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.)

Women in Red's stub contest is starting now[edit]

As you have participated keenly in former contests, David, allow me to remind you that our three-month stub contest is starting now and will continue until the end of the year. Each month (October, November and December) recognition will be given to the winners of two different sections: one for new stubs, the other for enhancing existing stubs to start class and beyond. The contest is open to all registered members of Women in Red. Join in now and help us improve women's biographies on Wikipedia. Lot's of opportunities to create or improve biographies of women mathematicians and/or scientists.--Ipigott (talk) 19:53, 30 September 2019 (UTC)

New message from Yael[edit]

Hi David, you undid my changes in the page Degeneracy (graph theory). I added a link to the page interdependent networks (here is a link to the edit but you wrote "Undid revision 916360623 by YAEL GROSSNASS Not mentioned in linked article, no obvious reason for link" The thing is that it is mentioned in the article in the paragraph "kCore percolation". i ask the you put the link back. thanx, Yael

WP:SEEALSO explicitly says not to add "see also" links for topics already discussed in the main text of an article. —David Eppstein (talk) 17:53, 2 October 2019 (UTC)

Copyright policy[edit]

David, given recent bot editing, do you think that Wikipedia's copyright policy should state explicitly that linking to unauthorised copies of copyrighted works is forbidden? I have no skill in such matters, but perhaps you might wish to propose it. Chiswick Chap (talk) 15:23, 2 October 2019 (UTC)

A barnstar for you![edit]

Original Barnstar Hires.png The Original Barnstar
Nice new article on Anita Feferman! A fascinating, notable woman who I'm glad to have learned about. Babajobu (talk) 22:57, 5 October 2019 (UTC)
Thanks! —David Eppstein (talk) 23:04, 5 October 2019 (UTC)

Boyer–Moore majority vote algorithm[edit]

David, you have reverted my change for Boyer–Moore majority vote algorithm page with comment that in provided sequence ([1,0,2,1]) there is no majority element. I think that 1 is majority element (counts of 1 eq 2, 0 => 1, 2 => 1). Could you please explain why it is not majority element from your point of view? Thanks! — Preceding unsigned comment added by Stan Putrya (talkcontribs)

Majority means that its number of occurrences is more than half the total, as the article already clearly stated before your change. In this example, the number of occurrences of 1 is 2, and half the total number of occurences is also 2. It is not true that 2 is more than 2. For a list of four items, one of them would have to be present for three out of the four items to be a majority element. —David Eppstein (talk) 20:19, 7 October 2019 (UTC)
Thanks a lot for explanation. I was confused with discussion about majority algorithms. Now I reread original doc and I see that my understanding was incorrect. Thanks a lot for fix it! —Stan Putrya (talk) 21:32, 7 October 2019 (UTC)

Šarūnas Raudys[edit]

Do you think that Šarūnas Raudys's h-index of 23 [1] is high enough to meet WP:PROF? I would say probably not but it seems borderline and of course I don't know nearly as much about (notability in) the field of computer science as you do. IntoThinAir (talk) 13:18, 9 October 2019 (UTC)

I think he passes WP:PROF#C1, but not so much because of the h-index (that value could mean a lot of things) but because the higher end of his citation counts is quite high (one paper with over 1000 cites and five others with over 100). —David Eppstein (talk) 16:02, 9 October 2019 (UTC)

Maximum subarray problem: citation style[edit]

Hi David Eppstein!

I recently tried to improve the article Maximum subarray problem, hoping this will end the "max(0,...)" vs. "max(x,...)" debates edits, and also satisfy the "more footnotes" request.

However, I definitely messed up the citation style mix even more, and I intend to fix that in the near future. Since you were involved in the article right from the beginning and are its main contributor, I feel I should follow your citation style preferences. I guess, they are {{harvtxt}}, aren't they? I'm not yet too familiar with this style.

If you could provide me a representative article using your preferred style, I'd try to adapt Maximum subarray problem to it. I'd like to keep the page-reference information in some form (needn't be {{rp}}, of course); would that be ok?

Best regards - Jochen Burghardt (talk) 14:11, 11 October 2019 (UTC)

Number Theory[edit]

It was a surprise to me that someone nominated the page at this point. It is clear that there were some minor issues that absolutely had to be addressed first (the section that needs expansion, the errors in citations) and some broader issues that needed more work (sources for the second half of the article -- though that's a bit of a tough issue, since many of the statements are second nature to a professional, and hence hard to source). Still, it is very helpful to have feedback.

Two issues: What do you mean precisely by "one specific and contentious interpretation of the meaning of the tablet"? The :tablet does contain a list of what is conventionally called Pythagorean triples, and they are labelled as such. As :for applications, the field is indeed wide open, but we mention at least two opposing views. We could also include a :more recent response to Robson - is that what you imply is missing? As for why "half of the subfields are grouped into "Main subdivisions" and half into "Recent approaches and :subfields"" - it is more or less clear that some subfields are much newer and well defined than others (the name :"additive combinatorics" is less than 20 years old, though the field has been around since the 1960s, or in some :sense for longer). Does the division seems too arbitrary or unnecessary? If so, we can talk about removing it, but I :am sure I am not the only one who wonders where exactly the problem lies. Also: wouldn't nominating the article for a B-class review be a logical first step, once the issues above are addressed? Garald (talk) 11:15, 14 October 2019 (UTC)

What is the context here? Also, there is no such thing as nominating an article for B-class review. B-class is something that can be determined by a single editor or (if disputed) consensus of editors on the article talk page; it has no formal nomination process. —David Eppstein (talk) 16:16, 14 October 2019 (UTC)
The context is that someone (who was not a regular editor) nominated the Number Theory page for "Good article" status a few months ago. You kindly left some remarks in the talk page as to why it counted as a quick fail.
I would be glad to know what you meant by your remark on that Plimpton tablet. Do you mean we should simply leave most of the discussion of what it is and what it is not to the page on the tablet? I would also like an answer to my other questions.
Do you mean we should simply tag the page as B-class? Is there any obvious way in which the page fails to fulfill the criteria for B-class right now? Are the criteria for "good article" in some sense intermediate between those for B-class and A-class? Garald (talk) 13:43, 15 October 2019 (UTC)

About De Bruijn sequence...[edit]

Hello, You write about Euler sequence but the sequence continues on the next line and it has another set of 000 so it total there are 3 of them. Kigelim (talk) 02:38, 17 October 2019 (UTC)

In the usual convention I've seen for describing a path or cycle, something like "x, y, z, w" would have three edges, xy, yz, and zw. If you want a fourth edge to make it into a cycle, you should repeat the starting vertex, "x, y, z, w, x" so that you end back where you started with the four edges xy, yz, zw, and wx. Now in the example we're talking about, in De Bruijn sequence, we want the edge that loops from 000 to itself to be covered. So we need two consecutive 000's somewhere in the sequence. Having a 000 at the start and another copy of 000 at the end of the sequence of vertices doesn't count; it needs to be in the middle somewhere. You removed that repetition in the middle, making it wrong. —David Eppstein (talk) 05:20, 17 October 2019 (UTC)

Slo-mo EWing IP[edit]

Special:Contributions/ Warned prior. Please take action as you see fit. EEng 07:53, 17 October 2019 (UTC)

Humbly requesting you take another look at this. EEng 07:49, 21 October 2019 (UTC)
Adding Special:Contributions/ and Special:Contributions/ for comparison. There is also Special:Contributions/ Regards! --T*U (talk) 07:55, 21 October 2019 (UTC)
Ok, fine, blocked. —David Eppstein (talk) 15:56, 21 October 2019 (UTC)

DYK for Dona Strauss[edit]

Updated DYK query.svgOn 21 October 2019, Did you know was updated with a fact from the article Dona Strauss, which you recently created, substantially expanded, or brought to good article status. The fact was ... that mathematician Dona Strauss left South Africa over apartheid, lost a faculty job at Dartmouth for joining an anti-war protest, and helped found European Women in Mathematics? The nomination discussion and review may be seen at Template:Did you know nominations/Dona Strauss. You are welcome to check how many page hits the article got while on the front page (here's how, Dona Strauss), and it may be added to the statistics page if the total is over 5,000. Finally, if you know of an interesting fact from another recently created article, then please feel free to suggest it on the Did you know talk page.

Gatoclass (talk) 00:02, 21 October 2019 (UTC)

Dona Strauss[edit]

Regarding this, it's just a script. If you have issues then please raise with @Ohconfucius:. Also please restore the DMY tag. GiantSnowman 17:20, 21 October 2019 (UTC)

I don't care whether it's a script, it's inappropriately changing an acceptable date format to a different date format. Also, no, I will not restore the tag, because it will have the same effect — the citation templates use that tag to convert date formats. —David Eppstein (talk) 17:22, 21 October 2019 (UTC)
It's well established through general consensus that South African articles use dmy dates and Commonwealth English. The tagging therefore is entirely appropriate. You don't own the article, so you should allow the tagging, which also has general consensus. If you are unhappy that the {{use dmy dates}} tag automatically converts all dates within citation templates, you should take up the issue at I'm not exactly sure where, but you could try Template talk:citation, or with User:Trappist the monk -- Ohc ¡digame! 19:23, 21 October 2019 (UTC)
The article does use dmy dates. For the dates of publications and dates in running text. It is also well-established in MOS:DATEUNIFY that using numeric dates for reference accessdates is one of the acceptable formats, and through MOS:DATEVAR that you should not change article date formats that already meet the MOS. GiantSnowman's attempts to change the date format are in violation of the MOS, and your support of GiantSnowman does you no credit. There are no national-tie based arguments that apply in this case, because the article already uses the dmy format that national ties would suggest. At this point the process is clear: work on the article talk page to establish a consensus for making the change, or don't change it. —David Eppstein (talk) 20:10, 21 October 2019 (UTC)
I'm not changing the date format. There are two formats - DMY and MDY. As you say the article uses DMY and so I tagged it accordingly and appropriately. GiantSnowman 20:50, 21 October 2019 (UTC)
False and false. There are at least four formats allowed by MOS: pure DMY, DMY with numeric accessdates, pure MDY, and MDY with numeric accessdates. You changed one to another. —David Eppstein (talk) 20:52, 21 October 2019 (UTC)
As the primary architect of the presentation (not the content – I stayed out of that) of MOS:DATEFORMAT and its subsections such as MOS:DATEUNIFY – in other words, as someone intimately familiar with its provisions – I will say that David Eppstein is absolutely correct about the variety of formats. EEng 22:40, 21 October 2019 (UTC)
You're really that precious about dates? JHC. GiantSnowman 08:08, 22 October 2019 (UTC)

Henry Crapo (mathematician)[edit]

I wrote an article on Henry Crapo. It's my first time moving an article directly to mainspace, and I messed up and first moved the talk page to an article. Perhaps you'd be willing to look and make sure that I cleaned up correctly? (Reaching out partly because I think the article will be of some interest for you.) Thanks so much! Russ Woodroofe (talk) 03:54, 25 October 2019 (UTC)

Yes, I had seen Oxley's blog post and wondered whether maybe we should have an article on him. I'm sure there are some small cleanups still to be made but it looks mostly ok to me. —David Eppstein (talk) 03:57, 25 October 2019 (UTC)

Style question regarding Gleason's theorem[edit]

I've been intermittently working on Gleason's theorem, which I originally found in a state that I could barely understand even knowing what it was supposed to be about, and now I'm wondering: is the block-quoted statement in the lede too technical for that early in the article? That part is mostly a leftover from years ago, which I smoothed out a bit. On this topic, I think the "write one level down" means pitching to a physics or mathematics undergraduate; the amount of popularized writing on this topic is basically nil. XOR'easter (talk) 18:47, 26 October 2019 (UTC)

There's a short gloss of this in Andrew M. Gleason that I worked on as part of bringing Gleason's article up to Good Article standard, but as I recall for that I had to ask a local student working in quantum computing to check my work, because I don't understand this subject much myself. Anyway, the quoted paragraph does indeed look unnecessarily technical, but I'm not sure how to make it less so. —David Eppstein (talk) 18:57, 26 October 2019 (UTC)
Thanks. Feedback from someone who isn't deep into quantum information yet who doesn't run in terror from an equation is actually really helpful! I may try to adapt the gloss in Andrew M. Gleason for the lede and replace the overly technical paragraph, since the next section explains the theorem statement in a more decompressed way. XOR'easter (talk) 22:14, 26 October 2019 (UTC)

Your links to CiteSeerX[edit]

Hello, I hope you can help me understand more about the copyright practices you recently asked other users to adopt. I noticed that a few articles created by you link CiteSeerX via Google Scholar, for instance Heidi K. Thornquist links [2] via [3]. Can you elaborate on what you see as the copyright implications of such links? Thanks, Nemo 13:31, 27 October 2019 (UTC)

I have gone over this over and over with you, so it is hard to see this as a good faith question rather than as an attempt at a gotcha. But in case you still somehow don't understand:
  1. Google scholar does not make copies of publications. It merely collects links to them, some of which might be problematic. They have their own policies on which links to collect, which are different from Wikipedia's policies on which links to collect. In contrast, CiteSeerX is more like Sci-Hub: it actively makes copies of stuff and keeps it around for other people to use. Among these, seems to be very careful about copyrights; I have never seen a problematic link there. Sci-hub is explicitly anti-copyright and I think all links there are likely problematic. CiteSeerX is somewhere in between: most links are good, because most copies of scientific papers that can be found online directly are good, but they aren't very careful and also incorporate links that don't meet our standards.
  2. Our standards for external links are to only allow links to copies of copyrighted material that are made available by the author or publisher. CiteSeerX provides provenance for its copies that show whether this is true for each copy. When we link to CiteSeerX, we need to check manually whether this is true, and avoid making the link otherwise.
  3. In the case you mention, the link goes to Google Scholar (so, not someone who makes copies of papers and re-serves them, but merely a collector of links), but more specifically it goes to a curated page of Google Scholar entries made by the author of the publications, Thornquist herself. So it's doubly unproblematic, first because it's not a source of files and second because it has the approval of the author.
David Eppstein (talk) 16:47, 27 October 2019 (UTC)

Computational linguists[edit]

Thanks for reverting my edit on Bonnie Dorr. If we follow the path you suggest, then we would also need to delete Category:Computational linguistics researchers from Eduard Hovy, Aravind Joshi, Ronald Kaplan, Lauri Karttunen and Jun'ichi Tsujii. I'm always a bit confused about the hierarchical categories because if you look specifically, for instance, for computational linguists, you are likely to land on the names under Category:Computational linguistics researchers. You don't necessarily see or bother about Category:Fellows of the Association for Computational Linguistics. But I suppose we should be consistent - which means deleting the names above too. Right? I am surprised, btw, that many other notable participants are not included in the category, perhaps also for hierarchical reasons, e.g. Yorick Wilks, Makoto Nagao.--Ipigott (talk) 17:42, 28 October 2019 (UTC)

I think you're right. The Fellows category doesn't seem to fall under any of the usual reasons for making categories non-diffusing. —David Eppstein (talk) 18:05, 28 October 2019 (UTC)

DYK nomination of Anne C. Morel[edit]

Symbol question.svg Hello! Your submission of Anne C. Morel at the Did You Know nominations page has been reviewed, and some issues with it may need to be clarified. Please review the comment(s) underneath your nomination's entry and respond there as soon as possible. Thank you for contributing to Did You Know! Yoninah (talk) 00:13, 29 October 2019 (UTC)

November 2019 at Women in Red[edit]

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November 2019, Volume 5, Issue 11, Numbers 107, 108, 140, 141, 142, 143

Check out what's happening in November at Women in Red...

Online events:

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Stay in touch: Join WikiProject Women in Red / Opt-out of notifications

--Rosiestep (talk) 22:57, 29 October 2019 (UTC) via MassMessaging

Aaron Hawkins[edit]

Regarding your infobox edit:

  • On nationality, I agree that it's unsourced so far. But I notice that his Amazon author profile [4] lists him as born in New Mexico. Do you think that would suffice? (Googling "Aaron Hawkins" "New Mexico" gives some other sources, though I didn't see anything so concrete.) Otherwise, should "American" also be removed from the article lede?
  • Comment that I'd put the infobox header to match the article title, and used the birth name for the fuller form of his name. But since he publishes mainly as Aaron R. Hawkins, perhaps the latter should be the article title. Anyway, I certainly won't mess with it until clarity on page moves comes down. Do I have the style right here?

Thanks! Sorry for the basic questions. It's fun to see the article shaping up! Russ Woodroofe (talk) 18:34, 31 October 2019 (UTC)

To answer my own question, he has a separate homepage as an author. [5] (For his technical book, and also a children's book.) That is probably enough to leave him as American. Will add it back! Russ Woodroofe (talk) 18:40, 31 October 2019 (UTC)
Yes, if we have a source that lists his birthplace, I think we can use it despite it being more-or-less self-sourced. If it's going back into the infobox it should also be stated in the article text. It should not generally be the case that an infobox provides information that does not come from the main article text. —David Eppstein (talk) 19:51, 31 October 2019 (UTC)
I don't see that I have ever touched this article or the disambiguation page. If I had, the incoming links would have been fixed. bd2412 T 16:29, 1 November 2019 (UTC)
Sorry, my mistake, it was Waddie96 who failed to fix the incoming links. I'm not sure which history I was looking at to think it was you, but obviously it wasn't. —David Eppstein (talk) 17:44, 1 November 2019 (UTC)
Which incoming links? I'm sure I resolved the incoming links for Aaron Hawkins which were leading to the dab instead of Aaron Hawkins (engineer). I assumed that would fix the incoming links to Aaron Hawkins (engineer), but if I missed some please point them out to me. comrade waddie96 ★ (talk) 18:02, 1 November 2019 (UTC)
You missed the one in the header of this talk page section, and two on Template:Did you know nominations/Aaron Hawkins, at least. —David Eppstein (talk) 18:20, 1 November 2019 (UTC)

Recent edits[edit]

Information icon There is currently a discussion at Wikipedia:Administrators' noticeboard/Incidents regarding an issue with which you may have been involved. --Rupert Loup (talk) 00:43, 9 November 2019 (UTC)

Whee! It's Australian throw-toy funtime. —David Eppstein (talk) 05:20, 9 November 2019 (UTC)

List of amateur mathematicians[edit]

Are you going to remove Pierre de Fermat from List of amateur mathematicians? --Toploftical (talk) 00:19, 10 November 2019 (UTC)

I wasn't planning to. Fermat was, professionally, a lawyer, so he fits the definition of someone who worked outside any mathematical field but made contributions to mathematics on his own time. I probably wouldn't argue strongly if someone else removed him. But your argument is about Martin Gardner. Martin Gardner was, professionally, an author of works aimed at amateur mathematicians. That is, he was a type of professional mathematician, not an amateur. The fact that his audience was largely amateur is irrelevant. Returning to Fermat, one could argue that certain types of lawyers (I'm not sure Fermat was one) largely have criminals as their clientele. But that doesn't make those lawyers themselves criminals. It's the same with Gardner and amateurs. —David Eppstein (talk) 00:26, 10 November 2019 (UTC)

Collatz conjecture[edit]

One user answered at and got 288 votes. Since many people seem to agree on its connections to number theory, wouldn't that be sufficient, at least for the prime factorization claim? There are obviously no absolute connections until a proof of the conjecture arrives. 37KZ (talk) 21:37, 10 November 2019 (UTC)

No. See WP:RS. Reddit threads are definitely not reliable sources of anything, and neither are stackexchange posts. And "connections to number theory" is a very different thing than what you wrote on the Collatz conjecture article about connections to prime factorization or the Riemann hypothesis, two very specific pieces of number theory. —David Eppstein (talk) 21:38, 10 November 2019 (UTC)
Whatever. The StackExchange thread resulted in an accepted answer connecting the conjecture to how prime factorization of numbers changes with addition that got 288 votes. That was my point. 37KZ (talk) 21:57, 10 November 2019 (UTC)
So that doesn't change anything then? 37KZ (talk) 22:07, 10 November 2019 (UTC)
No. We don't measure reliability by number of votes on an amateur/student online forum. —David Eppstein (talk) 22:23, 10 November 2019 (UTC)

easy calculus removed on the golden rhombus article[edit]


you've removed twice my little accretions of material on the golden rhombus Wikipedia english article, because they were unsourced:

But these little accretions of material are just my "personal" easy calculus, which anyone having passed scientific A levels can easily check, all the more so that i write many calculus details...!

§:-P §:'(

2A01:CB00:8697:8100:E19D:41A2:70F9:586D (talk) 17:02, 12 November 2019 (UTC)

They are original research and they need published sources to be included. —David Eppstein (talk) 18:12, 12 November 2019 (UTC)