Wikipedia talk:WikiProject Mathematics

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Request for un-doing an old merge[edit]

I'd like to undo a merge that was done some time ago of the page Teichmüller modular group into the page mapping class group. The former is a special case of the latter but it is of enough interest to deserve its own page (in fact, in geometric group theory the name "mapping class group" is reserved by default to that of a surface). An informative analogy is to compare the situation to the similar one between braid groups and Artin groups.

One of the reasons advanced for the merger was that "In fact, Teichmueller modular group is not heard among experts as mapping class group", which is a bit dubious (typing this term in Google yields enough results, and this is definitely a terminology I've heard people in the subject use, though not as frequently as "mapping class group"), but a better name for the page might be "Mapping class group of a surface".

I'm mostly asking this because I've been revising the page on Teichmüller space and created a page on the curve complex and both topics are heavily related to the mapping class group, so I'd like to have a decent page on the latter. jraimbau (talk) 10:02, 8 July 2016 (UTC)

Since nobody objected I have written a new page, Mapping class group of a surface. It has some overlap with Mapping class group (inevitable and not a problem in my opinion). I also changed some redirects from pages that linked to the later; one remaining is Torelli group for which the content is similar on both (perhaps a bit clearer on the older page); since this topic deserves in my opinion to have its own page someday I am fine with that for the moment. jraimbau (talk) 17:07, 19 July 2016 (UTC)

Parabolic partial differential equation[edit]

Does the article Parabolic partial differential equation look like it is complete? If not could someone make some notes on its talk page about what it needs? (Thre is actually a comment there about it needing something but doesn't say what and is from 2007.) Thank you. RJFJR (talk) 01:46, 13 July 2016 (UTC)

New method to traverse binary trees?[edit]

Did I encounter a new way to traverse binary trees or is this method mentioned on some existing page? Jidanni (talk) 15:54, 15 July 2016 (UTC)

This page is primarily intended for discussion of the creation and maintenance of Wikipedia's mathematics articles. You could ask about this at Wikipedia:Reference desk/Mathematics. Michael Hardy (talk) 14:14, 16 July 2016 (UTC)

Article Möbius energy[edit]

There seems to be an important thing missing in this mathematics article. I invite to please see Talk:Möbius energy. Mr. Barris (talk) 17:34, 15 July 2016 (UTC)

I just provided there a link to articles with the definition. Boris Tsirelson (talk) 19:19, 15 July 2016 (UTC)

Article: Ellipse[edit]

Could do with an additional pair of eyes the recent edits to Ellipse. See also my talk page for a discussion on it.--JohnBlackburnewordsdeeds 14:31, 16 July 2016 (UTC)

PseudoScientist seems to know his stuff. Apparently, this is his area of expertise. What sense does it make to object to a word "amazing" that did not appear in the article? His chosen word "concise" seems appropriate for describing such formula. Besides, I see his point that the formula is "surprising" as it did not appeared before 2011. He is being totally honest with fully crediting its author.2A00:1370:8128:73E:C811:B591:263B:B6C6 (talk) 15:40, 16 July 2016 (UTC)
There is a related problem with Derivation of the Cartesian form for an ellipse which is lacking any sources. --Salix alba (talk): 20:05, 16 July 2016 (UTC)
I have sent that article to AfD. Please comment there. GeoffreyT2000 (talk) 20:56, 16 July 2016 (UTC)

Strange edits from IP[edit] (talk · contribs · deleted contribs · logs · edit filter log · block user · block log) is (helpfully) tagging dead links in math articles. In the process of doing that, however, they are also (less helpfully) replacing links to sections of articles with links to redirects. For example, this edit replaces a perfectly reasonable piped link with a link to a cryptic redirect. This edit replaces unambiguous links with redirects like coordinate chart that at least have the potential for ambiguity. WP:NOTBROKEN seems to urge against going the other way, replacing redirects with direct links. I would think that this would cut both ways. Anyway, I have reverted a few of the more questionable edits, but more eyes might be warranted. Sławomir Biały (talk) 11:56, 17 July 2016 (UTC)

There are times that redirects are preferred to section links -- when there should be such an article, and when the section isn't quite right. But this is something which should be done by a human because it needs to distinguish that special case from others which make the links more cryptic. - CRGreathouse (t | c) 21:39, 17 July 2016 (UTC)
Yes, for example this edit replaced a link to characteristic equation (specifically with that title) to secular equation (an apparently rarely used synonym) and a general link to criteria for root multiplicities to something called Scree's test, which redirects to the same section, even though in the context it is not specifically Scree's test that is relevant. Sławomir Biały (talk) 21:43, 17 July 2016 (UTC)

Should the "Dirac delta function" be referred to as an "idiom"?[edit]

I have reverted this edit to Dirac delta function. There is an editor who insists on it at Talk:Dirac delta function#Can we rename it to 'Dirac delta distribution' ?. Please comment there. Sławomir Biały (talk) 11:31, 18 July 2016 (UTC)

Category:Science technology engineering and mathematics has been nominated for discussion[edit]

Category:Science technology engineering and mathematics, has been nominated for possible deletion, merging, or renaming. A discussion is taking place to see if it abides with the categorization guidelines. If you would like to participate in the discussion, you are invited to add your comments at the category's entry on the categories for discussion page. Ottawahitech (talk) 09:38, 19 July 2016 (UTC)please ping me

Pages on algebraic tori[edit]

I have recently read the page on the notion of maximal torus. This article deals only with tori in compact Lie groups. Though the case of compact Lie groups should be discussed in this context, I see no reason why the article should be restricted to it. In fact I see a few arguments in favor of the opposite stance :

  • tori in noncompact semisimple groups are used heavily in the theory of symmetric spaces ;
  • They are also important for the classification of semisimple Lie groups (which in general is more complicated than that of only compact groups, but follows similar lines);
  • the distinction between groups having compact maximal tori (such as SL2(R)) and those not having them (for example SL3(R)) is important for their representation theory.

In addition, I think the article should be significantly rewritten to include tori in semisimple algebraic groups over arbitrary fields (which are quite important for the structure theory of these groups and also for the geometry associated to them).

To sum up, I think the Lie theory sections on Wikipedia would benefit from a reorganisation of the topics related to algebraic tori. In my opinion there should be three articles on the subject:

  • Cartan subalgebra which exists and seems good enough;
  • Torus (subgroup) which does not and should include the definition of tori in the setting of algebraic groups, the definition of the split rank of semisimple algebraic groups (in particular the real rank, currently a redirect to Iwasawa decomposition which in my opinion is not its proper place);
  • Cartan subgroup which exists but might be rewritten a little, in particular including the contents of "maximal torus" (the notions are not identical but the minor differences between them should fit in a small paragraph in this article).

I'd be happy to do this re-organising myself (this might take some time) but since this would be a fairly big change for the articles in question, if anybody is interested in Lie theory and algebraic groups and likes the articles as they are I'd be happy to discuss with them other ways to incorporate what I think is needed. jraimbau (talk) 17:09, 19 July 2016 (UTC)

I agree we don't seem to have a significant discussion of a maximal torus in the context of the theory of linear algebraic groups (say, conjugacy or relation to Cartan subgroups). "Algebraic torus" is nicely written (and fairly complete) but is written from the point of view of group schemes (in fact the reference there is SGA). For example, a lot of materials (Galois stuff) become insignificant over an algebraically closed field. A simple solution is add more materials to algebraic torus, in a way of examples, say, on the group of real points. A section on "complex torus makes sense. A section on a torus action makes sense but that one would require a separate article. A significant solution is to start a separate article, but I'm not sure if that is needed (but that's just my opinion). -- Taku (talk) 21:57, 25 July 2016 (UTC)
Yes, I noticed this article since I posted this proposal and I am currently working on adding a first part dealing exclusively with tori over field and explaining quickly the links to the classification problem for algebraic groups, and to the geometry of buildings and symmetric spaces. It would be nice if someone would then rewrite the part with arbitrary base scheme to make it more readable. jraimbau (talk) 07:56, 26 July 2016 (UTC)

Edit proposal for (complex) antiderivative[edit]

A proposal appeared:

Talk:Antiderivative (complex analysis)#Edit proposal

Hope this is a right place for the message. If it isn't, feel free to move this info elsewhere. --CiaPan (talk) 20:53, 19 July 2016 (UTC)

Content (measure theory)[edit]

The feedback request services just notified me about a RFC at Talk:Content (measure theory) about how it relates to a pre-measure. I know nothing on the subject, so I hope someone more knowledgable than me could respond. --Salix alba (talk): 06:37, 20 July 2016 (UTC)

Fresnel integral[edit]

Last night I wrote out the derivation of and . The formatting of the notation (in particular the spacing) doesn't look the prettiest and I may have missed a few details, so I'd like someone else to take a look as well.--Jasper Deng (talk) 02:59, 21 July 2016 (UTC)

Do you mean these two lines?
You may try inserting a 'narrow space' \,, for example:
Additionally you may want to replace outer parens with they \big versions:
If the over-sized fraction is what concerns you, replace it with 'tiny frac' \tfrac:
You might also want to browse Help:Displaying a formula for more options :) --CiaPan (talk) 06:44, 21 July 2016 (UTC)
@CiaPan: Thanks. It's more like my not liking how, in the longer line, the plus and minus signs have no spacing between them and the following terms, though that seems to be (on closer examination) an artifact of my using the deprecated LaTeX rendering rather than MathML. I was wondering if there was a wikiproject consensus on how I should style it, and whether there are any mathematical problems with what I wrote (I think it looks rigorous enough, though).--Jasper Deng (talk) 07:10, 21 July 2016 (UTC)

A Dedekind's theorem[edit]

The article Chinese remainder theorem has a section § Dedekind's theorem, which is about "Dedekind's Theorem on the Linear Independence of Characters". I do not know this theorem, and the section does not provide any source or link. Moreover, the given proof does not involve the Chinese remainder theorem, but its generalization to arbitrary rings, which, as far as I know, is generally not known under this name.

Thus this article is not the right place for this Dedekind's theorem. Should this section be simply deleted, or moved elsewhere (where?) D.Lazard (talk) 09:10, 22 July 2016 (UTC)

This theorem also called Dedekind's lemma and is a topic in Galois theory, e.g., Milne's field theory notes p.51, or [1]. I don't know a good target article for this material. It is used in the the normal basis theorem, so possibly Normal basis? --Mark viking (talk) 10:53, 22 July 2016 (UTC)

Set builder notation[edit]

The article Set builder notation has languished for some time in a strange state. Lately a couple users, including me, have been making efforts to improve it. Please feel free to come help bring it up to a nice state, and to make sure that the article has the right POV overall. Any references to undergraduate or graduate level books that define the notation in detail would be very welcome. — Carl (CBM · talk) 13:28, 25 July 2016 (UTC)

Sharkovskii / Sharkovsky[edit]

Our article about Sharkovskii's theorem spells Sharkovskii's name one way, but our article about Oleksandr Mykolaiovych Sharkovsky spells his name differently. I just fixed the first article so that it used only one spelling instead of two, and in the course of doing that I got very confused about which redirects where going where. It would be less confusing if we were able to adopt a single spelling throughout.

I tried to find out which spelling was preferred, but both spellings seem to be common. The original Ukrainian spelling is “Шарко́вський”. I am not sure how to proceed here. Probably doing nothing is acceptable, but I thought I would bring it up. —Mark Dominus (talk) 14:55, 25 July 2016 (UTC)

There is also disagreement about how to transliterate “Миколайович”: All of “Mikolaiovich”, “Mykolaiovich”, and “Mykolaiovych” appear. —Mark Dominus (talk) 14:56, 25 July 2016 (UTC)

Some people spell the name beginning with an ‘S’ instead of ‘Sh’, but I think this is clearly wrong. We should have redirects from these spellings, but should not use them in articles. —Mark Dominus (talk) 15:06, 25 July 2016 (UTC)

There is a standard way (actually more than one depending on year) for transliterating Ukrainian into the Latin alphabet, and then there is how S spells his own name. Since the web page listed in our article as his home page uses the "Sharkovsky" spelling, that is what I would prefer in the article about him. As for the theorem, my impression from Google scholar is that both spellings are roughly equally prevalent, but that "Sharkovskii's theorem" is a more old-fashioned spelling and that new publications are breaking roughly 2-to-1 for "Sharkovsky's theorem". Whether that's enough to change the name is unclear to me but we should probably at least mention both spellings in the article. —David Eppstein (talk) 20:54, 25 July 2016 (UTC)
Awesome, I hadn't noticed the link to Sharkovsky's home page. That gives me a clear way forward. I will of course leave redirects in place for all alternative spellings. —Mark Dominus (talk) 14:40, 26 July 2016 (UTC)
For the record, the spelling given there ( is “Oleksandr Mykolayovych Sharkovsky”. —Mark Dominus (talk) 15:11, 26 July 2016 (UTC)
Also for the record, there is a note on the talk page, ostensibly from Sharkovsky’s son, stating that “The proper latinization of "Миколайович" is Mykolaiovych”, which conflicts with the spelling on Sharkovsky’s web page. I didn't see this until after I renamed the page. —Mark Dominus (talk) 15:29, 26 July 2016 (UTC)

Proposed deletion of Musean hypernumber[edit]

Ambox warning yellow.svg

The article Musean hypernumber has been proposed for deletion because of the following concern:

Multiple concerns: *The content in itself seems not notable at all; in fact the sources point to either Charles Musès (who wasnt a mathematician, but, as wiki itself says, "an esoteric philosopher") or to Jens Köplinger, who seems the author of this article itself, as he says in the talk at special:diff/99213211: "In order to support notability, you were asking whether these numbers were "widely studied"? I wish they were. To me they are a widely referred-to concept that is in deep need of study. Other than Charles Musès and Kevin Carmody, I only know about myself [2] having formally published in a mathematical context. Informally but mathematical, there are references in monographs by Robert de Marrais (e.g. [3] and others) or self-maintained web pages (e.g. Tony Smith's [4]). But, most other references are outside the field of mathematics, in attempts to link consciousness with mathematical concepts, and in spiritual and religous ideas (an internet search shows all kinds of mentions, some serious; I don't want to go there).". *References to mathematics and physics terminology is all wrong and nonsensical, how is that an algebra? How such construct relates to quantum consciousness, as Musean hypernumber#Visions_of_applicability implies? It seems non-rigourous patent nonsense. *Even if this were notable, its lack of mathematical rigor and standard terminology, as well as its original creator being an "esoteric philosopher", would make the perspective from which is told this article completely wrong. If this isnt real mathematics, but rather "the view of mathematics said philosopher had" the article must state it and not trying to sell such concept as if it had the same mathematical status of real analysis.

While all constructive contributions to Wikipedia are appreciated, content or articles may be deleted for any of several reasons.

You may prevent the proposed deletion by removing the {{proposed deletion/dated}} notice, but please explain why in your edit summary or on the article's talk page.

Please consider improving the article to address the issues raised. Removing {{proposed deletion/dated}} will stop the proposed deletion process, but other deletion processes exist. In particular, the speedy deletion process can result in deletion without discussion, and articles for deletion allows discussion to reach consensus for deletion. Nickanc (talk) 13:45, 26 July 2016 (UTC)

due to a revert, it is now an AfD.--Nickanc (talk) 12:31, 27 July 2016 (UTC)

Content (measure theory) (please revert me?)[edit]

User: vastly expanded Content (measure theory). User:Kusma reverted that edit citing where it was incorrect. User:Mark viking seemed to further explain the problems with's edit in talk. A week later's sock-puppet account reverted it all back again. I have reverted that last edit since it wasn't kosher re: fabricating support for an edit via sock-puppetry and putting on a charade of being someone else. I have no idea if its a valid good-faith edit mathematically speaking, somebody in this project should probably look it all over. Fountains of Bryn Mawr (talk) 14:49, 27 July 2016 (UTC)

In the meantime the IP has been blocked for 3 months and Gagz7 has been indefinitely blocked for socking. —David Eppstein (talk) 16:08, 27 July 2016 (UTC)

A Categories for deletion discussion WikiProject members may be interested in.[edit]

It concerns the categorizing of Mathematicians by city. The discussion can be found here[5]....William, is the complaint department really on the roof? 21:08, 27 July 2016 (UTC)


I thought that maybe the articles Tacito Augusto Farias and Douglas Smigly should be deleted for lack of notability. The second one is just 18 years old undergraduate student and the user who created it here also seems to be doing cross-wiki mass creation... TunksunT (talk) 23:43, 27 July 2016 (UTC)

XfD discussion[edit]

There is a discussion on whether to delete Draft:Basic theorems of algebraic K-theory at Wikipedia:Miscellany for deletion/Draft:Basic theorems of algebraic K-theory. Ozob (talk) 01:00, 28 July 2016 (UTC)

Rassias' conjecture[edit]

An article Rassias' conjecture was created some time ago, possibly by Rassias himself, as something of a promotional piece. It has been carefully sourced and I feel that is does meet WP:GNG and so I have been editing it recently to improve its quality. Some fresh eyes would probably help improve the article further.

CRGreathouse (t | c) 04:03, 29 July 2016 (UTC)

Almost integer[edit]

In the example at the top of the almost integer article, there is a formula which appears truncated to me. <math>\frac{1}{2}\sqrt{\frac{1}{30}(61421-23\sqrt{5831385})} </math> appears to me with the integer 58313 instead of 5831385 under the square root - in other words, the expression is truncated. Any idea why this is or how to fix it? The illustration of the golden rectangle near the top of the golden ratio article also has a truncated formula. EdChem (talk) 10:13, 29 July 2016 (UTC)

I see the whole integer (in the image thumb), and also no issue in golden ratio. What browser/OS are you using and what is your math preference set to? --Izno (talk) 11:41, 29 July 2016 (UTC)
I'm using Edge in Win 10. If I open in IE 11, the full formulae show. No idea where math preferences set up is. Thanks. EdChem (talk) 12:18, 29 July 2016 (UTC)

Draft:Quasi-abelian category[edit]

Anyone want to take a crack as to whether this Draft should be moved to mainspace?Naraht (talk) 18:06, 29 July 2016 (UTC)

The topic looks notable; a search produces multiple RS. This looks like a solid start-class article, with the basics of the definition, examples, and good references. --Mark viking (talk) 18:15, 29 July 2016 (UTC)
I have now accepted this AfC draft and moved it to mainspace. GeoffreyT2000 (talk) 18:22, 29 July 2016 (UTC)