Wikipedia talk:WikiProject Mathematics

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
Nuvola apps edu mathematics-p.svg
This is a discussion page for
WikiProject Mathematics
This page is devoted to discussions of issues relating to mathematics articles on Wikipedia. Related discussion pages include:
Please add new topics at the bottom of the page and sign your posts.
Frequently asked questions (FAQ)
Information.svg To view an explanation to the answer, click on the [show] link to the right of the question.

          A Wikipedia ad has been created for this project page

List of all archives

2009: Jan · Feb · Mar · Apr · May · Jun · Jul · Aug · Sep · Oct · Nov · Dec
2010: Jan · Feb · Mar · Apr · May · Jun · Jul · Aug · Sep · Oct · Nov · Dec
2011: Jan · Feb · Mar · Apr · May · Jun · Jul · Aug · Sep · Oct · Nov · Dec
2012: Jan · Feb · Mar · Apr · May · Jun · Jul · Aug · Sep · Oct · Nov · Dec
2013: Jan · Feb · Mar · Apr · May · Jun · Jul · Aug · Sep · Oct · Nov · Dec
2014: Jan · Feb · Mar · Apr · May · Jun · Jul · Aug · Sep · Oct · Nov · Dec
2015: Jan · Feb · Mar · Apr · May · Jun · Jul · Aug · Sep · Oct · Nov · Dec
2016: Jan · Feb · Mar · Apr · May · Jun · Jul · Aug · Sep · Oct · Nov · Dec
2017: Jan · Feb · Mar · Apr · May · Jun · Jul · Aug · Sep · Oct · Nov · Dec
2018: Jan · Feb · Mar · Apr · May · Jun · Jul · Aug · Sep · Oct · Nov · Dec

Disambiguation links

Hi, could anyone here help fix a few links to disambiguation pages?

Bolza surface has a link to Perturbation, Finsler manifold has a link to Minkowski norm and Simplicially enriched category has a link to Simplicial category.

I don't know whether there is a good target article for the links in question, or whether the link should be removed, as my level of Mathematics is not advanced enough to understand these topics. Thanks for your help. IffyChat -- 12:20, 31 July 2018 (UTC)

"Bolza surface" and "Finsler manifold" now fixed, but "Simplicially enriched category" is not. Boris Tsirelson (talk) 14:27, 31 July 2018 (UTC)
I "fixed" the last one by just removing that section; it was in pretty bad shape – bad English, questionable math, broken refs, etc. –Deacon Vorbis (carbon • videos) 15:29, 31 July 2018 (UTC)

Vital articles

Is it just me, or are a lot of articles getting promoted to "vital"? I don't normally pay attention to that sort of meta classification, but SSTbot (talk · contribs · deleted contribs · logs · edit filter log · block user · block log) has been promoting lots of articles that I wouldn't have thought should be considered "vital". For example, Bessel function is rated as "mid" importance by WikiProject Mathematics. Should it be only mid importance, but also vital? (Note: I have no strong opinions about any of this. I'm just noting that something doesn't quite jibe about it.) Sławomir Biały (talk) 20:45, 1 August 2018 (UTC)

As far as I know, the SSTbot is promoting articles in Wikipedia:Vital_articles/Level/5/Mathematics; for instance Bessel function is listed at Wikipedia:Vital_articles/Level/5/Mathematics#Calculus_(32_articles). I, too, don't have much of an opinion on what is included, but that is probably the place to discuss. --{{u|Mark viking}} {Talk} 20:54, 1 August 2018 (UTC)
Quantum cohomology is a more egregious example than Bessel function (and I'm even a fan of the former). I don't understand the procedure by which Wikipedia:Vital articles/Level/5/Mathematics is populated. Mgnbar (talk) 21:10, 1 August 2018 (UTC)
I would recommend mostly ignoring VA in general. I'm an occasional participant in level-3 discussions, but largely against my better judgment. I don't really see the point of the whole thing. It seems to be mostly a place to argue about why what's important to me is more important than what's important to you. --Trovatore (talk) 21:28, 1 August 2018 (UTC)
Level 5 is a recent expansion to vital articles. Right now it's basically a WP:BOLD wildwest. Once it's got its critical mass of articles, I suspect there'll be an actual process in place. If anything egregious is missing, add it, if something completely silly is added, remove it. Headbomb {t · c · p · b} 23:55, 1 August 2018 (UTC)

Yeah, a bot for tagging these articles ran today. The current "quota" is 1200 articles (total) at level-5, including 300 at level-4 (biographies excluded from that count). My mental threshold is whether the topic would be discussed in a book-length mathematics encyclopedia. That's probably anything at "mid" priority or higher; Bessel function is One of the 500 most frequently viewed mathematics articles. and is probably important enough to be listed (no opinion on Quantum cohomology). power~enwiki (π, ν) 01:53, 2 August 2018 (UTC)

If anything of "mid" importance is "vital", then we have a serious terminology mismatch. (This is not an attack on you, though. :) Mgnbar (talk) 11:43, 2 August 2018 (UTC)
Maybe a better terminology would be "vital indeed" for level 1, "vital" for level 2, "half-vital" for level 3, "not quite vital" for level 4, and "not vital at all" for level 5?   :-)   Boris Tsirelson (talk) 11:16, 3 August 2018 (UTC)
My issue is not with the article Bessel function per se. But many of the other articles being promoted to vital in SSTbot (talk · contribs · deleted contribs · logs · edit filter log · block user · block log) strike me as borderline at best. I realize a case could be made that articles like Methods of detecting exoplanets or Planetary differentiation, for example, are vital articles. But, on the other hand, something doesn't quite jibe about many of the articles I see getting promoted. Many are, for lack of a better word, borderline. Often they are only rated "mid" importance, for example, in their WikiProject designations. Something doesn't feel quite right if a WikiProject designates an article as "Mid" importance, but then a bot apparently upgrades it based on some list somewhere of "vital" articles. Why is there a discrepancy in the assessment? Sławomir Biały (talk) 12:07, 3 August 2018 (UTC)
If you want to suggest a different name ("Moderately vital articles") that isn't quite as silly as that suggestion, please do so. power~enwiki (π, ν) 03:16, 5 August 2018 (UTC)
These all should be clearly more vital than articles such as Maris–McGwire–Sosa pair, Square Root Day, or Hensel's lemma. power~enwiki (π, ν) 03:20, 5 August 2018 (UTC)
One of those things (Hensel's lemma) is not like the others. It actually has some mathematical significance rather than being a piece of cultural trivia. —David Eppstein (talk) 04:02, 5 August 2018 (UTC)
Yes, Hensel's lemma is vital in this apparently non-vital sense, which apparently means "something Wikipedia should have an article on". Sławomir Biały (talk) 12:02, 5 August 2018 (UTC)
I agree there's a (large) gap between "important to have an article, but not the top 1000 topics" and "crap that is too much work to get deleted". power~enwiki (π, ν) 16:16, 5 August 2018 (UTC)
I feel the best approach to vital articles is "If this were an encyclopedia on topic X, and we only have room for Y topics, would this make the cut?" When you have 5 articles to work with, it's pretty reasonable to exclude Calculus. But if you have ~50 articles to work with, then it can make the cut. I don't know if I'd include Bessel functions if I were limited at 300 topics, but certainly I'd talk about them if I had room for 1100 topics. At that level, I'd also leave out Maris–McGwire–Sosa pair, but there's room to talk about Recreational mathematics. Headbomb {t · c · p · b} 16:34, 5 August 2018 (UTC)

Newton–Cotes formulas mistake?

Hi would someone be able to check the 'Newton–Cotes formulas page; Closed Newton-Cote formulae' section, specifically the (3rd and 4th) rows of formulae in the table...

1) The Simpson's 3/8 rule & Boole's rule do not appear to be consistent with the Trapezoid rule and Simpsons rule in that where they have used (b-a), I feel like they should have used (b-a)/n where n is the degree. This appears to be what they have done for trap/simpsons rule. The linked Boole's rule wiki page itself does have the initial coefficient as 2*h/45 and I believe h := (b-a)/4, meaning that using the style implemented on the Newton Coates page, the first coefficient should be 1/90 (i.e. (2/45)/4), and similarly the 3/8th simpsons rule should start with 1/8. As a reference I'm comparing to the Introduction to Numerical Analysis Springer book by Stoer and Bulirsch who provide a table for comparative purposes.

2) In the book I've just mentioned (page 126 for the table), the names of the interpolation schemes are different too. That reference names the degree 4 scheme as Milne's rule, whereas the wiki page seems to refer to places where it is called Boole's rule, and yet it uses Milne's rule for a different formula further down. I feel like (at least personally) I'm getting confused by all the names. Is there any way to clear it up?

Thanks, — Preceding unsigned comment added by 2a0c:5bc0:40:107c:c479:58f9:bf8b:42cf (talk)

Courtesy link: Newton–Cotes_formulas#Closed_Newton–Cotes_formulas. --JBL (talk) 13:45, 3 August 2018 (UTC)
I changed the coefficients to match, but I'm not going to wade into the naming stuff. –Deacon Vorbis (carbon • videos) 13:56, 3 August 2018 (UTC)

Help with "Good Article" review of "Georg Cantor's first set theory article".

Here is the article: Georg Cantor's first set theory article

Here is the "Good Article" review page: Talk:Georg_Cantor's_first_set_theory_article/GA2

I created the page originally, but most of what's there now is the work of Robert Gray, a historian of mathematics who has published refereed scholarly articles on this topic.

Work is needed to respond to the recommendations on the review page in order for this article to be promoted. There is Robert Gray is on vacation and not aware of the current situation. Michael Hardy (talk) 15:49, 3 August 2018 (UTC)

I like the article, and I think it would be a shame if the nomination fails simply because some editor is having two weeks off. Michael, maybe you could ask the reviewer to extend the on hold for a bit longer than 7 days (which anyways are a somewhat arbitrary interval in my mind)? Jakob.scholbach (talk) 21:14, 3 August 2018 (UTC)
I still very seriously object to the name. My opinion is that articles about specific publications should be named after the publication — in this case On a Property of the Collection of All Real Algebraic Numbers.
There are several considerations that lead me to this conclusion. The most important one is that descriptions are the last choice for the titles of WP articles. For articles whose title is not a simple common noun, we should strain to use proper names and terms of art before natural-language descriptive phrases.
Secondarily but still importantly, article strikes me as a bad description for this seminal paper. TIME has articles. Wikipedia has articles. Research scientists publish papers. They may also publish articles, but the articles are less important than the papers. The articles tend to be surveys and reviews rather than original contributions. --Trovatore (talk) 21:23, 3 August 2018 (UTC)
I don't remember what this article's title was originally. I can't find it in the edit history, and I wonder if that has to do with some deletions and restorations and edit history mergers. I remember that it was changed to its current title from something else. I think it may have been something like "Cantor's first uncountability proof". Michael Hardy (talk) 17:16, 4 August 2018 (UTC)
ok, I found it. It was Cantor's first uncountability proof. I agree that the title of Cantor's paper would be better than the Wikipedia article's current title. Michael Hardy (talk) 17:19, 4 August 2018 (UTC)
I am inclined to agree with the proposal to make the title of Cantor's paper the title of this article. Here's another instance: An essay towards solving a problem in the doctrine of chances. Michael Hardy (talk) 18:15, 4 August 2018 (UTC)

comments on the review

I've put some comments here on the review page. Opinions? Michael Hardy (talk) 18:34, 4 August 2018 (UTC)

Wiki Education hiring an experienced Wikipedian

Wiki Education is hiring an experienced Wikipedian for a part-time (20 hours/week) position. The focus of this position is to help new editors (students and other academics) learn to edit Wikipedia. The main focus of the position is monitoring and tracking contributions by Wiki Education program participants, answering questions, and providing feedback. We're looking for a friendly, helpful editor who like to focus on article content, but also with a deep knowledge of policies and guidelines and the ability to explain them in simple, concise ways to new editors. They will be the third member of a team of expert Wikipedians, joining Ian (Wiki Ed) and Shalor (Wiki Ed). This is a part-time, U.S. based, remote or San Francisco based position.

We are especially interested in people with a background editing maths-related articles. See our Careers page for more information. Ian (Wiki Ed) (talk) 20:07, 6 August 2018 (UTC)

Draft:Paraconsistent mathematics needs help

The creator, Schiszm seems to be a competent academic writer and my gut says this surely should be a notable subject, but the draft needs to be substantially reworked to fit in WP, particularly in terms of the style and tone. Please advise and assist the original contributor. Thanks Roger (Dodger67) (talk) 18:20, 9 August 2018 (UTC)

Please... Roger (Dodger67) (talk) 16:22, 15 August 2018 (UTC)

What does Draft:Paralogic do that Paraconsistent logic does not already do? Should we really help with an article which talks about a "supernatural process"?
In any case, I see no value in paraconsistent logic or fuzzy logic or anything based on such illogical "logics". The purpose of logic is to make clear distinctions. If you cannot even distinguish between truth and falsehood, then what can you distinguish? JRSpriggs (talk) 20:53, 15 August 2018 (UTC)
Speaking as a complete novice, how about merging it with paraconsistent logic? I don’t think the question whether we need this type of “logic” or math based on it is relevant here; only the notability. —- Taku (talk) 21:37, 15 August 2018 (UTC)
I think the merge makes sense, but the problem still remains that someone would need to do it, and it's not clear whether we have anyone with both the competence and the desire. I do not understand the material well enough to do it, and I don't have enough desire to go acquire that competence. It's possible that someone here does, but no one has stepped forward so far. --Trovatore (talk) 22:09, 15 August 2018 (UTC)
Just want to point out the draft that needs help is Draft:Paraconsistent mathematics, and not Draft:Paralogic. Sorry I can't help with the issue, I'm just an AFC reviewer, not a topic specialist. Roger (Dodger67) (talk) 22:32, 15 August 2018 (UTC)
I do not understand the material well enough, too. But I note that most of the draft is not quite about paraconsistent mathematics. (Why discuss in detail numerous non-mathematical "definitions" of continuity in dictionaries? (Here) Mathematical definitions are conventional, explicit, sharp in all kinds of math, except maybe for recreational math, but including paraconsistent math.) Looking at the Stanford Encyclopedia of Philosophy I see more about mathematics, but still, not a lot; and often the relevant math is mentioned rather than explained. Basically, there I see the following (quoted).
  • A number of people including da Costa (1974), Brady (1971, 1989), Priest, Routley, & Norman (1989, pp. 152, 498), considered it preferable to retain the full power of the natural comprehension principle (every predicate determines a set), and tolerate a degree of inconsistency in set theory. Brady, in particular, has extended, streamlined and simplified these results on naive set theory in his book (2006); for a clear account see also Restall’s review (2007).
  • If the Russell Contradiction does not spread, then there is no obvious reason why one should not take the view that naive set theory provides an adequate foundation for mathematics, and that naive set theory is deducible from logic via the naive comprehension schema.
  • Weber, in related papers (2010), (2012), has taken the inconsistency to be a positive virtue, since it enables us to settle several questions that were left open by Cantor, namely, that the well-ordering theorem and the axiom of choice are provable, and that the Continuum Hypothesis is false (2012, 284).
  • Cantor’s Theorem continues to hold; that is, it does not depend on overly-strong logical principles which are contested by paraconsistentists.
  • Hilbert’s program was the project of rigorously formalising mathematics and proving its consistency by simple finitary/inductive procedures. It was widely held to have been seriously damaged by Gödel’s Second Incompleteness Theorem, according to which the consistency of arithmetic was unprovable within arithmetic itself. But a consequence of Meyer’s construction was that within his arithmetic R# it was demonstrable by finitary means that whatever contradictions there might happen to be, they could not adversely affect any numerical calculations. Hence Hilbert’s goal of conclusively demonstrating that mathematics is trouble-free proves largely achievable as long as inconsistency-tolerant logics are used.
  • Robinson’s (1974) non-standard analysis was based on infinitesimals, quantities smaller than any real number, as well as their reciprocals, the infinite numbers. This has an inconsistent version, which has some advantages for calculation in being able to discard higher-order infinitesimals. Interestingly, the theory of differentiation turned out to have these advantages, while the theory of integration did not.
I guess, for now this is (roughly) all the paraconsistent mathematics available. If so, then the draft should be short, accordingly, and more specific, explaining these points (in particular: which paraconsistent logic is used? several are in use), and not overlapping too much the "paraconsistent logic" article. If indeed the creator is a competent (in this matter) academic writer, he/she should be able to do it. Boris Tsirelson (talk) 17:01, 16 August 2018 (UTC)

HTML entities and Unicode characters

FYI, I'm proposing a stronger style convention for special characters which are often seen in math-related articles. The idea is to use Unicode characters like ÷ instead of HTML entities like ÷, except in cases where characters can be confusing or there's an existing guideline to do something else (like with fractions and superscripts). If you'd like to read and/or comment, the latest version is at Wikipedia talk:Manual of Style § Fourth draft. Thanks! -- Beland (talk) 06:50, 10 August 2018 (UTC)

For heaven's sake, please, prevent any activists from adding more tabulated bureaucracy to the already enriched WP:MOS (e.g.: idiosyncratic "spacing of dashes"!). All the already stated precautions do apply fully to the draft, imho. Let's not have more of "I am an expert in the guidelines, which you constantly disrupt." and "I don't care a sh*t about you toiling to restore meaning, which is against (my) guidelines."
Why is it necessary to have so much canvassed into one go? Replacing hex-codes is a fine thing to do. I do not feel sufficiently prepared to comment directly on the MOS-TP. unintended copy on the science-project site Purgy (talk) 07:39, 10 August 2018 (UTC)
To Beland: Please let us have a complete list of the unicode characters which you propose that we should use in the source. How are we supposed to generate them? Anyone can easily type in "&" followed by "divide;", but how do I make the unicode divide character? What is the point of wasting our time doing this anyway? JRSpriggs (talk) 04:01, 11 August 2018 (UTC)
@Beland: Nope. I can type characters like right arrow (→), degree (°) or times (×) with Alt+0nnn on numeric pad of my Windows keyboard — but that's virtually all. Oh, yes, I can also type a dash (—). But for most mathematical symbols (including, but not limited to floor/ceil operators, radical, divide or even pi, delta and epsilon!) I need a Character table applet to pick and copy+paste one. So it's much easier and much faster to simply type the HTML entity code and let the HTTP server + HTML client do the work for me.
Let alone (rare) editing from an Android phone, where I need additional two or three clicks to get to appropriate symbols page in a touch-screen 'keyboard' and then back to alphanumerics. To make things worse, many special symbols simply do not even exist in that keyboard and there's no such thing like Alt+0nnn on it. (Or at least I do not know how to activate it.)
No, I'm not going to waste my time on learning codes and typing them just because someone considers & code ugly. It is standard and it works, so I stick to it. --CiaPan (talk) 09:33, 17 August 2018 (UTC)

Oh hi everyone, I hadn't noticed more discussion was happening here.

  • @Purgy Purgatorio: Well, I didn't think asking a question about HTML entities in general was particularly overwhelming. We seem to have been able to brainstorm what characters are worth keeping as named entities for clarity or because opinions differ as to which is best. I don't think people should be fighting over this sort of thing; this is a pretty clear binary choice, and if there's a good reason not to convert in a particular sort of situation, that should be reflected in the guideline.
  • @JRSpriggs: There are over 137,000 defined Unicode characters for which it is possible to write a numerical code, so providing a complete list of those would not be helpful. There's a complete list of all the ones for which named HTML entities exist linked from the proposal; that list is at [1]. (Not all of those are necessarily supported in all browsers.) The general recommendation would be to use the Unicode character unless it's found on one of the two short tables in the proposal at Wikipedia talk:Manual of Style § Fourth draft. Over time we may find we want to add more exceptions, for example if there's a new whitespace character we discover a good use for, which would otherwise be invisible.
  • @JRSpriggs: and @CiaPan: If you edit any Wikipedia page, you'll see immediately below the main text entry area a way to add Unicode characters to articles. When editing from a desktop browser, there's a pull-down menu (initially it says "Insert") which gives you access to a lot of common characters. For math articles, I think most of what you're looking for (including the divide symbol) are accessible from "Math and logic" on the pulldown or "Greek". I'm sure there are more obscure characters not listed here, but obscure characters don't have named HTML entities either, so we'd be using a complicated input method in any case (a special character picker, entering Unicode number by keyboard, or copy-and-paste from another wiki or web page or local document). The mobile experience is not so nice for direct character input for mathematics, but I sometimes have to change my Android browser to desktop mode to edit Wikipedia anyway, if I'm doing certain things the mobile interface doesn't support. (Or maybe there's a widget you can activate in your preferences or that could be improved by the Mediawiki developers.)
  • Everyone: I think there are three reasons to do this:
    • Search results - for example, if you include ‰ in your search, that won't find articles that use ‰.
    • WYSIWYG editing - Seeing the actual mathematical symbol in the wikitext is just easier to read, understand, and change, even if you are familiar with the entity names. It looks more like math looks on a blackboard or printed page, and there's no possibility of accidentally breaking the markup by dropping a semicolon (which I've been correcting a lot of lately).
    • New editors - I'm impressed at how well editors who have been dealing with these things have picked up the HTML entities and keyboard codes and whatnot. For editors who are new to Wikipedia or who only occasionally deal with topics that require special characters, the vast majority don't know HTML or about HTML entities, so seeing them is confusing. If they want to enter characters that way, it's basically a secret code they need to learn and remember or write down or bookmark or something. This seems to me like a barrier to entry, and I'm afraid seeing a bunch of &s and ;s on certain articles is causing some fraction of potential contributors to just turn and run. We do at least support TeX markup with <math> for academics and folks familiar with that, so that's something. But being able to tell someone to just scroll down and use the pull-down to stick in the characters they need is a bit lower-friction.
  • I don't see any reason why experienced editors who are used to writing &divide; and whatnot shouldn't to continue to do so. In general, we're expected to welcome all contributions, whether or not they are in the preferred style. I have a program that scans the entire encyclopedia for HTML entities (among many other things) twice a month, so what I would expect to happen is that a volunteer would quietly change that &divide; to ÷ for the reasons listed above. I think that will result in easier reading and cut-and-paste work even for the editor who originally added it. For characters where both styles are accepted (like for dashes) nothing would happen. If pointers to the guideline helps inform more editors about direct character input method and they like it better or find it easier, that would both save volunteer time and be a win for editors, but no one should go around punishing people for not using the preferred system up front. In my experience this is how the style guidelines generally work, so I can leave this as an implicit thing, or I can add language to the proposal explicitly saying editors can use whatever format they're most familiar with as long as they don't mind if someone else changes it to the preferred format (if there is one) for them later? -- Beland (talk) 15:19, 17 August 2018 (UTC)
@Beland: no additional textwall will wipe out your above threat ... that a volunteer would quietly change..., and the Danaans' present "No one should go around punishing people for not using the preferred system up front." looks like shafts of satire. May I point you to my writing above: "I am an expert in the guidelines, which you constantly disrupt." and "I don't care a sh*t about you toiling to restore meaning, which is against (my) guidelines."??? Being welcome in this specific mode is bluntly deterrent. I oppose to establishing this revised WP:MOS with all my negligible might. BTW, I looked at the discussion with D. Eppstein et al., too. Purgy (talk) 14:10, 18 August 2018 (UTC)
Well, "we can't have a guideline because someone might complain that I'm violating it" is an argument against having a Manual of Style at all, which we clearly can't do. In the larger picture, style manuals reduce conflicts, because they are mostly documenting arbitrary choices made after discussion and some form of consensus. Without one we'd be having the same discussions or arguments over and over again. It sounds like you may also have had trouble in situations where there are multiple conflicting goals, and there's some disagreement over which is most important. That's a natural thing to have discussions about; without a style guide, we'd just be having the same discussions but without the benefit of having parts of those disagreements already settled. If people are condescending or mean or pushy in such discussions, that's just something we'll have to deal with as part of modern culture or as a violation of WP:CIVIL. -- Beland (talk) 16:39, 18 August 2018 (UTC)

Schröder–Bernstein theorem: OR or not?

A nice proof is added recently to "Schröder–Bernstein theorem" by KeesDoe, see here and here, and challenged by "citation needed". It is very easy to check the proof... can it survive unsourced? can it be sourced? Boris Tsirelson (talk) 10:16, 11 August 2018 (UTC)

IMO, this is a case of WP:IAR. This situation is rather frequent in mathematics, where some proofs and some results belongs to the common knowledge of the specialists, but are not sufficiently new for being the object of a publication, or were published a long time ago and cannot be retrieved by Google search. Moreover, a content is WP:OR, only if no source exists, not if no source is provided. In this case, it is unbelievable that no sources exist, although it may be difficult to find them. I have encountered the same problem many times when editing WP. Here are two examples. When editing Quartic function, I introduced a section on the nature of the roots. At that time, I did not know any source. A source in an article of 1922 has been provided later by a reader who discussed the slight difference between the two presentations. A second example, still unsourced was motivated by a discussion at Talk:Homomorphism#Inaccuracy (remainder) on the relationship between injections and surjections on a side and monomorphisms and epimorphisms on the other side. The main fact is that, in most (but not all) common cases, the two terminologies are equivalent, but I do not know a source giving explicitly a list of these cases. I have thus added collapsed proofs to Homomorphism for replacing missing sources. These proofs are certainly not new. My point of view about this example is a personal interpretation of the first paragraph of WP:Verifiability. The main point for WP is verifiability; this results normally from reliable sources, but, in mathematics, this may also result from a proof. D.Lazard (talk) 11:06, 11 August 2018 (UTC)
Rather convincing.
A kind of source: [2]. Boris Tsirelson (talk) 16:44, 11 August 2018 (UTC)
While a citation to this related result would be best, I agree with D.Lazard's point that it is difficult to source source every aside, especially if it seems routine or obvious to the experts. This could perhaps fall under the umbrella of routine derivation or common knowledge. That said, the problematic part is the language. Stating "It is easy to see that" is a challenge to the reader. This is good in a textbook where the author is a mentor encouraging readers to work it out for themselves. In WP, that sort of challenge just generates citation requests. --{{u|Mark viking}} {Talk} 18:36, 11 August 2018 (UTC)
In addition to needing an edit for math markup, the explanation could do with a little smoothing. For example, is at first the identity, but then denotes something else. XOR'easter (talk) 20:15, 11 August 2018 (UTC)
I'd agree with D.Lazard that obviously correct proofs are in doubt a case for WP:IAR. While providing reference in such cases would be better, simply deleting such correct proofs just because of missing reference is worse and disservice to readers.--Kmhkmh (talk) 20:36, 11 August 2018 (UTC)

Draft:Journal of Combinatorial Algebra

Is this a notable journal (in the sense it can belong to mainspace)? -- Taku (talk) 23:31, 13 August 2018 (UTC)

Did you read the reason the draft was declined? The only real notability guideline for journals is WP:GNG (we also have WP:NJournals but that's just an essay). GNG requires in-depth coverage of the subject in multiple reliable published sources that are independent of the subject. For instance maybe someone wrote a section about the journal in a biography of one of its founders, and published it in another journal. Do you have sources like that? If so, add them to the article, and notability should become clear. If not, it is most likely not notable. —David Eppstein (talk) 00:14, 14 August 2018 (UTC)
No I didn't and I simply asked because I'm not familiar with the notability guidelines for the journals and so I was hoping the other members of the project to take a look at it. The question was not meant to be rhetorical here. -- Taku (talk) 00:23, 14 August 2018 (UTC)
I am regularly shocked by the low standards in practice for articles about journals. Like, here is an AfD I started about an article with 0 citations, and the only two votes so far are "keep". Anyhow, I asked about this journal here a year ago, you can see the feedback I got then. --JBL (talk) 01:16, 14 August 2018 (UTC)
Stop stealth canvassing. As for this journal, merge the first paragraph to European Mathematical Society and call it a day. Headbomb {t · c · p · b} 01:33, 14 August 2018 (UTC)


An IP editor is inserting masses of what looks to me to be original research at Duodecimal and reverting without comment whenever anyone (or at least me) tries to prune it back again. More eyes on the article would be helpful. —David Eppstein (talk) 01:14, 15 August 2018 (UTC)

Wow, this article is pretty bonkers even without that (it's around 150k!). The IP in question locates to Taiwan, and they've been fairly busy. I reverted some dubious additions at Unique factorization domain from the same editor, but they've edited from a number of different addresses and have been hitting some other articles as well. –Deacon Vorbis (carbon • videos) 02:16, 15 August 2018 (UTC)

Rectangles in every day life

I just stumbled across Supergolden ratio, which attributes to the source

The Changing Shape of Geometry: Celebrating a Century of Geometry and Geometry Teaching, "4.13". Mathematical Association of America (2003). Cambridge University Press. pp. 320–326. ISBN 9780521531627.

the following paragraph, as well as a corresponding sentence in the lead:

The supergolden rectangle is common in everyday life. The ratios of the sides of rectangular household objects like Sunday newspapers and Cornflakes packets are within half of a percent of 1.46557…, the supergolden ratio. This is because the supergolden rectangle is a good balance of aesthetic (The supergolden algebraic relationship x3=x2+1 is similar to the golden algebraic relationship x2=x+1, but the supergolden geometric relationship is somewhat more complicated than the golden geometric relationship.) and practical (The supergolden rectangle's proportions are more suited for various roles than those of the golden rectangle, which is too narrow for many uses.), allowing it to become widely used in society. However, while the supergolden rectangle is the most common, other proportions are also commonly used, including 2 (paper), ρ (Weetabix box), and φ (softback book).

(A good comparison is the article golden ratio.) I do not presently have access to the complete relevant section of the source (Google books cuts off, and I am traveling) but I thought others might want to take a look. --JBL (talk) 12:28, 15 August 2018 (UTC)

The referenced source is a book chapter, but it was originally published in The Mathematical Gazette and can be read on JSTOR. The claims in supergolden ratio vastly oversell what that source actually says, when they do not contradict it; for example, Crilly says that softback books aren't even uniform in ratio. I've removed that paragraph and the corresponding lead sentence accordingly. XOR'easter (talk) 15:33, 15 August 2018 (UTC)
OK, we're now getting into a bit of back-and-forth about this. Other opinions would be much appreciated. I won't touch it again until someone else weighs in, since I don't want to go down the edit-war path. (And there are at least two noticeably different aspect ratios of cereal boxes on my pantry shelf right now....) XOR'easter (talk) 17:49, 17 August 2018 (UTC)
Paging Dicklyon, who has been very helpful at keeping golden ratio under control. —David Eppstein (talk) 18:20, 17 August 2018 (UTC)
Oh, I did look up the book version; it's the same as the JSTOR one, apart from pagination. XOR'easter (talk) 20:14, 17 August 2018 (UTC)
The article in no way supports the common use of this ratio. It includes an anecdotal survey of rectangles around the author's house, which include a newspaper and a cornflakes packet of numerically similar (but not identical) aspect ratios, but it does not identify the newspaper or brand of cornflakes, does not call out their numerical similarity to this ratio, and does not make any assertion that the same aspect ratio is in use for anything, let alone for other newspapers or cereals. Indeed, newspaper format lists many different aspect ratios for newspapers, none of which match. I agree that this source cannot be used to include this material. —David Eppstein (talk) 20:22, 17 August 2018 (UTC)


There has been a lot of material added to the fringier sections of this article (k-torial, superfactorial, hyperfactorial) by an IP editor over the last month or so. I've been meaning to look it over to see to what extent it is decent, but keep failing to make the time. So I am dropping this here as a reminder to myself/an invitation to anyone else who wants to take a look. --JBL (talk) 12:31, 15 August 2018 (UTC)

FYI, this appears to be the same person mentioned re: Duodecimal a couple sections up. –Deacon Vorbis (carbon • videos) 13:16, 15 August 2018 (UTC)
Now operating from (talk · contribs) —David Eppstein (talk) 05:55, 17 August 2018 (UTC)


Is the article titled Holor worth keeping? Michael Hardy (talk) 19:25, 17 August 2018 (UTC)

This article is based on a single WP:primary source, without references to any secondary source. Thus this seems WP:OR. In any case, this is a fringe theory (very few citations to the original article). Reading the WP article, it seems also that this theory consists essentially in the introduction of a lot of terminology and definitions, without any real result. I support deletion. D.Lazard (talk) 19:53, 17 August 2018 (UTC)
The article is now at AfD: Wikipedia:Articles for deletion/Holor. GeoffreyT2000 (talk) 19:59, 17 August 2018 (UTC)
Retrieved from ""
This content was retrieved from Wikipedia :
This page is based on the copyrighted Wikipedia article "Wikipedia talk:WikiProject Mathematics"; it is used under the Creative Commons Attribution-ShareAlike 3.0 Unported License (CC-BY-SA). You may redistribute it, verbatim or modified, providing that you comply with the terms of the CC-BY-SA