on a projective variety? (is it hidden away somewhere in Borel subgroup?) There are plenty of sources (Chevalley, Borel, Humphreys). As far as differential geometry is concerned, one fairly common way to give a clear exposition is to use matrix groups (so algebraic if compact). Otherwise there is an unnecessary and off-putting amount of preparatory material required to define Lie groups and the exponential map. The problem already arises in defining connections, principal fiber bundles, etc. But, as in the writings of Arnold or Postnikov, matrix groups (and their homogeneous spaces) are very concrete and give examples which can be worked out explicitly. Another example is that of spin structure and the Dirac operator on a manifold. As far as projective representations are concerned, the first main application concerns projective unitary representations of locally compact Abelian groups (Segal, Shale, Weil's 1964 Acta paper). When the group is Rⁿ this is the usual setting of quantum mechanics, the harmonic oscillator, etc, but equally well it could be a group of adeles. So change of fields occurs in the group being represented, not in the projective unitary group. Mathsci (talk) 14:52, 11 July 2013 (UTC)

I do not understand in this eloquence whether do you think that Spin(n) is a real-only construct, or… it ought to become so for the Sake of Accessibility? Incnis Mrsi (talk) 14:41, 11 July 2013 (UTC)

What "eloquence"? The standard method of constructing the spin group and spin representations is to define them using the real Clifford algebra of an even-dimensional real inner product space. Given an underlying complex structure on that space, there is a canonical irreducible module on which the Clifford algebra acts faithfully (the exterior algebra of the complex inner product space). The complexification can therefore be identified with the algebra of all endomorphisms of that module and the spin group with (the identity component of) the group of orthogonal operators in the real Clifford algebra that normalize the Clifford multiplication operators. The algebra and module are Z₂-graded and the Spin group acts irreducibly on the even and odd parts of the module. The action by conjugation on the Clifford multiplication operators gives a homomorphism onto the special orthogonal group. That is just the double cover by the spin group. The group Spin_c also appears in a similar way in the complexified Clifford algebra. This is all standard stuff that is used as algebraic background for the Atiyah-Singer index theorem for example. Of course Clifford algebras can be defined more generally, but there is no comparable application in topology, geometry or representation theory. Over a general field, even in characteristic zero, there is the problem of defining the Lie algebra: that is dealt with in treatments of algebraic groups, Chevalley bases, divided powers, etc, and is more involved. It is an adaptation/rephrasing/generalization of the theory over the real and complex numbers. Mathsci (talk) 08:47, 12 July 2013 (UTC)

Well, Spin(n) is certainly not a real-only construct—quite the contrary—and nor should it become so for the sake of accessibility. Indeed, the complex spin groups are actually easier to understand than the real analogs, and should not be overlooked. I agreed with the contention that it should be made clear which field(s) are involved at which times in the article spin group. But I have consistently objected to the view that our articles should always assume the maximally general point of view from the outset, which is what the OP seems to believe (in this and other threads). This has as much to do with accessibility as it does to other concerns such as WP:WEIGHT. Sławomir Biały (talk) 15:30, 11 July 2013 (UTC)

Leave the maximal generality to Bourbaki. :-) Boris Tsirelson (talk) 16:24, 11 July 2013 (UTC)

Not really my suggestion. I do think Bourbaki's style in incompatible with Wikipedia, but I don't think that they dwell excessively on generality (by modern standards). For the purposes of the present thread, I think Grothendieck's relative perspective goes way too far in that direction though. Sławomir Biały (talk) 18:05, 11 July 2013 (UTC)

For Lie groups, chapter IX of Bourbaki and Vol V of Dieudonné's treatise on analysis are just on compact Lie groups, their complexifications and real forms. They are not very different for fairly obvious reasons. Both are useful sources (sometimes even just the exercises). And yes, the structure of the complexified Clifford algebra is easier than that of the real Clifford algebra. But people who write articles are supposed to know that (or at least I would hope so). Mathsci (talk) 20:59, 11 July 2013 (UTC)

LoL. I am not an ignorant person and know (or at least heard) about these adventures more than Ozob expects. No sane person can assert that Analysis does not depend on the field. “You cannot even expect the same behavior from R and C” is an obvious strawman argument which leads to nothing. It is me who inserted “the mention of specific fields” numerous times (including quite recent navbox and linked articles), and it would be bizarre to expect that somebody here insists on “banishing” it. Incnis Mrsi (talk) 14:41, 11 July 2013 (UTC)

Then, to be entirely honest, I have no idea what this discussion is about. If there are articles that are unclear about their use of the real numbers, then they should be clarified. If there are articles that omit interesting material about fields other than the real numbers, then they should be expanded. What more is there to say? Ozob (talk) 02:22, 12 July 2013 (UTC)

If you still have no idea what an active discussion with numerous participants is about, then I can suppose an acute enumeration syndrome on your side. A Wikipedian prone to this syndrome writes article like: of trees, there are pine trees, birch trees, oak trees, … instead of describing the trunk, branches, leaves, and root. Until you become able to understand that, for example, a vector space is not “a real vector space OR a complex vector space OR a vector space over rationals OR a vector space over a finite field OR a vector space over a non-Archimedean field OR …”, you should abstain from sarcastic comments in such discussions at all. Incnis Mrsi (talk) 04:46, 12 July 2013 (UTC)

I am going to sit out the rest of this discussion, since it appears to be unrelated to writing an encyclopedia. Ozob (talk) 13:50, 12 July 2013 (UTC)

These comments bear no relation to how mathematics articles are written on WP. Teichmüller theory for example is described in the complex case. There is also a p-adic version, but I don't think it's mentioned anywhere on wikipedia, even in Schottky group. Mathsci (talk) 05:32, 12 July 2013 (UTC)

Really don’t you think so? Even after reading hatnotes?

I agree that Ozob’s comments have little to do with how mathematical articles are written on WP. But Wikipedians affected by the enumeration syndrome are not a rare phenomenon. Many articles on computing and chemistry, for examples, are rather clueless in their explanations and verbose in enumerations. Incnis Mrsi (talk) 06:03, 12 July 2013 (UTC)

@User:Incnis Mrsi: Could you be a bit more specific on how one would go about staying away from the "enumeration syndrome" in the case of Spin(n), for example? I added a brief clarification in the lede that we are using the real group SO(n)=SO(n,R). Does that solve the problem, or do you envision a different approach to Spin(n)? It is not entirely clear to me how one would go about correcting a possible "systemic bias in favor of R" in this case. Tkuvho (talk) 07:33, 12 July 2013 (UTC)

How is SL related to the case? BTW, note that Sławomir thinks that Spin is not a #real-only object. So, at least complexifications should be explicated in the article. Incnis Mrsi (talk) 08:10, 12 July 2013 (UTC)

I corrected it. Tkuvho (talk) 08:11, 12 July 2013 (UTC)

I doubt it anybody would object if a section is added to Spin(n) to cover the complex case. I must admit I am not too familiar with this case. Is this a double cover of SO(n,C)? Perhaps the problem could be solved by linking to that page. Tkuvho (talk) 08:14, 12 July 2013 (UTC)

Yes, it is. IMHO for any field Spin doubly covers SO, even for fields with discrete topology, although I am not too familiar with this case. Incnis Mrsi (talk) 09:20, 12 July 2013 (UTC)

As User:Mathsci's edit just reminded me, there is the important case of the group Spin^c, particularly useful in 4-manifold theory since such a bundle always exists in this case, providing the framework for Seiberg-Witten theory. This should certainly be mentioned at the spin(n) page. Tkuvho (talk) 08:56, 12 July 2013 (UTC)

If I remember correctly, Spin^c is a structure on vector bundles that involves recently mentioned projective reps, not a specific Lie group. It possibly would be more topical in Spinor or other articles about spinor geometry, not in article about the group. Does orientation (vector space) belong to general linear group or so, indeed? Incnis Mrsi (talk) 09:20, 12 July 2013 (UTC)

You do not remember correctly. Spin_c is the group of unitaries in the complexified Clifford algebra normalizing the Clifford multiplication operators. It is a central extension of the special orthogonal group by U(1) = T. In terms of the Spin group it is the quotient of Spin × U(1) by the diagonal copy of Z₂. It is also the canonical central extension of the special orthogonal group by T obtained by pulling back the central extension of the projective unitary group of the spin module. All this is very standard. Mathsci (talk) 14:01, 13 July 2013 (UTC)

I added some material on this at Spin_group#Complex_case. Help in formatting this properly would be appreciated. Tkuvho (talk) 09:10, 12 July 2013 (UTC)

The articles Symplectic group, Orthogonal group, and Special linear group all consider them as groups defined over arbitrary fields. It stands to reason that the same should be done in Spin group. In fact, the division presented in Symplectic group seems relevant here, due to the differing perspectives on the Spin groups, as Lie groups over R or C, or as linear algebraic groups over F. Also, note that there is some overlap with the article Spinor. Mark M (talk) 09:21, 12 July 2013 (UTC)

Articles should be developed so the first few sections are accessible to someone who is new to the area. IF a particular topic is normally only mentioned in connection with the reals in introductory texts then that is the level to aim for. The more general case can go further down the article. The lead should mention the more complex bit at the end, but should also be mainly aimed at beginners. We are not in the business of writing articles that are only readable by people who already know everything about the topic. The target audience for the first few sections should determine how they are written not the perfectitude of the exposition. Dmcq (talk) 09:32, 12 July 2013 (UTC)

Somebody should add the standard downloadable reference, "Algebraic theory of spinors and Clifford algebras" by Claude Chevalley (Collected Works, Vol 2). A short accessible description of the construction of Spin can be extracted in the real and complex case (see the summary above) and added to the article. That would cover the main applications in geometry, including Spin and Spin_c. Then in a section at the end of the article entitled perhaps "Spin groups for arbitrary fields," a brief summary of the material on that topic in Chevalley's book could be given (perhaps assuming for simplicity that the characteristic is not 2). Possibly some material on the Witt group and quadratic forms might be necessary (cf Shimura's book, Arithmetic of quadratic forms). Mathsci (talk) 10:10, 12 July 2013 (UTC)

The article Orthogonal group is an example of the imbecility of giving the generalization to general fields before the usual case, for a notion that was primarily defined only over the reals. It follows from the first sentence of this article that there are several groups O(n,R) and that the Lorentz and symplectic groups are orthogonal groups. In fact, it is not said that the matrix of the quadratic or bilinear form should be the identity matrix on some bases. It is not even said that the bilinear form must be non degenerated. D.Lazard (talk) 10:31, 13 July 2013 (UTC)

If an imbecility is demonstrated here, then it is an assertion that a symplectic group can be derived from a quadratic or a symmetric bilinear form. Omission of non-degeneracy is actually a gaffe in the article; it is the only valid point in Lazard’s posting. The question with Lorentz group is explained in the lead after several paragraphs: search for the word “definite”. Incnis Mrsi (talk) 11:11, 13 July 2013 (UTC)

The orthogonal group of a quadratic form can be defined whether or not the form is non-degenerate. This is explicitly done on page 13 of Lam Introduction to quadratic forms over fields (2005), pages 7-8 of Knus Quadratic and Hermitian forms over rings (1991) or page 19 of Cassels Rational quadratic forms (1978). It seems unlikely that all of these otherwise reliable sources would have made the same "gaffe". Spectral sequence (talk) 11:25, 13 July 2013 (UTC)

Then, there are no valid points. Incnis Mrsi (talk) 11:34, 13 July 2013 (UTC)

In response to D.Lazard's comment, I reworded the opening paragraph of Orthogonal group to emphasize the real case, but also keep the standard generalization to arbitrary fields. Is the opening paragraph now reduced in its "imbicility" levels? Mark M (talk) 11:57, 17 July 2013 (UTC)

Merge Duodecimal and Base-13

Duodecimal and Base 13 should be merged and a new page accurately describing a true base-12 number system should be created. While it may be that the system has been historically labeled as "duodecimal", the article technically describes a base-13 number system, not base-12. A discussion on the merger has been created on its talk page.
David Lones (talk) 23:34, 17 July 2013 (UTC)

There is no problem with the article. David Lones was misinterpreting the content of Duodecimal, i.e. base twelve. JRSpriggs (talk) 03:42, 18 July 2013 (UTC)

Move discussion (single digits)

See Talk:1 (number)#Requested move for a discussion that you may be interested in. -- 76.65.128.222 (talk) 05:52, 18 July 2013 (UTC)

Substitutions (a mess)

I moved Weierstrass substitution to Tangent half-angle substitution because

• It was introduced by Euler, who died before Weierstrass was born;
• The only moderately authoritative source I know of that calls it the Weierstass substitution is Stewart's calculus textbook;
• Fred Rickey, a mathematicians who has searched through Weierstrass' writings for any mention of this substitution, says it's not there.

Then in the course of fixing links to that page, I found this mess:

• We have one page called Substitution (algebra), which is about plugging in particular values in an expression. I question the idea that that's what the title "Substitution (algebra) should be about.
• We have another page called Substitution of variables, for which an appropriate title might be "Substitution (algebra)".
• We have yet another page called Plugging in. This is on the same topic as Substitution (algebra).
• We have a disambiguation page titled Substitution, and we had a redirect titled Substitutions that pointed, NOT at Substitution, but at Substitute, another disambiguation page. I've redirected it to Substitution, and put hatnotes atop both disambiguation pages informing the reader of the other page's existence.

Sigh.

Now we have a mess to clean up.

I think we ought to

• move Substitution of variables to Substitution (algebra);
• redirect Plugging in and Substitution of variables;
• fix the links to those pages.

Michael Hardy (talk) 16:47, 13 July 2013 (UTC)

Bravo for great detective work on the so-called Weierstrass substitution. Tkuvho (talk) 08:36, 19 July 2013 (UTC)

First variation

First variation could use some additional motivation. Tkuvho (talk) 08:35, 19 July 2013 (UTC)

Request for help from AfC

Please help review Wikipedia talk:Articles for creation/KSSOLV - the main issue is whether this software "toolbox" is notable or not. Thanks Roger (Dodger67) (talk) 10:36, 19 July 2013 (UTC)

Mathematics Library (IA collection) ‎

Is Mathematics Library (IA collection) a notable web resource? I don't see any significant coverage in reliable sources that are independent of the subject, but a group of editors, apparently with no interest other than this resource and its creator Hamid Naderi Yeganeh, seems to disagree. Spectral sequence (talk) 19:05, 19 July 2013 (UTC)

Now at Wikipedia:Articles for deletion/Mathematics Library (IA collection). Spectral sequence (talk) 07:51, 21 July 2013 (UTC)

There is also a Wikipedia article on Hamid Naderi Yeganeh which suffers from notability concerns as well. I have nominated that article for deletion as well: Wikipedia:Articles for deletion/Hamid Naderi Yeganeh. Moreover, I have noticed that a number of mathematics articles have had links to these self-published items in the collection linked. This seems to be spam, since it is a pretty obvious attempt by Yeganeh to have his name appear in print. Affected articles are: Liouville function, Mertens function, Prime factor, Powerful number, Divisor function, Table of prime factors, Möbius function, Euler's totient function, Table of divisors. My sense is that in many cases the links are redundant with others to more reliable sources like the OEIS. Sławomir Biały (talk) 08:56, 21 July 2013 (UTC)

Wikipedia:About Valid Routine Calculations

Members of this WikiProject may be interested in the new essay Wikipedia:About Valid Routine Calculations. I think the author would probably value input and suggestions. Yaris678 (talk) 17:11, 22 July 2013 (UTC)

That essay has some issues, and I don't think it in any way accurately reflects the many discussions that WP:CALC has been subject to. For instance, it is typically not valid to do units conversion without preserving significant digits. The example in the essay is a source that says "5300 meters" with the conversion to "17,388 ft" (while it arguably should be "17,000 ft"). Also, averaging data is not always appropriate when the data is drawn from different sources (there was a discussion about this somewhere), since different data collection methodologies make taking an average a novel synthesis. These are just the things that jump out at me. Sławomir Biały (talk) 10:18, 25 July 2013 (UTC)

KSSOLV: The AfD needs additional input

Dear mathematicians: Here is a new mathematics article: KSSOLV. I am concerned that three of the five sources are closely connected with the subject, and I don't know enough about the subject to tell if it is properly sourced or not. It certainly isn't of any use to an average Wikipedia reader, and I wonder if it contains detail that should have been saved for a journal article. Can someone check it out? Thanks. —Anne Delong (talk) 20:23, 24 July 2013 (UTC)

I see it was deleted under WP:CSD#G11. I don't think I agree that it was a speedy deletion candidate, although I probably would have voted weakly to delete it on the grounds of marginal notability at an AfD. Sławomir Biały (talk) 10:09, 25 July 2013 (UTC)

The page stated clearly that the software was unveiled 10 days ago. How much notability can it have garnered since? Tkuvho (talk) 14:21, 25 July 2013 (UTC)

It was unveiled in 2009, and announced in the ACM Transactions on Mathematical Software [4]. But that paper only has a handful of citations, hence "marginal notability". Sławomir Biały (talk) 15:03, 25 July 2013 (UTC)

This article has been created in main space and is now up for deletion discussion at Wikipedia:Articles for deletion/KSSOLV --Mark viking (talk) 23:26, 27 July 2013 (UTC)

Centered polyhedral number

Comments at Talk:Centered polyhedral number on whether this is an appropriate article title would be welcome. Spectral sequence (talk) 15:20, 28 July 2013 (UTC)

Extension:Math/Roadmap

There has been a discussion reciently on wikitech-l about the "Long term strategy for math on wikipedia", and there is an mw:Extension:Math/Roadmap document. Its all to do with MathJax, MathML various rendering methods and probably maths support in the visual editor. Theres a Google Summer of Code person working on the later so there should hopefully be some support for maths in VE soon.--Salix (talk): 17:05, 25 July 2013 (UTC)

The meta:Extension:Math/Roadmap link goes to a nonexistent page and I was unsuccessful in searching for the correct page. Is this the correct link? Thanks, --Mark viking (talk) 17:20, 25 July 2013 (UTC)

Sorry, wrong interwiki. The GSoC page is mw:User:Jiabao wu/GSoC 2013 Application a very early VE demo is mw:VisualEditor:TestMath very far from final product. --Salix (talk): 17:28, 25 July 2013 (UTC)

Salix, could you point me to some postings that explain what all this can change for readers? When will the end of (currently the default) retarded PNG renderer come in sight? Incnis Mrsi (talk) 18:36, 25 July 2013 (UTC)

I really don't know, it looks like there just tossing ideas about at the moment. The mailing list is more interesting than the roadmap. One chap has proposed a way of making MathJax available for all readers even anons. There is another idea for a faster way of rendering using HTML5 canvas. Unlikely texvc will die completely as its stable and compatible with even ancient browsers. Speed, download size, browser support and fonts are the big downsides for MathJax. Some are keen on MathML but I've been waiting 10 years for browsers support so I have my doubts on that. It might be good to put the case of better maths rendering from the maths community.--Salix (talk): 19:42, 25 July 2013 (UTC)

Is there any clear statement about whether, when and how mathematics editing will be supported under VE for articles and under Flow for talk pages? I'm getting rather disturbed by the lack of any credible commitment on the part of WMF to supporting mathematics for readers and editors. Perhaps we as mathematics editors should be thinking of taking our work elsewhere? Spectral sequence (talk) 17:03, 26 July 2013 (UTC)

I think the plan is to develop the math plugin for VE during the GSoC, when thats done we'll at least have an ability to enter the latex code, there may be live preview of the formula as you type, there may also be some form of editing visual editing of formula. When it works with VE it will work with Flow.--Salix (talk): 08:13, 27 July 2013 (UTC)

Thanks for that, but without being rude, is that anything other than a personal prediction? In other words, are you speaking for WMF, or do you know of an "official" plan or public commitment anywhere that we can refer to? Spectral sequence (talk) 11:52, 27 July 2013 (UTC)

I thought I would stick my head over the parapet to say what message I personally am getting from the whole VE thing at User_talk:Jimbo Wales#One mathematician's view of VE. Spectral sequence (talk) 21:27, 27 July 2013 (UTC)

Can I just say: if possible, it's better not to take the matter too personally. (actually this applies every time, everywhere.) Math articles/editors are not really the focus of WMF: they want more female editors and stuff from museums and aren't too interested in redoing Bourbaki and beyond! It's much better to keep making small improvements, than thinking of collective bargaining. -- Taku (talk) 22:15, 27 July 2013 (UTC)

I was unsure whether I was going to be able to make any kind of contribution, small or otherwise. It seems, thanks to Salix and Sławomir for finding out, that it will still be possible. But it seemed it might be helpful to flag up that, whatever message the WMF think they are trying to send, this is the message that is coming through to me personally: that message is they do not care about people like me, as you also suggest. And that seems an odd message to send to a volunteer contributor. Spectral sequence (talk) 06:31, 28 July 2013 (UTC)

(unindented) The message is clear: I've been (we've been) waiting SO long for better math support like commutative diagrams. (can anyone just install a package?) And what we get is VE, which is, you know, basically stupid as far as math content are concerned: a reader find an error in a formula, but he will not be able to fix the error himself! Maybe I got so used to indifference and disinterest from the "management" side that it doesn't cause me much grief. Anyway, my point still stands: from 100 years from now, Wikipedia may not exist, WMF may not exist, but I do believe the content being created and maintained here every day will remain in a certain form thanks to the free license (cc-by-sa). So, our focus should be on the content not on the management people. -- Taku (talk) 22:15, 28 July 2013 (UTC)

Just to add more griping to yours, the avowed purpose of WP:VE is to encourage more people to edit Wikipedia, people for whom the oh-so-difficult syntax of editing Wiki source is an obstruction, since there has been a problem of retaining new editors. But the reasons most editors leave have nothing to do with the editing syntax, but (in my experience) with social aspects of Wikipedia—and WP:VE perversely even acknowledges this. Visual Editor is a technical solution for the wrong problem. I predict that, contrary to the aims of the WMF, it will not encourage more quality editors to stay with the project. Instead it will result in a net negative effect: a greater share of the contributions to the project will be poor, incoherent, or outright vandalism. But this is consistent with the purpose of VE which seems to be to encourage more edits from the lazy and incompetent. Sławomir Biały (talk) 23:09, 28 July 2013 (UTC)

Readers of this thread may like to read the message from User:Jimbo Wales here in which he makes the unabmiguous commitment that The source editor will remain available so nothing about mathematical editing needs to change at all. Spectral sequence (talk) 16:37, 29 July 2013 (UTC)

Requested move: Medial

The page Medial describes medial magma or medial groupoid in abstract algebra. However, most of the pages linking there seem to intend Lateral and medial in anatomy, not any concept in mathematics. Therefore, I have requested that the page be renamed. Please see Talk:Medial#Requested move. Cnilep (talk) 02:16, 30 July 2013 (UTC)

Incoherent section in Permutation matrix

Since 4 November 2006 incoherent section Permutation matrix#Solving for P was not removed in spite of note in Talk page! It is very interesting nonsense: if this solving method is correct, then some open problems may be solved very quickly, for example, graph isomorphism problem.--Tim32 (talk) 13:38, 28 July 2013 (UTC)

I wouldn't say it's incoherent, but it's not very explicit about the hypothesis that A (and so also B) must have distinct eigenvalues. Sławomir Biały (talk) 13:53, 28 July 2013 (UTC)

"No strong opinion on whether this section belongs on Wikipedia, but I think maybe no" (History page). Yes, this section looks like WP:OR. Any reference is necessary.--Tim32 (talk) 08:58, 29 July 2013 (UTC)

Just to reinforce the message of my edit summary, I wouldn't object to the removal of the section entirely. Even if it can be sourced, it's clearly placing undue weight on a fairly routine observation. It might be worth a single sentence mention, but probably no more than that. Sławomir Biały (talk)

I deleted the section. I'm finding it very difficult to come up with an application for this. -- Jitse Niesen (talk) 09:32, 30 July 2013 (UTC)

Categorizing three requested mathematics articles

I would like to add the three redlinks in Lists of unsolved problems in mathematics (namely Taniyama's problems, Unsolved Problems on Mathematics for the 21st Century and DARPA's math challenges) to Wikipedia:Requested articles/Mathematics, but I am unsure under which heading I should place them. (Yes, there is the section Uncategorized, but I would like to place them in a more appropriate section). Any suggestions? -- Toshio Yamaguchi 14:48, 29 July 2013 (UTC)

Added. -- Toshio Yamaguchi 11:48, 31 July 2013 (UTC)

Retiring

Thanks for your good works. Kiefer.Wolfowitz 15:10, 31 July 2013 (UTC)