# Talk:Shapley–Folkman lemma

The article defines the distance between two sets, and mixes two distances. One is the infimum of distances between 2 points, which is zero, if two sets have a common point (this is what's defined in the article). The other is Hausdorff distance, which involves both suprema and infima. While the article uses the first definition, it uses properties of Hausdorff distance later.  — Preceding unsigned comment added by 160.76.7.2 (talk) 15:37, 18 November 2024 (UTC) 

The featured-article review elicited many good suggestions, which I was able to act upon to improve the article.
Additional suggestions were made that needed additional time to address. These suggestions are copied here for ease of reference. Kiefer.Wolfowitz 11:28, 5 November 2012 (UTC)

File:Shapley–Folkman lemma.svg is used in the article twice. Please choose one location and remove the other, as it is redundant to have it in the article twice. Kaldari (talk) 09:40, 11 November 2012 (UTC)

The picture has different captions. In the lede, it illustrates the SF lemma. In the early body, it illustrates the convex hull of a Minkowski sum of sets.
The repeated image is informative each time, and apparently this repetition is accepted by the other readers (many of whom have been reviewers).
Thanks, 10:06, 11 November 2012 (UTC)  — Preceding unsigned comment added by Kiefer.Wolfowitz (talk • contribs) 

It has been a while since this article has been reviewed, so I took a look and noticed lots of uncited statements. While some sections (such as math formulas) don't necessarily require citations, other sections such as "History" and its application do require them. Should this article go to WP:GAR? Z1720 (talk) 03:49, 7 May 2025 (UTC)

@Z1720: I'm sure, per WP:AGF, that the timing of this has nothing to do with WP:POINT, WP:HOUND, and the fact that we have been having a somewhat heated discussion on WT:GAR, but you must realize that as an article on my watchlist and that I significantly contributed to the Good Article nomination of, I will contribute to cleaning up at least some of the uncited statements, the ones that really do need cleaning up. Many of the uncited statements can be cited, but come under the heading of standard background definitions that anyone ready to read the article should already know. Here, let me quote WP:SKYISBLUE:
However, many editors misunderstand the citation policy, seeing it as a tool to enforce, reinforce, or cast doubt upon a particular point of view in a content dispute, rather than as a means to verify Wikipedia's information. This can lead to several forms of mildly disruptive editing which are better avoided. Ideally, common sense would always be applied, but site history shows this is unrealistic. Therefore, this essay gives some practical advice.
Not citing common knowledge and not providing bibliographic entries for very famous works is also consistent with major academic style guides, such as The MLA Style Manual and the APA style guide.
You will also note that I have already been actively maintaining it; the most recent edit, only a couple weeks ago, was by me cleaning up an error category that only started to be used on Wikipedia a couple weeks ago. And of course, since I have already been putting as much time as I have spare on cleaning up another article that you yourself brought to GAR, Matrix (mathematics), and you have promised not to close a GAR as long as there is active progress, the active progress on matrix will continue but will necessarily be significantly slowed (because I really do not have more spare time to devote to this, and I have other higher priorities as well in my editing here) while I attend to this. You're welcome. —David Eppstein (talk) 04:43, 7 May 2025 (UTC)
Oh, and while I'm quoting scripture at you: The GA criteria explicitly point to Wikipedia:Content that could reasonably be challenged as the standard for what needs citing. That, in turn, says that citations are not needed for "Facts that can be trivially verified in widely accessible sources, especially when mentioned in passing, for instance: The definitions of words". I think that covers pretty much everything in the "Preliminaries" section.
As for your claim that "History" needs citation: you appear to be confusing appropriate referencing with the superficial appearance of little clicky blue footnotes at the ends of paragraphs. 1 1/2 paragraphs of History is lacking little clicky blue editor-pacifiers. However, if you actually read it rather than scanning for those things, you would have noticed that in none of the content of the history section is there any unreferenced material. What is actually missing is the full metadata for many of the references there; that will need to be tracked down. —David Eppstein (talk) 07:15, 7 May 2025 (UTC)
Some responses to David Eppstein's post above:

I was reviewing mathematics articles because I didn't have any math articles on my personal noticed list. I rotate the categories and try to vary where I review.
If there are any HOUND or POINT concerns in my reviews, I invite editors to post on WT:GAN or other appropriate noticeboards so that this talk page can remain focused on article improvements.
WP:SKYBLUE is an essay, which says at the top "nor is it one of Wikipedia's policies or guidelines...Some essays represent widespread norms; others only represent minority viewpoints.". WP:CRC is also an essay, and while they contain great advise they might not reflect the GA criteria #2b, which requires citations at the end of every paragraph for reasonably challenged text, with normal exceptions like plot summaries and leads. The places that I marked with "citation needed" are the text where I felt the information could be reasonably challenged but were missing.
There's no timeline for making edits: as long as improvements are being made, I won't bring an article to GAR. An article at GAR does not prevent me from reviewing articles, though I try to review articles in categories where there are less articles under review.
For the metadata: I'm not sure what this refers to. Statements in the prose of an article usually need a citation with the blue footnote. Metadata might be helpful but statements also need a citation.
I think I addressed everything: feel free to ping me with questions or when this is ready for a re-review. Z1720 (talk) 13:11, 7 May 2025 (UTC)

Is GAR nowadays primarily focused on the unsourced article only? To me, citations that completely support many facts are the only thing that satisfies. Maybe this is for the one who does not know mathematics, in this case, but to me, again, there is more than that, such as improving the introduction section and rewriting it less technical topic for readers. Although I still do not know this, I think I can participate in sourcing if I have some leisure. CMIIW. Dedhert.Jr (talk) 13:30, 7 May 2025 (UTC)
@Dedhert.Jr: GARs assess all aspects of the GA criteria, of which citations are one of them. Any editor with concerns, feedback or responses about an article's adherence to a criteria are welcome to post. Note: this talk page thread is not a GAR, it's just a notice to discuss concerns informally and see if editors want to address them. If improvements are being made, I won't bring an article to GAR. Z1720 (talk) 13:45, 7 May 2025 (UTC)
@Z1720 While I have to appreciate your effort, there might be some old GAs that might need to improve. Eppstein and I have finished the article Commutative property recently. I have announced in WT:WPM regarding the future GARs based on WP:SWEEPS2023. Dedhert.Jr (talk) 13:47, 7 May 2025 (UTC)
@Dedhert.Jr: I am happy to take a look at any articles others are working on, and thanks for reviewing articles at WP:SWEEPS2023. Would you like me to post some comments on commutative property's talk page and/or put tags in the article where I think they are necessary? If anyone wants me to review an article, feel free to post on my talk page or ping me somewhere: I can't promise that I'll look right away, but I will review when I can. Z1720 (talk) 14:17, 7 May 2025 (UTC)
I won't mind. Dedhert.Jr (talk) 14:24, 7 May 2025 (UTC)
I, for one, will see immediate demands of attention to a third mathematics article that I have been maintaining, at a time when Z1720 is already demanding my attention here and on Matrix (mathematics), as confirmation of hounding, and as a violation of the spirit of the older consensus that GAR should not focus on many articles in the same area at the same time. Z1720, go find old stale cleanup tags in GAs and focus your badge-police activity on them. —David Eppstein (talk) 15:14, 7 May 2025 (UTC)
@David Eppstein emm... How is that considered HOUND? I don't get it. Some background context, please? Dedhert.Jr (talk) 16:02, 7 May 2025 (UTC)
@Dedhert.Jr: David Eppstein might have more to add, but there is a discussion at Wikipedia talk:Good article nominations#Older GARs needing participation. Z1720 (talk) 18:18, 7 May 2025 (UTC)
The issue is:
Some time ago after the GAR police squad made many rapid-fire nominations of GARs, overwhelming the ability of editors to catch up and rescue articles, a consensus developed that GARs in the same area should be more spread out over time
After the out-of-the-blue nomination for GAR of matrix (mathematics) by Z1720, I suggested that GAR nominators focus on articles that already have stale cleanup tags.
The discussion on WT:GAN blew up with the GAR police squad arguing against the (never expressed) idea that GAR needs to be shut down or slowed down, and arguing that requiring tags before nomination is a way to slow it down, rather than engaging with the idea that they should look for and nominate the articles with stale cleanup tags
Instead of following the suggestion of nominating articles with stale cleanup tags, Z1720 appears to have trolled through the articles that I brought through to GA with the aim of finding articles to add more cleanup tags to and then use those tags as an excuse to initiate a GAR. They found this one.
I was already working on the matrix article, slowly because I have limited time. This new action by Z1720 can only slow my progress on both this article and that one. That slowdown is exactly the reason for the previous consensus against rapid-fire nominations.
While GAR is a valid process in general, targeting it at a specific editor with whom you have a dispute is a violation of WP:POINT and WP:HOUND.
As my comments here stated, per WP:AGF, this rapid-fire action against a second article under my maintenance could merely be an unhappy coincidence, and is not sufficient cause to drag Z1720 to the admin boards for causing a hostile environment. A third rapid-fire action against another such article could not be passed off as coincidence. Commutativity is another such article.
—David Eppstein (talk) 19:14, 7 May 2025 (UTC)
Z1720, to respond to an important point in your earlier message: Your dismissal of WP:CRC, and substitution of your own opinion for what you think is reasonable to demand citation for, suggests that you are seriously uninformed in the standards that you have appointed yourself as an enforcer of. CRC may be an essay, but it is the essay linked in the GA rules as the definition for what this part of the rules mean. It is the standard. Imagined different rules that you have made up in your own mind have no force and cannot be the basis of a valid GAR. Do we need to set up GARR and look back through your old GARs to check that the rules you are enforcing are actually the rules that should be enforced? —David Eppstein (talk) 15:28, 7 May 2025 (UTC)
@David Eppstein: If there are any concerns about my reviews, please post in WT:GA or another appropriate noticeboard. This is not the correct place to discuss individual editor concerns. I believe the interpretation of a stricter citation requirement is the established consensus for GAs, since GAs are of a higher standard than a typical Wikipedia article. However, I'm happy to have a discussion on WT:GA to get more clarification on GA's consensus on this topic. Z1720 (talk) 17:27, 7 May 2025 (UTC)
I opened a sub-thread on Wikipedia talk:Good article nominations#Discussion at Talk:Shapley–Folkman lemma about the above discussion. Z1720 (talk) 20:24, 7 May 2025 (UTC)