User talk:David Eppstein

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Hi, and welcome to my User Talk page! For new discussions, I prefer you add your comments at the very bottom and use a section heading (e.g., by using the "New section" tab at the top of this page). I will respond on this page unless specifically requested otherwise. For discussions concerning specific Wikipedia articles, please include a link to the article, and also a link to any specific edits you wish to discuss. (You can find links for edits by using the "compare selected revisions" button on the history tab for any article.)

Can I download images from Wikipedia?

The WP:10 says in the first rule that one can download images on Wikipedia for free. But what about the other images that are not intended to be domain public like this one or any other similar topic of that image? Will this be considered illegal if I, for example, download it anyway? Dedhert.Jr (talk) 09:57, 8 April 2025 (UTC)[reply]

Downloading is not problematic. To show the image to you in your browser, it has already downloaded it. The question is what use you make of it. In this case, the image page shows multiple licenses, and your use must fall under one of them (not all of them). One of them, for instance, is the "Creative Commons Attribution 2.0 Generic license", which can be abbreviated as CC-BY. Under that license, you are free to make any use you want of that image as long as where you use it you state that it is under this license, credit the person who created it, and state whether you have made changes to the image. —David Eppstein (talk) 16:39, 8 April 2025 (UTC)[reply]

Weighted planar stochastic lattice, Mediation-driven attachment model, most probably authored by Hassan, M K; Hassan, M Z.

I found them during difusing of category:Graph theory and am tempted to AfD them. --Altenmann >talk 05:21, 12 April 2025 (UTC)[reply]

Question about revert

"the citation is only for the claim that Hypatia wrote in Greek; the source states that explicitly but does not describe the usage of different languages in that milieu" -> yes, that is the reason I moved the citation so that it is only after "Hypatia wrote in Greek," so that it does not cover "which was the language spoken by most educated people in the Eastern Mediterranean at the time."...is this incorrect? Yxtqwf (talk) 06:50, 15 April 2025 (UTC)[reply]

Sorry, I think I read the diff backwards. I have restored your edit. —David Eppstein (talk) 06:51, 15 April 2025 (UTC)[reply]

Schröder–Hipparchus number

Regarding my edit (from 20:45, 16 April 2025) which you undid, I added the admittedly trivial step in the formula because, (a) it then more closely resembles the definition of the hypergeometric function, and (b) as it allows to make the formula given in the short description somewhat more aesthetically appealing. None of those reasons is strong, but I found the reasoning to be more transparent that way. Schreib70 (talk) 22:14, 16 April 2025 (UTC)[reply]

@Schreib70 Sorry for butting in, but I think the additional of way you have put the trivial notation is somewhat not really helpful and adding more green bytes, especially confusing for those who does not know about how-to-differentiate-the-Sigma-notation's-index thing: it basically subtract one at both Sigma's indexes

i=1

and

n

while did the opposite (add) at the outside of the index variable

i

of

k^{i-1}

. Or maybe I was wrong. Dedhert.Jr (talk) 13:41, 17 April 2025 (UTC)[reply]

What is a Jeep-mounted pump?

While I am interested in the article you reviewed years ago El Palo Alto, I could not describe what the "jeep-mounted pump" is. But the fact that it is "clogged and bent out of shape by high winds" makes me imagine it as a pump where water passing through the pipe goes up to the top of a tree. I could not find any sources that mention this exactly, nothing but books related to the redwood. A little clarify might be helpful, since maybe some audience does not know what it is. Dedhert.Jr (talk) 13:30, 17 April 2025 (UTC)[reply]

Oh wait nevermind about this one. I am foolish for not recognizing this is actually part of a fire truck thing. Dedhert.Jr (talk) 02:00, 19 April 2025 (UTC)[reply]

Or fire jeep I guess —David Eppstein (talk) 07:04, 19 April 2025 (UTC)[reply]

@David Eppstein By the way, I have found two other things in El Palo Alto I have removed anyway. It looks like there are some kind of a 2024 presentation considered as WP:PRIMARY and WP:SYNTHESIS, as well as the OpenHistoricalMap cited with a raw link. Dedhert.Jr (talk) 08:59, 20 April 2025 (UTC)[reply]

AfD for Jnl of Nano and Nano

Hello David Eppstein,

Regarding this discussion. I took a look at the sources that discuss the delisting of this journal. I notice in your ivote that you think these do not satisfy GNG.

So, I wish to point out that the Scholarly Kitchen is published by The Society for Scholarly Publishing. Here is the info for that. Although it is a blog, the opening paragraph on that page says in part that "The Scholarly Kitchen is a moderated and independent blog aimed to help fulfill [the society's] mission..." So, being moderated and independent by a set of scholars, wouldn't this be considered RS? Perhaps you have noticed something that I have not.

Next, is the Journal Citation Reports page here. I know that this is a case of the JCR publishing about its own product (the IF rating). However, JCR is a quality source and a reliable source. This may be a unique instance where we can count on the reliablity of the information on this page (so to speak). What do you think?

Also, I have found another source: Retraction Watch here. Yes, this is a Clarivate Analytics page, but again – it is high quality and is highly reliable. I am thinking that this is one of those cases where RS is indicated, although it doesn't fit Wikipedia's specific definition.

Same with the JCR above. I think this is one of those cases where an editor in good standing can say it is reasonable to call the JCR and Retraction Watch acceptable RS, for this unique situation (the AfD discussion). So, what is your opinion?

Regards, ----Steve Quinn (talk) 02:58, 19 April 2025 (UTC)[reply]

Regardless of their reliability, none of these sources have the depth of coverage needed to satisfy WP:GNG. —David Eppstein (talk) 07:02, 19 April 2025 (UTC)[reply]

OK thanks. Your response does make sense. ---Steve Quinn (talk) 15:14, 19 April 2025 (UTC)[reply]

Default image size isn'r 220px any more

Hi, re this revert. The default image size is no longer 220px, it has been 250px for about two days now. As I noted at Template talk:Infobox election#Accessibility (which might not be on your watchlist), |upright=1.35 is equivalent to 300px only when the user is logged in and also has 220px set as their preferred thumbnail size. For those people who are logged out, a recent change to the default thumbnail size, to 250px, means that the equivalent of 300px is now |upright=1.2 - if |upright=1.35 continues to be used, the effective width will be 340px. See m:Tech/News/2025/16 (currently posted at Wikipedia:Village pump (technical)#Tech News: 2025-16 and some user talk pages). --Redrose64 🌹 (talk) 20:01, 19 April 2025 (UTC)[reply]

The image policy said that the max lead image size was upright=1.35 and as a courtesy explained that this meant 300px by default. It is completely unclear whether, after the change to the default, we should leave the max lead image size as 1.35 or as 300px. That is why I reverted the change to image policy instead of just letting one of these two options take over without discussion or consensus. —David Eppstein (talk) 20:27, 19 April 2025 (UTC)[reply]

I think we'd better continue this at Wikipedia talk:Image use policy#Lead image size. --Redrose64 🌹 (talk) 23:33, 19 April 2025 (UTC)[reply]

removing infoboxes

You are removing useful infoboxes from non-BLPs such as Abramo Colorni. Please look more careful before you remove them. You in some cases also removed valuable information and images. Andre🚐 19:59, 20 April 2025 (UTC)[reply]

I reverted the historical figures but I left Chen-Nee Chuah and Yan Rachinsky because they are BLPs, but, notice how you removed a ton of useful information and images? If you remove the infobox you should recreate it manually. Andre🚐 20:04, 20 April 2025 (UTC)[reply]

We should not ever copy content from Wikidata. Its sourcing standards are different from ours, its information is not reliable, and Wikidata content is difficult to edit for Wikipedia editors. If you want the infoboxes, turn them into purely Wikipedia infoboxes by copying the content into Wikipedia, sourcing it propertly, and making sure that all content in the infobox is included as a properly sourced claim in the article text. Until you do, I am going to remove the bad infoboxes you restored, again. —David Eppstein (talk) 21:23, 20 April 2025 (UTC)[reply]

Is there a discussion or policy precedent? Those infoboxes were not bad. Please cite a specific example that was incorrect. You also removed many images. You are also reverting a revert of a bold edit. That is highly improper. I may wish to start a thread at ANI. Andre🚐 21:31, 20 April 2025 (UTC)[reply]

Looks like you also mass reverted my changes with no rationale using rollback. Are you saying my edit was vandalism? Andre🚐 21:44, 20 April 2025 (UTC)[reply]

I boldly removed infoboxes regardless of how longstanding they were; it is you who are double-reverting and now triple-reverting my removals. You should be aware that you are in serious danger of violating WP:3RR.

As for past discussions regarding Wikidata inclusion for infoboxes, there have been many. Wikipedia:Wikidata/2018 Infobox RfC is a relevant starting point —David Eppstein (talk) 21:49, 20 April 2025 (UTC)[reply]

What are you talking about? I have not double or triple reverted. Cite a diff for that. Andre🚐 21:50, 20 April 2025 (UTC)[reply]

There is a consensus that data drawn for Wikidata might be acceptable for use in Wikipedia if Wikipedians can be assured that the data is accurate, and preferably meets Wikipedia rules of reliability cite one example of something I restored that was inaccurate. Andre🚐 21:53, 20 April 2025 (UTC)[reply]

David Eppstein If what are you are trying to say is " I believe using WikiData WP:Synth", then why didn't you say so?, Also I wouldn't agree with that idea in this case Servite et contribuere (talk) 02:08, 21 April 2025 (UTC)[reply]

No, synth is something else. Using Wikidata is relegating the responsibility for English Wikipedia content to people who are not acting as English Wikipedia editors. By doing so we have no hope of enforcing our content guidelines and policies, and we have little hope of tracking content there and making sure that if it ever was good it remains so. We should not do that. —David Eppstein (talk) 04:08, 21 April 2025 (UTC)[reply]

That is silly. You can simply go to Wikidata and check what reference is there. Using SUL, you can go edit the Wikidata entries. You have a responsibility to ensure you are doing this carefully and discriminately. Andre🚐 04:28, 21 April 2025 (UTC)[reply]

No. Wikipedia sourcing requirements are clear. Sources need to be given within the article itself. Even when a source is present in another Wikipedia article that is wikilinked within the claim that needs a source, it is not good enough. See recent discussion at Wikipedia talk:Citing sources § Citing when the source is in the hyperlink (transclusion)?. —David Eppstein (talk) 06:21, 21 April 2025 (UTC)[reply]

Actually, the thing to do per WP:V is to WP:CHALLENGE the statement if you believe it is unlikely to be verifiable, and the right thing to do if you are reverting infoboxes en masse is to consider what you should yourself restore that is easily verified. And if someone reverts you, give them a chance to restore the material, or tag it with {{citation needed}}. Also, in the cases where the infobox is summarizing material in the article body, per WP:INFOBOXCITE, if the references are in the article body, that is fine. You also removed images that probably have a fine license to illustrate the material. You should verify that you are actually not disimproving articles. Plus, as mentioned, you claimed BLP on 6 of 8 articles that were long-dead people. Andre🚐 06:28, 21 April 2025 (UTC)[reply]

You do go on, don't you. Please stop. You're not helping improve my opinion of your edits. —David Eppstein (talk) 06:38, 21 April 2025 (UTC)[reply]

If you put half as much effort into editing as you do into arguing you would have done it already.

Take a look at that article. I wrote it. Take a look at my contributions. Do you think this is a polite statement? Andre🚐 23:18, 20 April 2025 (UTC)[reply]

Notice of noticeboard discussion

There is currently a discussion at Wikipedia:Administrative action review regarding an action which you performed. Andre🚐 21:48, 20 April 2025 (UTC)[reply]

Lexicographic product of graphs

With all due respect for your substantial contributions to Wikipedia, please remember to AGF. At Lexicographic product of graphs, I appear to have missed it in the initial scan, but the article used parenthetical referencing, which has been deprecated on Wikipedia. Either way, I am merely being a WikiImp and adding maintenance tags to articles that I have added short descriptions to; have some little clicky blue footnote markers and Does that make you feel more pacified? Fnord. comes off as sarcastically telling me that my contributions are a negative asset to Wikipedia. Please consider refraining from using unnecessary edit summaries that may be interpreted as demeaning other editors, especially those less experienced than you. Best regards, it's lio! | talk | work 11:25, 21 April 2025 (UTC)[reply]

Expertise needed

Dear mr. Eppstein,

Your expertise is needed. On 22 April 2025 (02:19) I updated the article Implicational propositional calculus. My update got reverted with the argument that "I am missing the whole point which is to avoid using falsum ( $\bot$ ) in the formulas". Could you please verify that claim.

I have a more general question.

Currently, when I decide to update an article — see: Talk:Implicational propositional calculus#Substantial improvements needed — I simply make the change and then wait for any feedback or critique. Is there a way to submit a major update for collaborative review by a group of users before publishing it?^[1]

It is disappointing if a lot of work has been invested into an update, and some lone user reverts it because he does not like a semicolon. (In those cases I immediately resign if the user sticks to his guns.)

Some time ago you mentioned "consensus". I didn’t quite understand what you meant by that — consensus by whom, exactly? That group could review edits before publication.

––– Marc Schroeder (talk) 13:55, 22 April 2025 (UTC)[reply]

References

^ In the German Wikipedia all edits are reviewed (“gesichtet”) — though I’m not sure by whom — before they are placed in line.

Cumulative density function has an RfC

Cumulative density function has an RfC for possible consensus. A discussion is taking place. If you would like to participate in the discussion, you are invited to add your comments on the discussion page. Thank you. Trovatore (talk) 21:36, 22 April 2025 (UTC)[reply]

NP-Hard Graph Problems and Cryptography

Hey David,

I'm a grad student at UC Irvine, and I’ve been following your Wikipedia edits for a while, especially your work on graph algorithms and complexity theory has seriously saved me during exams. Lately, I’ve been digging into lattice-based cryptography for my thesis and came across some recent papers by Professor @Amit Sahai at UCLA. He’s been exploring secure multiparty computation, and a few of his ideas on communication models caught my eye because they seem to tie into graph theory. It got me wondering if there’s an underexplored link between NP-hard graph problems and cryptographic protocols. For example, could the complexity of something like a graph partitioning problem influence how we design secure communication networks? Professor Sahai posted a research note on his UCLA site with more detail. Here’s the link if you’re curious: https://web-cs-ucla-edu.org/.

I’d love to hear your take on this. Do you think NP-hard graph problems could play a bigger role in cryptographic protocols?Thanks for your time, and looking forward to hearing what you think! Tudorx95 (talk) 08:09, 26 April 2025 (UTC)[reply]

This is something everyone asks at some point, but the usual answer is that NP-hard functions are both too hard to have the special properties needed in cryptographic protocols, such as being a bijection, and too easy for many instances when we require cryptographic primitives to be hard in some more uniform sense over all instances. But if you're interested in the strength of cryptographic primitives, really the person you should be talking to at UCI is Stas Jarecki. It's not an area I've done any research in. —David Eppstein (talk) 16:13, 26 April 2025 (UTC)[reply]

Further removed categories

I removed the remaining "Israeli" categories on that BLP. Iljhgtn (talk) 00:32, 29 April 2025 (UTC)[reply]

Thanks. It's not impossible that she's also an Israeli citizen but we would need documentation of that before saying so. —David Eppstein (talk) 01:24, 29 April 2025 (UTC)[reply]

You are right. Iljhgtn (talk) 01:45, 29 April 2025 (UTC)[reply]

Women in Red May 2025

Women in Red | May 2025, Vol 11, Issue 5, Nos. 326, 327, 337, 338

Online events:

New: Revolutionary women | Alphabet run I & J
Continuing, year-long initiatives: #1day1woman | Music

Announcements (events facilitated by others):

WikiProject Women in Green - a Good Article editathon from 1-31 May 2025

Progress ("moving the needle"):

Statistics available via Humaniki tool. Thank you if you contributed one or more of the 1,269 articles during this period!

21 Apr 2025: 20.090% of EN-WP biographies are about women (2,061,363; 414,126 women)
24 Mar 2025: 20.070% (2,057,083 bios; 412,857 women)

Tip of the month:

Those of you who experience harassment while trying to create or improve articles about women
are welcome to bring your problems to our attention on the Women in Red talk page.

Other ways to participate:

Become a member. You can always opt-out of notifications.
Join the conversations on our talkpage.
Help us plan future events and add any general ideas on developing the project.
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--Lajmmoore (talk 09:19, 29 April 2025 (UTC) via MassMessaging[reply]

Alphabet (formal languages): indivisibility

Concerning indivisibility of alphabet symbols, I'm not sure about the example in Free_monoid#Free_generators_and_rank, where the Kleene star is applied to a set of strings rather than symbols. (I just answered Nyngwang at User_talk:Jochen_Burghardt#Would_you_mind_elaborating_the_requirement_of_"indivisible"_on_wiki_page_"Alphabet_(formal_languages)"? before I saw your edit summary at Alphabet (formal languages)).

If the monoid operations aren't freshly defined by the Kleene star construction, they can be used before it, e.g. for defining an alphabet consisting of proper strings. I guess in formal languages theory we should require that no nontrivial equations hold between any two expressions formed from alphabet members and monoid operations (epsilon and concatenation). This would imply indivisibility (but also rule out e.g. epsilon as an alphabet member). - Jochen Burghardt (talk) 17:55, 1 May 2025 (UTC)[reply]

Upcoming GAR

I am worried that there might be upcoming GARs soon. I have cleanup in Addition a few days ago still not enough to satisfy the aforementioned criterias. Some old GAs might need pay attention as well. Dedhert.Jr (talk) 07:54, 3 May 2025 (UTC)[reply]

I think it's hostile and inconsiderate to open GARs without trying cleanup tags first. I do pay attention to cleanup tags on mathematics GAs and FAs over time but I can't do that if no tags are placed. I have said something to that effect on the matrix GAR. —David Eppstein (talk) 07:56, 3 May 2025 (UTC)[reply]

Sadly I think I should put the tag instead. Dedhert.Jr (talk) 08:11, 3 May 2025 (UTC)[reply]

Notabilty on a mathematician

Morning @David Eppstein: I see this mathematician Roshdi Khalil has a note tag on the article. Do you think he is notable? He seems to have a bit of a presence but not fully sure. scope_creep^Talk 10:31, 3 May 2025 (UTC)[reply]

I think he is working in areas that are more citation-mill cargo cult mathematics than respectable mathematics, and for that reason am skeptical that he should be considered notable. But at the same time, because of the areas he works in, he has significant citations to his work, and it will be difficult to make the case that we should somehow not count the numerical evidence for WP:PROF#C1 notability. So this is one of those problematic articles that is likely to stay problematic rather than going away. —David Eppstein (talk) 17:55, 3 May 2025 (UTC)[reply]

@David Eppstein: First time I've seen cargo cult used as an analogy in this context. But what do though, what to do. I see it was yourself that posted the tag and I've read the discussion. If that journal is suspect then his main claim is suspect. In these instances, if there doubt, then I'd send it to Afd, particularly if there is a note tag on the article. It needs to be resolved somehow. I'll leave it for the moment, and think about it in the morning. I would certainly draw some discussion. scope_creep^Talk 20:23, 3 May 2025 (UTC)[reply]

(Sub)spaces homeomorphic to the Hilbert cube

Hi. I noticed that you generalized a statement on this subject in Hilbert cube, but your generalization as written was a bit too general to be correct! I looked at the source you cited and corrected it, but it took a bit of rewriting. Here's what you wrote:

Any infinite-dimensional convex compact subset of $\ell _{2}$ , and more generally every infinite-dimensional convex compact subset of any metrizable topological space, is homeomorphic to the Hilbert cube.

And here's my version, which is admittedly more clunky:

Let $K$ be any infinite-dimensional, compact, convex subset of $\ell _{2}$ ; or more generally, any such subset of a locally convex topological vector space such that $K$ is also metrizable; or more generally still, any such subset of a metrizable space such that $K$ is also an absolute retract. Then $K$ is homeomorphic to the Hilbert cube.

If you have any suggestions, I'm more than happy for you to implement them or discuss them here. Robin S (talk) 03:03, 6 May 2025 (UTC)[reply]

Correction welcome; thanks! —David Eppstein (talk) 06:41, 6 May 2025 (UTC)[reply]

ANI

There is currently a discussion at Wikipedia:Administrators' noticeboard/Incidents regarding an issue with which you may have been involved. The thread is David Eppstein and Good Article Reassessment.Thebiguglyalien (talk) 🛸 23:52, 7 May 2025 (UTC)[reply]

Admin request re: a DYK typo

I'm here because you're listed as a recently active admin. There's a typo in the DYK section of the homepage. It says "Kilmar Armado Abrego Garcia ..." and his middle name should be Armando rather than Armado. Thanks for your help. FactOrOpinion (talk) 00:39, 8 May 2025 (UTC)[reply]

Sorry to have bothered you. I see that there's a place on the talk page to report errors. Regards, FactOrOpinion (talk) 00:47, 8 May 2025 (UTC)[reply]

Yes, in future WP:ERRORS is where to go for this sort of thing. It usually gets quick attention. Anyway I fixed the typo. —David Eppstein (talk) 00:52, 8 May 2025 (UTC)[reply]

A barnstar for you!

		The Helping Hand Barnstar
		Hi @David Eppstein, at my first GA nom, your in depth review despite the article being in pretty poor shape set me on the right path to have many more successful nominations in the future. I don't know if I ever would have become a regular at the GA processes or even still be editing Wikipedia if it weren't for that. I didn't give you a barnstar at the time, because I don't think I knew what they were! So, here is one now. Thank you. IAWW (talk) 14:53, 8 May 2025 (UTC)[reply]

You're welcome! —David Eppstein (talk) 17:21, 8 May 2025 (UTC)[reply]

[1] In the German Wikipedia all edits are reviewed (“gesichtet”) — though I’m not sure by whom — before they are placed in line.

[1]