Wikipedia talk:WikiProject Mathematics/Archive/2021/Sep

Requested move at Talk:Intersection form (4-manifold)
There is a requested move discussion at Talk:Intersection form (4-manifold) that may be of interest to members of this WikiProject. ASUKITE 16:06, 3 September 2021 (UTC)

New article
Hydra game was recently created over a redirect to Goodstein's theorem. Although I know nothing of this subject area, I am wondering if there should be some tie-in between the articles. Hydra game could be linked in Goodstein's. What about in the other direction - should Goodstein's be listed in a See also section? MB 15:40, 5 September 2021 (UTC)


 * Thanks for pointing that out. I added it to a See also section, as there is a relation there. -- 18:02, 5 September 2021 (UTC)

about n00,000 articles
Can anyone review a recently created article related to n00,000? These lists contain a lot of square number lists, and if they move them to the square number list, it seems like these articles can be merged.--SilverMatsu (talk) 12:10, 8 September 2021 (UTC)
 * A bold IP editor recently added squares to 100,000 and split the resulting large article. Discussion is still in progress at WT:WikiProject Numbers and its following section.  Certes (talk) 12:16, 8 September 2021 (UTC)
 * Thank you for informing me. According to the discussion, the list of numbers that has nothing to mention other than being a square number seems to be good to remove from the article.--SilverMatsu (talk) 12:48, 8 September 2021 (UTC)

list

 * 100,000
 * 200,000
 * 300,000
 * 400,000
 * 500,000
 * 600,000
 * 700,000
 * 800,000
 * 900,000
 * Thanks for bringing this up here. Yes please someone merge them back together and de-cruft. —JBL (talk) 12:16, 8 September 2021 (UTC)
 * Done. Further improvements welcome. Certes (talk) 15:39, 9 September 2021 (UTC)

Alternating factorial
I think I understand the difference between Alternating factorial and 1 − 1 + 2 − 6 + 24 − 120 + ... (former target of Alternating factorials), but the topics seem closely related and confusingly similar. Please could someone with a deeper understanding either wikilink them to each other with an explanation of the distinction, or even consider merging them? Thanks, Certes (talk) 22:51, 7 September 2021 (UTC)
 * A merge is a viable solution here. Alternating factorial is about the partial sum (i.e. with n set to a positive integer), while 1 − 1 + 2 − 6 + 24 − 120 + ... (current target of Alternating factorials) is about the infinite sum (i.e. with n set to infinity). They can also be separate articles as long as they talk about each other. — MarkH21talk 06:10, 8 September 2021 (UTC)
 * Agreed. The other distinction (if I'm reading correctly) is that the partial sum is always positive but the series leading to the infinite sum has negative values for odd n, i.e. the infinite sum is the limit (insofar as a divergent series has one) of $$(-1)^n p_n$$ where p are the positive partial sums from the other article. Certes (talk) 08:24, 8 September 2021 (UTC)
 * Yes, there is the extra alternating sign change for Alternating factorial. For now, I've retargeted Alternating factorials to Alternating factorial and placed a hatnote directing the two articles to each other. This is just a low effort solution though - feel free to add more connecting the two (or even a merge). — MarkH21talk 03:31, 11 September 2021 (UTC)

Classification theorem as a list article?
Should Classification theorem be converted into a list article at List of classification theorems? It's currently an unreferenced hybrid that attempts to define a classification theorem as a concept and then lists examples. — MarkH21talk 09:13, 16 September 2021 (UTC)
 * Note: it seems to have originally been a disambiguation page by that was then converted into an article by  (all of this was 15 years ago). — MarkH21talk 09:14, 16 September 2021 (UTC)
 * There should be a page on wikipedia explaining the concept of classification in mathematics, which is a central goal of the entire subject across many different areas. I think we should split classification theorem into Classification (mathematics) discussing and describing the concept of a mathematical classification, and List of classification theorems with a (much expanded) list as you propose.Tazerenix (talk) 09:49, 16 September 2021 (UTC)
 * I agree with the creation of Classification (mathematics), but I am not sure that List of classification theorems is a good idea: most structure theorems and most "fundamental theorems" can be viewed as classification theorems. For example, the fundamental theorem of algebra provides a classification of polynomials by the multiset of roots multiplicities. Also, classical Galois theory classifies algebraic number fields by their Galois group. So, a large part of the important theorems of mathematics should be listed in List of classification theorems, an impossible task! D.Lazard (talk) 10:53, 16 September 2021 (UTC)
 * If there isn't a page of a list of classification theorems, any page describing classification is going to include a big list anyway (as classification theorem currently does). Perhaps we could make a list page but restrict it to theorems that are very obviously classifications (although this is not particular satisfying for exactly the reasons you made)?Tazerenix (talk) 12:12, 16 September 2021 (UTC)
 * Yes, almost any important theorem can be viewed as a classification theorem. But for the even broader class, we have big list articles like List of theorems and sublists like List of fundamental theorems. An inclusion criterion can be that the theorem has to actually be called a classification theorem? I'm not sure. — MarkH21talk 16:11, 16 September 2021 (UTC)

About Domain and Region
Especially in complex analysis, these are used interchangeably and are discussed in Talk:Domain (mathematical analysis). thanks!--SilverMatsu (talk) 23:15, 20 September 2021 (UTC)
 * done.--SilverMatsu (talk) 06:23, 23 September 2021 (UTC)

Polyhedron/Johnson solid situation
There is ambiguity to whether or not uniform polyhedra are considered Johnson solids. Wikipedia tends to claim they do not. But the page "List of Johnson Solids" has recently been reformatted (vandalized?) to include them and uses a different ordering, cutting it off before all 92 solids can be named (because otherwise there would be more prismatics than non-prismatics). All metric information was also removed, leaving only piece counts.

I posted more about this on WikiProject Polyhedra (link) but it turns out that WikiProject Polyhedra is inactive.

73.220.135.34 (talk) 00:41, 23 September 2021 (UTC)
 * It's the work of a persistent block-evading and IP-hopping vandal. I have protected the Johnson solid article against anonymous users to forestall continued attacks of the same nature. Unfortunately this also shuts out good-faith anonymous editors such as the one who left the comment above. More unfortunately, the attacks also extended to the article talk page, which I also protected (for a shorter time, hoping that this will be enough). So if you have constructive changes to suggest to the article, they may need to be made elsewhere for now; alternatively, I would encourage you to get a login name. If you're worried about privacy, having a login actually gives you more privacy, not less, because the login name doesn't have to be connected in any way to your real-world identity and (unlike logged-out edits) edits made using it cannot be traced to your IP address by most other editors. —David Eppstein (talk) 07:48, 25 September 2021 (UTC)