User talk:David Eppstein

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Wikipedia:Administrator intervention against vandalism

We need administrator attention at Wikipedia:Administrator intervention against vandalism. CLCStudent (talk) 20:38, 1 October 2015 (UTC)

Neither did this guy: Is it a pseudonym or a real name? — Preceding unsigned comment added by Beta Ms Cousin (talk • contribs) 12:33, 29 September 2015 (UTC) — Preceding unsigned comment added by 81.161.189.243 (talk)

Clustering coefficient

Opened up a discussion at https://en.wikipedia.org/wiki/Talk:Clustering_coefficient#Triplet_contradiction Michaelmalak (talk) 19:33, 5 October 2015 (UTC)

RfC on an Article in Which You've Participated

A RfC on an article in which you've commend on has been opened here. This is a courtesy notification you may ignore if it is of no interest. LavaBaron (talk) 06:33, 12 October 2015 (UTC)

Ptolemy's Theorem

Hi David

You removed a whole lot of quite important historical stuff on Ptolemy's theorem. Can't say I'm very impressed particularly re the proof via Ptolemy's theorem of a very ancient result which I will quote from Copernicus in Stephen Hawking's "On the Shoulders of Giants."

Moreover the side of the pentagon, the square on which is equal to the sum of the squares on the side of the hexagon and on the side of the decagon (Elements XIII, 10) is given as 117557 parts.

Any appreciation of the history of trigonometry needs to have due regard for the extensive deployment of the Almagest theorem. I think that's what you were perhaps missing when you pulled all the examples I included to that effect. Elements XIII, 10 is an appallingly clumsy way of reaching the above result as compared to the far more elegant proof via "Theorema Secundum".

Neil Parker (talk) 13:40, 13 October 2015 (UTC)

(This was a year ago. I really should add a note to the talk of my talk page asking people here to provide diffs. For context, Neil is referring to this set of changes. —David Eppstein (talk) 15:59, 13 October 2015 (UTC))

Your GA nomination of Reversible cellular automaton

The article Reversible cellular automaton you nominated as a good article has passed ; see Talk:Reversible cellular automaton for comments about the article. Well done! If the article has not already been on the main page as an "In the news" or "Did you know" item, you can nominate it to appear in Did you know. Message delivered by Legobot, on behalf of Edwininlondon -- Edwininlondon (talk) 03:41, 14 October 2015 (UTC)

Category:Order of the Netherlands Lion and subcategories relisted

Hello. You participated in either the CFD discussion to delete the above category and its subcategories or the DRV discussion regarding those categories (or both). The result of the DRV was to relist the categories for discussion. This is a notification that they have now been relisted for discussion here. Good Ol’factory ^(talk) 23:42, 14 October 2015 (UTC)

DYK for Reversible cellular automaton

Cas Liber (talk · contribs) 02:02, 15 October 2015 (UTC)

DYK for Hazel Findlay

Cas Liber (talk · contribs) 12:16, 18 October 2015 (UTC)

DYK for Pia Nalli

The DYK project (nominate) 12:02, 19 October 2015 (UTC)

You do not delete what you think are suboptimal or inconsistent !votes, you comment on them

Per WP:TPG, the deletion discussion follows the norms of a talk page, and your reversion falls outside of the allowed WP:TPO edits. You are of course welcome to comment, suggesting alternative actions implicit in my !vote. You are not allowed to remove a relevant !vote, thereby interfering with other potential editors who may agree or disagree, suggest better alternatives, be spurred to act, and so on. You're an experienced editor and admin, you know better. Consider yourself trouted. Choor monster (talk) 12:22, 19 October 2015 (UTC)

Never mind, I completely missed the "P". The trout boomeranged. Choor monster (talk) 15:46, 19 October 2015 (UTC)

Daily Mail reference: To be replaced with Times of India citation

Hi David, Thanks a lot for removing the Daily Mail cite from the following article. https://en.wikipedia.org/w/index.php?title=Dinesh_Singh_(academic)&oldid=686452489 (Revision as of 05:28, 19 October 2015)

I was not aware that Daily Mail is not reliable source. After your edit, I did some research and completely agree with you reason and decision.

However, the DUTA ("DUTA is a teachers representative body of the teachers of Delhi University. The elections for its office bearers are conducted every two years.") has made allegations and representations about the authoritarian and megalomaniac administrative style of Dinesh Singh. Therefore, in support of the removed text, please find an alternative reliable source: I am quoting from the news report in Times of India.

"In a second resolution, demanding the dismissal of Singh, the GBM stated that it "condemns the DU VC for his insulting and defamatory remarks about DU teachers, in general, and the School of Open Learning in particular. In an unprecedented display of megalomania, Dinesh Singh has spared neither eminent educationists who have questioned the wisdom of the FYUP nor the parliament where several questions on this issue have been raised"."

One more reliable source - Statesman:

If you agree, can I put back the statement that you deleted and use this cite instead of Daily Mail.

Thank you, Annie 70.51.29.124 (talk) 15:45, 19 October 2015 (UTC)

References

That whole section is somewhat problematic, out of balance with the rest of the article. But I have no specific objection to those other sources. —David Eppstein (talk) 17:14, 19 October 2015 (UTC)

DYK for Hinke Osinga

Materialscientist (talk) 02:13, 20 October 2015 (UTC)

A cup of tea for you!

With this ever dramatic world including WikiDrama, here's a cup of tea to alleviate your day! This e-tea's remains have been e-composted SwisterTwister talk 07:08, 22 October 2015 (UTC)

Vandalism on the François Viète page

Professor Eppstein, I wish to draw your attention to some vandalism on the François Viète page , where you seem to have made some substantial contributions. I don't believe I'm experienced enough to revert the changes correctly, and hope you are able to do so. My Other Head (talk) 17:53, 22 October 2015 (UTC) — Preceding unsigned comment added by My Other Head (talk • contribs) 17:48, 22 October 2015 (UTC)

References

Fixed — thanks for calling this to my attention. —David Eppstein (talk) 17:56, 22 October 2015 (UTC)

Cycle detection

I saw that you have shepherded this page before, and wanted to ask if I'm crazy or not. Back in 2010 an anon added explanatory comments, but used the word 'circle' instead of 'cycle'. That rather bothers me. Shouldn't those be 'cycle'?

When explanations confuse me, I start to worry the mental ECC is wearing out... Shenme (talk) 22:40, 24 October 2015 (UTC)

Yes, I think "cycle" would be better there. —David Eppstein (talk) 23:05, 24 October 2015 (UTC)

FYI

A page whose deletion discussion you participated in was re-added and nominated for deletion again. See: WP:Articles_for_deletion/Karen_Franklin_(2nd_nomination) Barcaboy2 (talk) 16:47, 26 October 2015 (UTC)

MDPI

Hi David, MDPI was removed from Mr. Beall's list of "predatory publishers" (www.scholarlyoa.com/publishers/) after we submitted an appeal directly to him. We previously discussed about moving the subject to the main body of the article. Do you still believe that the lead of the article needs to refer to MDPI as "predatory"? Regards, Alistair 46.140.24.118 (talk) 14:05, 30 October 2015 (UTC)

Your GA nomination of Reuleaux triangle

Hi there, I'm pleased to inform you that I've begun reviewing the article Reuleaux triangle you nominated for GA-status according to the criteria. This process may take up to 7 days. Feel free to contact me with any questions or comments you might have during this period. Message delivered by Legobot, on behalf of Spinningspark -- Spinningspark (talk) 20:40, 30 October 2015 (UTC)

You're invited! Women in Red World Virtual Edit-a-thon on Women in Science

You are invited! Join us remotely! World Virtual Edit-a-thon on Women in Science

Dates: 8 to 29 November 2015 Location: Worldwide/virtual/online event Host/Facilitator: Women in Red (WiR) in collaboration with Women scientists: Did you know that only 15% of the biographies on Wikipedia are about women? WiR focuses on "content gender gap". If you'd like to help contribute articles on women and women's works, we warmly welcome you! Sponsor: New York Academy of Sciences Event details: This is a virtual edit-a-thon hosted by WiR in parallel with a "phyisical" event during the afternoon of Sunday, November 22 in New York City. It will allow all those keen to improve Wikipedia's coverage of women in science to participate. As the virtual edit-a-thon stretches over three weeks, new participants will be able to draw on the assistance of more experienced editors while creating, translating or improving articles on women who are (or have been) prominent in the field. All levels of Wikipedia editing experience are welcome. RSVP and learn more: →here←--Ipigott (talk) 10:49, 31 October 2015 (UTC)

Reference errors on 31 October

Hello, I'm ReferenceBot. I have automatically detected that an edit performed by you may have introduced errors in referencing. It is as follows:

• On the Reuleaux triangle page, your edit caused an unsupported parameter error (help). (Fix | Ask for help)

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Comment

Hello David Eppstein, I asked a question about your recent edits on the Applied Mathematics talk page. Please see: https://en.wikipedia.org/wiki/Talk:Applied_mathematics#Further_reading_section_-please_explain_undo_Comment

Thank you, --CuriousMind01 (talk) 01:21, 2 November 2015 (UTC)

Fractalgrid... comment fixed

Regarding your comment for the introduction. I believe I fixed it. https://en.wikipedia.org/wiki/Fractalgrid — Preceding unsigned comment added by LunaLinus (talk • contribs) 01:46, 3 November 2015 (UTC)

IEEE Conferences & Kenes Group

It is very difficult to create the new articles as experienced editors are merging, so I am going to keep IEEE conferences in main page, as parent article is available. It may not be informative to scientific /academic community. No Parent article available to Kenes Group, I request you to keep this new article, let me improve sources on timely basis. Dentking07 (talk) 14:31, 3 November 2015 (UTC)

Deletion of Erdős number information

Hi! Thank you for all of your contributions!  :) I noticed that one of them had been deleted, which I think is unjustifiable. I just reverted a similar deletion, explaining why. Your point of view on the matter would be greatly appreciated.

Kragen Javier Sitaker (talk) 04:43, 4 November 2015 (UTC)

Ancient Egyptian Cantor set?

Ancient Egyptian Cantor set? From Description d'Egypte, Paris, 1809-1828

David, you may be amused by this properly cited bit of wild speculation. All the best, Chiswick Chap (talk) 13:44, 7 November 2015 (UTC)

Disambiguation link notification for November 9

Hi. Thank you for your recent edits. Wikipedia appreciates your help. We noticed though that when you edited Leslie Lee (playwright), you added a link pointing to the disambiguation page Richard Wright (check to confirm | fix with Dab solver). Such links are almost always unintended, since a disambiguation page is merely a list of "Did you mean..." article titles. Read the FAQ • Join us at the DPL WikiProject.

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Hail major WikiGnome

Hi David, Thank you for your nice addition to Bill Casselman (mathematician). I have often noticed such edits by you and consider you the prince of the WikiGnomes. You really ought to consider adding the WikiGnome topicon to your home page: {{WikiGnome topicon}. On another topic, I spent some time a while back (as Foobarnix) cleaning up all the Sporadic group articles such as Mathieu group M11 and so on – and also worked on the then lame Template:Group theory sidebar. (Editor GodMadeTheIntegers then did a fantastic job of cleaning it up. Why doesn't that guy get a home page so we can thank him?) Have you looked at any of those pages? It seems like your talents would be a great fit. IAC thanks for all your fine work.--Toploftical (talk) 17:02, 19 November 2015 (UTC)

ArbCom elections are now open!

Hi,
You appear to be eligible to vote in the current Arbitration Committee election. The Arbitration Committee is the panel of editors responsible for conducting the Wikipedia arbitration process. It has the authority to enact binding solutions for disputes between editors, primarily related to serious behavioural issues that the community has been unable to resolve. This includes the ability to impose site bans, topic bans, editing restrictions, and other measures needed to maintain our editing environment. The arbitration policy describes the Committee's roles and responsibilities in greater detail. If you wish to participate, you are welcome to review the candidates' statements and submit your choices on the voting page. For the Election committee, MediaWiki message delivery (talk) 16:11, 23 November 2015 (UTC)

Revdel

Please also revdel this edit, by the same IP who made the edit you revdel'ed a short time ago. Thanks. General Ization ^Talk 02:43, 25 November 2015 (UTC)

Done — thanks for pointing this out. —David Eppstein (talk) 03:47, 25 November 2015 (UTC)

Help with editing

Hi! I see you like editing in geometry and biographies. Would you like to help me to make an article on Jan Koenderink? I have made an initial stub, but I don't know very well how to improve it. I liked his book Solid Shape so much that I decided to try to create an article about him. :) — Preceding unsigned comment added by TimidSings (talk • contribs) 06:25, 27 November 2015 (UTC)

I can't find more sources... Maybe it was a bad idea to start an article when there are so few references out there. He is clearly notable but it's also clear that there are so few sources from which to build the article. :/ Sorry for asking help in this impossible case. :) — Preceding unsigned comment added by TimidSings (talk • contribs) 09:06, 27 November 2015 (UTC)

He clearly passes WP:PROF. I cleaned up the article a bit today and added a couple more references. —David Eppstein (talk) 01:51, 29 November 2015 (UTC)

Fact check statement about smallest cubic graph with no Hamiltonian path

I was going to add a statement to Hamiltonian path about the smallest cubic graph that doesn't have a Hamiltonian path (not cycle). I thought this was one of the Zamfirescu graphs with 88 vertices described at [1] but just before I added the statement I realized that paper refers only to planar cubic graphs that are also 3-connected. Has anyone found the smallest simple cubic graph with no Hamiltonian path? I find that the Tutte graph does have a Hamiltonian path (just not a Hamiltonian cycle), and so do snarks like Petersen and other small cases. I recalled and found your family of cubic graphs with polylog longest paths at [2]. Does that family yield the smallest? I couldn't find much in the literature for "untraceable graph" and "nontraceable graph" -- looks like the lack of Hamiltonian paths is not as well-researched as the lack of Hamiltonian cycles. -- 174.152.78.22 (talk) 19:17, 28 November 2015 (UTC)

Planar and cubic but wth no Hamiltonian path

Even for planar graphs, the answer is much smaller than 88; see the figure. I suspect this may be the smallest one (for cubic graphs, unconstrained by connectivity or planarity) but don't have a reference at hand. A similar construction with two lobes instead of three gives an even smaller cubic graph with no Hamiltonian cycle. —David Eppstein (talk) 19:48, 28 November 2015 (UTC)

Thank you for the quick response. Has this work been published by you or anyone else? I would like to cite it if I add it to the article if you don't consider it to be OR. -- 174.152.78.22 (talk) 20:23, 28 November 2015 (UTC)

It's not published that I know of. I tried a quick Google scholar search but didn't find anything relevant. As you say, there is much more work on Hamiltonian cycles than paths. —David Eppstein (talk) 01:08, 29 November 2015 (UTC)

Fibonacci 's Number

Excuse me, apart of the fact that it would be much more apprechiated a nicer way of describe other people work, can we speak about the erasing of our contribution to the section "in Nature". The work of the astrophysicist Nikolai Kozyrev has been studied, analyzed and experimented for half of a century and it's continuing to be analyzed, by mathematicians, physicists and natural scientists. If there is the need to offer more proof and more references we will, but let's speak about it formally and civilly. There is a reason why many people are researching on this topics and eventhough many of the results are pseudoscientific conquers for a mediatic wave of more misteries then how we had starting, others, like Kozyrev's, Santilli's, Illert's and other works, like those of the italian psysicists Michele Natteri and Francesco di Noto, from the Departments of Earth Sciences and from the Department of Mathematics and Application "R. Cacciopoli" of the University of Napoli, researching on the presence of the Fibonacci number in the String Theory, the conseguences and the physical implications, that you can see also here from other studies: http://www.scientificamerican.com/article/the-strangest-numbers-in-string-theory/

if Yuo would like to speak with us, or receive more References, we would be extremely delighted. Here we are speaking about Divulgation, and Public Knowledge, Journalism and Ethic of Progress, scientifically speaking and socially speaking. Thank you vesprolatuna 01:13 (UTC)

I stand by my edit summary, but given the extra space available here I would like to add that two of references in question are in International Journal of Physics and Astronomy published by Recent Science, listed as a predatory open access publisher by Beall's list, and in Hadronic Journal, the personal journal of notable fringe scientist Ruggero Santilli. Neither can be accepted as a reliable source here and their presence in this material (together with the shout-out to Santilli himself) makes it less credible, not more. —David Eppstein (talk) 01:00, 29 November 2015 (UTC)

barnstar

		The Original Barnstar
		For a helpfully thorough GA-review of Trevor Kincaid. LavaBaron (talk) 09:44, 30 November 2015 (UTC)

You're welcome! —David Eppstein (talk) 16:49, 30 November 2015 (UTC)

Thanks for participating

Thank you for your participation in the Women in Science Virtual Edit-a-thon, 8 to 29 November 2015, hosted by Women in Red together with Women scientists. It was held in parallel with a meet up at the New York Academy of Sciences on 22 November. In addition to improvements, we created well over 300 new articles. Your contributions are appreciated!

Hope you will also join us for the WiR Women in Religion Virtual Edit-a-thon from 5 to 15 December.--Ipigott (talk) 10:59, 2 December 2015 (UTC)

Wallis product

Would this be a better reference? Thanks!http://scitation.aip.org/content/aip/journal/jmp/56/11/10.1063/1.4930800 User:Correogsk (talk

Yes, but the question should really be: what coverage of this topic do you think should be added beyond what is already there at the end of the "derivation" section, which already uses this reference? Your new text didn't add much actual information to the article. —David Eppstein (talk) 23:01, 3 December 2015 (UTC)

Hi, David. Well,I'm not a mathematician, but it seems to me that the relevance of this discovery is the fact that it's the first time Wallis product is found outside/beyond the field of mathematics themselves. Wait for your view. Thanks! Correogsk or Gustavo (talk) 01:50, 4 December 2015 (UTC)

Yes, but what is added in your comment beyond what was already in the article on the exact same topic? —David Eppstein (talk) 03:12, 4 December 2015 (UTC)

Oh, my! I hadn't seen the issue about the hydrogen atom was already covered, sorry and thanks a lot, David! :) A Mexican hug!

Please

Aplique su conocimiento de topología conjuntista; definitivamente, entre un polígono simple y la circunferencia se puede establecer un homeomorfismo; y para que se distraiga vaya efectuando $1^{\sqrt{7}}$ — Preceding unsigned comment added by X2y3 (talk • contribs) 04:15, 11 December 2015 (UTC)

My Spanish isn't good enough to read this sort of technical writing without the assistance of Google translate. But the issue with your edits to Simple polygon wasn't their correctness; it was that they were written in Spanglish rather than English. —David Eppstein (talk) 04:22, 11 December 2015 (UTC)

Unit disk graph complexity

Hello, the reason for this is in the section "Computational complexity": the problem is whether a graph, given without geometry, can be represented as a unit disk graph. It is also present the Category:NP-complete problems, don't you see? --Horcrux92 (talk) 17:52, 11 December 2015 (UTC)

My feeling is that the category Category:Computational problems in graph theory should be reserved for articles that have a computational problem as their main topic (such as clique problem) rather than ones on something else that happen to mention complexity along the way. Everythiing (or at least everything in discrete mathematics) has an associated complexity; listing them all in the category would be too indiscriminate. And the fact that this one happens to be NP-complete doesn't make it any more or any less of a computational problem than something else with a polynomial time algorithm. —David Eppstein (talk) 17:56, 11 December 2015 (UTC)

Age of rock art at Padah-Lin Caves

Hi, you reverted my edit that described the art at Padah-Lin as 'Holocene'. The previous description of 'mesolithic and neolithic' is taken from reports of the site that are now out-dated. It is no longer accurate because 'mesolithic' is not a chronological period in Southeast Asian prehistory. It has not appeared in any scholarly literature of Southeast Asian archaeology for 30 years and has no definition as a culture-history phase in this region (I read, teach and write this literature). 'Mesolithic' is only meaningful in Europe and the Levant. On the other hand, 'Holocene' is a current and widely used term that refers to a well-defined period all around the world from 11,700 years before the year 2000 AD, up to the present (and so not 'uninformative', as you claim). The Holocene period includes the 'neolithic' period of Southeast Asia, but since the neolithic is not well defined for Myanmar, is it not a good choice to specify a time period. There is no direct evidence for the age of the art at Padah-Lin, so any claim about the age must be vague to properly communicate the lack of certainty about the age estimate. The terms 'mesolithic and neolithic' are almost meaningless for indicating a time period in this region (at best confusing), and their usage here reflects an awareness of the scholarly literature that is at least 30 years out of date. This is forgivable for the literature that was published in the 1960s, and scholars in Myanmar who have very limited access to the internet. But for everyone else, it's not a well-informed choice, so I hope we can agree to move on from 'mesolithic and neolithic' and use 'probably Holocene' instead. What do you think? Comtebenoit (talk) 10:59, 14 December 2015 (UTC)

I think that if you want to use a new date you should use a new source that states that date rather than changing the date but leaving the source of the sentence unchanged. I think holocene should not be capitalized. I also think "these artifacts date from the holocene" is almost completely uninformative because it's true for almost all human artifacts. It would be better to give an approximate range of millennia, because the holocene extends until today and presumably we know that the cave artifacts are older than that. —David Eppstein (talk) 16:56, 14 December 2015 (UTC)

I've checked the primary sources - I mean the report by the excavators. The art is not dated at all, and the word 'mesolithic' is not used to describe the art. To use the word 'Holocene' is not adding a new date, it's using the current technical vocabulary for the same dates. Using current technical terms reduces confusion and ambiguity. Readers of the scientific literature will know that Holocene is properly styled with a capital H because it's a proper noun (you can also see this in the wiki article). 'Holocene' spans almost exactly the periods indicated by the seven radiocarbon dates for this site. So it's an accurate and unproblematic label to describe the period of human activity at this site. To the non-archaeologist, it might seem that 'almost all human artifacts' come from the Holocene. However, there is also the 'Pleistocene', which spans 10k years BP to about 2 million years BP, and there are lot of artefacts in the world from that period also. There is also upper, middle and lower Holocene and Pleistocene, which are routinely used in the scientific literature to indicate greater chronological resolution. In this case, we don't have any greater resolution than 1750 years BP to 13,400 years BP (as reported in the publication by the excavators), so 'Holocene' is quite appropriate, or 'Upper Pleistocene and Holocene' would also be ok. I've also added a new reference for the dates, and some photos. — Preceding unsigned comment added by Comtebenoit (talk • contribs) 04:58, 15 December 2015 (UTC)

I'm happier seeing it spelled out as 1750 years BP to 13,400 years BP (or whatever other dating system you want to use): it's more precise (because it rules out more recent times) and also less WP:TECHNICAL. —David Eppstein (talk) 05:04, 15 December 2015 (UTC)

Ruggero Maria Santilli

Dear David, we do not understand what it needs to be done to consider a scientist a scientist, if, apart of the mathematical skills and the commercial and the practical experience, he've been awarded by so many prizes and recognitions. On his website there are pictures that demonstrate the recieving moments of the prizes. But we know this is kind of useless question with you. Anyway, we found the official source ofr the mediterranean prize, so we will add it.

Concerning Dr Leong Ying. There are not only pictures of them, but you can clearly see from the main page of Dr Ying theory of Twin Universe that his idea are completely in agrees with Dr Santilli's. Apart of this, there sis a video documentare (Reinassance of Cosmology) where Dr Ying speaks about Dr Santilli and in Santilli's website there are many pictures of the entire Princeton Gamma-Tech Instruments team, leaded by Dr Leong Ying, working with Dr. Santilli. At this point we conclude that it is absolutley not fair that more references than these have been asked. We ask that our contribute is manteined. If not, we will write personally to Dr YIng, maybe a direct declaration will be enough as a clear reference.

Thanks

[Vespro Latuna] 16 December 2015 01:27 (UTC) — Preceding unsigned comment added by Vespro Latuna (talk • contribs)

Opeyemi Enoch

Hi David,

I note that you reverted my edit of the Enoch biography page. A more correct history of Enoch's supposed proof would include the crucial role of BBC world service, where a journalist had read that Enoch had been awarded the prize. In turn the BBC (being a trusted source) was copied uncritically by other newspapers. Later the BBC, realizing their mistake, added a header in parentheses saying that the story was based on the assumption that the prize had been awarded.

The websites and blog calling the proof fake, a hoax, or plagiarized (or a Nigerian scam) are not reliable sources of anything. I'm not an expert in Wikipedia but I think there are very strict criteria about biographies of living people, and to say that a source says that someone is a hoaxer is a very serious thing to do. It is just not notable that some bloggers think that the proof is a hoax or is plagiarized, and it is a serious thing to commit to print.

It is clear that there is no proof; the discussion on the Riemann hypothesis talk page is all very responsible and clear about it. The fact that Enoch's university (or supposed university) has no information about his proof, or even about his existence, suggests so. Someone on the talk page (I do not know who) just said clearly that the issue is that although Enoch said that he has a proof, he has not posted one anywhere. This biography article could do the same. Otherwise it ought to, I think, be deleted.

Just on a basis of fairness, also, it is wrong for Wikipedia to repeat accusations of fraud etc which have not been established by any reliable source (and may well be false, there is a difference between being over-confident in your work and being a fraud, and one can interpret Ringos' public statements as trying to be responsible and admit that she may have mistakenly told Enoch in her conference that she understands his proof, and he may have misundersstood the fact that she does not represent the mathematical establishment).

Since you've taken the step of reverting my edit, how about changing the article to make it less like an accussation of intentional fraud on the part of Enoch.Createangelos (talk) 19:05, 20 December 2015 (UTC)

P.S. I don't know if you've seen Nigerian journalists' responses, but they think that the problem is that jealous western scholars are trying to block a valid proof, and that Enoch is a hero involved in a political battle. Such a notion could be really damaging to scholarship in general -- to the way that beginning scholars in China, India, Africa understand how scholarship is done, and also, for instance, the relative trustworthiness of business and science articles versus mathematics and philosophy articles.

In other words, this biography (which gives credibility to bloggers who caricature what good scholarship can be like) gives fuel to those who see scholarship as a power game, rather than as a game of trust or a search for meaningful belief.Createangelos (talk) 19:05, 20 December 2015 (UTC)

P.P.S. If you read a few of Enoch's earlier articles, they are bad but not terrible. They involve very complicated rewritings of the zeta function by trigonometric functions like sin and cosine, and refer to other articles where such equations are established.Createangelos (talk) 19:07, 20 December 2015 (UTC)

My preferred solution would be to just delete the article. There's not much to say besides "he doesn't have a proof, and the media blew it up". See my earlier prod. But the reason for my revert was that your version could easily be read as implying that he really does have a proof that happens not to be public yet. I don't think that's accurate and I don't think we should be implying it. —David Eppstein (talk) 19:50, 20 December 2015 (UTC)

Hmm we can recommend it for deletion, via the deletion log. Have you done that before, i.e. know how to do it?Createangelos (talk) 21:47, 20 December 2015 (UTC)

Ok, I have started a deletion discussion — see Wikipedia:Articles for deletion/Opeyemi Enoch. —David Eppstein (talk) 22:48, 20 December 2015 (UTC)

GA review for Du Friedefürst, Herr Jesu Christ, BWV 116

Hi David, I just did a GA review for the Bach cantata linked above. I think that it's close to passing subject to the revisions I listed in Talk:Du Friedefürst, Herr Jesu Christ, BWV 116/GA1, but it's been a long time since I did a GA review (2007?) so I'd love a second opinion on whether my assessment according to the criteria is likely to stand, particularly since there are two other similar cantatas by the same author that I would then continue to review. Thank you! -- Michael Scott Cuthbert (talk) 17:40, 23 December 2015 (UTC)

78.26's RFA Appreciation award

	The 78.26 RFA Appreciation award
	Thank you for the participation and support at my RFA. It is truly appreciated. I hope to be of further help around here, and if you see me doing something dumb, you know where to find me. Again, I thank you. 78.26 (spin me / revolutions) 02:11, 24 December 2015 (UTC)

Your GA nomination of Binary logarithm

Hi there, I'm pleased to inform you that I've begun reviewing the article Binary logarithm you nominated for GA-status according to the criteria. This process may take up to 7 days. Feel free to contact me with any questions or comments you might have during this period. Message delivered by Legobot, on behalf of Jfhutson -- Jfhutson (talk) 21:40, 28 December 2015 (UTC)

Revert of Complete quadrangle intro

I think you were mistaken with this revert. I said "exactly two points", which means two and only two points. And regardless of whether you accept that or not, it's better than the clumsy brain twisted version that you reverted back to. Furthermore, why a revert? Why not correct the error you saw instead of bulldozing my hard work? Zephalis (talk) 03:25, 30 December 2015 (UTC)

My objection was to the part where you got rid of the restriction that the four points have no three on a line. That part was important. Your phrasing "where only two no three of which pass through the same point" is also very clumsy. —David Eppstein (talk) 04:07, 30 December 2015 (UTC)

"where only two no three of which pass through the same point" was a typo, of which could've been easily fixed. There were actually traces of two other versions of the statements that I overlooked because I was quite tired by time I finished.

As for what you say about the "four points hav[ing] no three [points] on a line", I stated that it had "exactly two" points, which covers that there isn't three points. I already said this in my first statement to you as well.

So again, I ask you, why don't you just correct it and not do a revert? I took the time to rephrase it because it's difficult to make sense of the original and I had to go at it piece by piece to get the idea into my head. Even knowing what it is now, the original phrasing is still very difficult to comprehend. I know it's difficult to phrase in a simple, but complete way because it took me a couple hours to phrase it the way I had it, especially since I was also trying to mirror the two definitions so they could be better understood as a whole. --Zephalis (talk) 05:14, 4 January 2016 (UTC)

Deleted section from Fermat`s Last Theorem

Dear Prof. Eppstein. What is the problem with the Appendix where I wanted to share my new elementary research results about the subject ? How do you like these ideas ? Ok now I understood why it was deleted but it does not change the beauty of this result does it ? Happy New Year: White Tiger (talk) 19:07, 30 December 2015 (UTC)

Please see WP:NOR regarding original research and Wikipedia. There are lots of places on the web to share new research results; Wikipedia isn't one of them. —David Eppstein (talk) 02:49, 31 December 2015 (UTC)

2016

	Happy New Year 2016!
	Did you know ... that back in 1885, Wikipedia editors wrote Good Articles with axes, hammers and chisels? Thank you for your contributions to this encyclopedia using 21st century technology. I hope you don't get any unneccessary blisters.    – Cullen328 Let's discuss it 01:25, 31 December 2015 (UTC)

Happy New Year, David Eppstein!

Happy New Year!

David Eppstein,
Have a prosperous, productive and enjoyable New Year, and thanks for your contributions to Wikipedia. Poepkop (talk) 16:08, 1 January 2016 (UTC)

Spread the WikiLove; use {{subst:Happy New Year 2016}} to send this message

.

Your GA nomination of Reuleaux triangle

The article Reuleaux triangle you nominated as a good article has passed ; see Talk:Reuleaux triangle for comments about the article. Well done! If the article has not already been on the main page as an "In the news" or "Did you know" item, you can nominate it to appear in Did you know. Message delivered by Legobot, on behalf of Spinningspark -- Spinningspark (talk) 22:42, 2 January 2016 (UTC)

Your GA nomination of Binary logarithm

The article Binary logarithm you nominated as a good article has passed ; see Talk:Binary logarithm for comments about the article. Well done! If the article has not already been on the main page as an "In the news" or "Did you know" item, you can nominate it to appear in Did you know. Message delivered by Legobot, on behalf of Jfhutson -- Jfhutson (talk) 22:43, 2 January 2016 (UTC)

Hi Ed, I got an email notification from you

but I didn't get an email. Do you think you could resend it? Thanks :-) Serendi^podous 08:16, 3 January 2016 (UTC)

@Serendipodous: I have no idea what you're talking about, and my name's not Ed. You sure you left this message in the right place? —David Eppstein (talk) 08:22, 3 January 2016 (UTC)

Oh, sorry. Clicked the wrong talk page I think. :-) Serendi^podous 08:33, 3 January 2016 (UTC)

Your GA nomination of Stars (M. C. Escher)

Hi there, I'm pleased to inform you that I've begun reviewing the article Stars (M. C. Escher) you nominated for GA-status according to the criteria. This process may take up to 7 days. Feel free to contact me with any questions or comments you might have during this period. Message delivered by Legobot, on behalf of Dr. Blofeld -- Dr. Blofeld (talk) 13:00, 4 January 2016 (UTC)

A very fine article, one of the most professional I've read in a long time. You being a computer science professor explains it I guess. Keep up the terrific work.♦ Dr. Blofeld 13:12, 4 January 2016 (UTC)

Thanks! —David Eppstein (talk) 18:30, 5 January 2016 (UTC)

consider

dear first consider if it is not reliable mention the reason without reason every edit you delete why...... lot people are here for editing wikipedia. — Preceding unsigned comment added by HannuMannu (talk • contribs)

Context: two reverts to Square (algebra) and Symmetry, and a comment on Wikipedia:Articles for deletion/Books written in unconventional ways. HannuMannu was later blocked for (among other things) edit-warring on the same edits to Square and Symmetry, which were reverted by two other editors. —David Eppstein (talk) 18:25, 5 January 2016 (UTC)

DYK for Binary logarithm

Cas Liber (talk · contribs) 00:02, 6 January 2016 (UTC)

Recently removed "linkspam"

Hello professor!

You recently undoed my edit with the change description "linkspam", where I linked to a website where I implemented the recursive maze-solving algorithm as written in the wikipedia article. Two years ago, I added the recursive algorithm to the "maze solving algorithm" page (https://en.wikipedia.org/wiki/Maze_solving_algorithm#Recursive_algorithm), with sample code in Java. I recently learned javascript, and was able to recreate the same algorithm visually, and I thought linking to it as a sample implementation was appropriate. Please let me know why what I did was not allowed, and if there is any other way to provide readers with a better understanding of the recursive algorithm.

Thanks in advance, Ofek Gila!

Ofek Gila (talk) 04:02, 7 January 2016 (UTC)

See WP:EL for what links are appropriate or not, and WP:COI for adding links to resources that you created. —David Eppstein (talk) 04:35, 7 January 2016 (UTC)

Cuckoo hashing

In reference to:

https://en.wikipedia.org/w/index.php?title=Cuckoo_hashing&oldid=prev&diff=698589296

"Cuckoo hashing is not as fast as quadratic probing in general-purpose hashing applications on most modern processors. However, cuckoo hashing may outperform the alternatives in various special cases, when there are other constraints on the design of the data structure."

(Undid revision 698587282 by Aaron Will Claims like this cannot be included unless they are backed up by reliable sources. Also the studies I've seen show linear probing as fastest, not quadratic probing.)

Quadratic probing is just a generalization of linear probing; linear probing *is* quadratic probing. If the hash function is perfectly uniform, quadratic probing has no benefit; in the academic references linked from the page, the authors are typically just using random data, and side-stepping the hash function itself. So they will just compare to linear probing as representative of both linear and quadratic, because there's no difference. But perfectly uniform hash functions are slow; faster compromise hash functions that are actually used in practice are prone to 'funneling,' and quadratic probing is the mitigation. So a real-world hash table will always use quadratic probing, not linear probing; but they're approximately the same thing. But I think it sounds goofy to say, without qualification, that "linear" is faster, because no high performance table is using linear probing, because it gives poor results with fast hash functions.

This is not a novel or controversial result, as far as I'm aware. It's been well-known for decades, and I'm sure it's discussed more carefully on the main hash table page.

I am happy to word this any way you want. But the article is misleading in its current state without containing some form of this remark, making irrelevant claims about how much faster it is than chaining, which is sort of like saying how much faster Shell sort is than bubble sort. I'd honestly be much happier if, rather than reverting my edit, you reworded it to address your concern. What do you think? Aaron Will (talk) 20:49, 7 January 2016 (UTC)

The studies I've seen have been based on reasonable quality hash functions, but with that caveat they show that linear probing is much better than other probing strategies, because of its improved locality of reference. Anyway, you're asking the wrong question. What I think about hashing is not important. What you need to do before inserting any such comparison is to find publications that actually address this issue, and report what they say about it, rather than putting your own editorializations into Wikipedia without sourcing. —David Eppstein (talk) 21:39, 7 January 2016 (UTC)

PS Another consideration is that both cuckoo hashing and linear probing allow for fast deletions; I don't know how to do this easily for quadratic probing. As for the claim that speed requires the use of a bad hash function, and an overly complicated probing sequence to make up for the bad hash function: I don't actually believe this. See e.g. http://arxiv.org/abs/1503.03465 for a pretty good hash function (I'm not sure whether good enough for linear probing, but better than commonly used bad ones) that is also faster than the commonly used bad hash functions. Again, though, what I believe isn't important, it's what the reliable sources say. But we definitely shouldn't say that it's not possible to have hash functions that are both high quality and fast, because the sources contradict this. —David Eppstein (talk) 23:12, 7 January 2016 (UTC)

Look I just want to fix the article. I don't have a cite. What about Primary clustering and Quadratic probing, which basically describe this problem and why quadratic probing helps, also mostly lacking cites? Can we just cite that? Linear probing and quadratic probing, for all purposes of this discussion, are the same thing. Linear probing counts using an, and quadratic probing counts using an + bn^2. You say 'good' and 'bad' hash functions, but the reality is that any performance hash function over general purpose data is a compromise.

'Good' hash functions typically don't have really bad funneling, but they still tend to have some degree of clustering for hashing inputs that are very related--this being the normal case in practice. And check out the paper you cited; they admit that the version they're actually doing speed tests on fails the avalanche test, a catastrophic failure for a practical hash function, and that a modification is necessary. But just having good 'avalanche' still doesn't guarantee you don't have clusters; just stealing and tacking on murmur3's mixing step isn't going to be enough to magically give them uniform output for related keys, even if it does make the test pass. The other thing to keep in mind is that, in practical implementations, quadratic isn't slower than linear, so there's never any reason to implement purely linear probing unless you don't really care about performance, or you are on a specialized platform that doesn't have multiplication, or something. Finally quadratic probing generally is only counts differently from linear after we've had a couple collisions in a row, which should already be an outlier case--otherwise something is wrong and our hash table is going to go way too slow. This isn't some novel result I just came up with; like I said, it's well-known, and any high-performance hash table implementation has at least this level of sophistication. (Ironically I checked my language's library just now, and it's using chained buckets, so it's not even participating in this conversation.)

I'm frustrated because I don't really like the way you're engaging me here. I don't think you should be reverting this statement merely because it's uncited, especially since you seem to concede that it's more-or-less true, modulo the foregoing distinction between linear and quadratic, which isn't really the key point I'm trying to make; my point is that Cuckoo hashing is not that fast compared to the pre-existing state-of-the-art. Please see WP:ROWN for why I feel this way. If I had some other general term for cache-friendly open addressing scheme, I'd use it, to avoid your concerns about 'quadratic,' but as far as I'm aware, there really aren't any other alternatives. Cache lines aren't big enough for there to be too many different strategies here; but quadratic probing is a generalization of all of them, as far as I'm aware. Aaron Will (talk) 03:59, 12 January 2016 (UTC)

A possibly interesting reference (though I'm not convinced it passes Wikipedia's tests for reliability): http://rcoh.me/pyhash.pdf. It claims that replacing Python's built-in dictionary with linear probing and tabulation hashing led to significant speedups on test data and smaller but still nonzero speedups on more realistic data. I'm also aware of recent work in computer security in which using a hash table that can be made to have collisions is viewed as a security violation (because it can lead to denial of service attacks and back door communication channels). But we really really can't take your personal experience as a source, and using another Wikipedia article for a source is no better. If those other articles are making similar assertions without proper sourcing then they need to be fixed. —David Eppstein (talk) 04:33, 12 January 2016 (UTC)

Your GA nomination of Stars (M. C. Escher)

The article Stars (M. C. Escher) you nominated as a good article has passed ; see Talk:Stars (M. C. Escher) for comments about the article. Well done! If the article has not already been on the main page as an "In the news" or "Did you know" item, you can nominate it to appear in Did you know. Message delivered by Legobot, on behalf of Dr. Blofeld -- Dr. Blofeld (talk) 23:21, 8 January 2016 (UTC)

Cliques = connected components in graph of equivalence relation.

Hi, I'm the foolish bunny who perpetrated this change you reverted about the connection between the maximal cliques and connected components in the graph representing an equivalence relation. I think of the clique as a set of vertices with a property (distinct vertices connected) and the connected component as a graph (set of vertices + set of edges). Even taking a clique as a graph, it still doesn't seem to be equal to a connected component: each connected component has a loop on every vertex due to the reflexivity of the equivalence relation; no such loops are implied by the clique. Could you explain in what way "the maximal cliques *are* the connected components"? Frentos (talk) 11:23, 10 January 2016 (UTC) PS As a matter of form, should I have created a discussion on the talk page for equivalence classes and just left a comment here directing you to the discussion? Frentos (talk) 11:30, 10 January 2016 (UTC)

If you think of a clique as a subgraph rather than a set of vertices, and ignore the loops, then the maximal cliques are exactly the connected components. Your wording made it sound like there could be multiple clques per connected component, which I think is misleading. Also, there is no difference between "maximal cliques of the connected components of G" and "maximal cliques of G", so your wording was unnecessarily indirect. —David Eppstein (talk) 16:31, 10 January 2016 (UTC)

I agree my replacing "forming" with "of" was misleading; thank you for reverting it. The existing wording, "maximal cliques forming the connected components of the graph" makes it sound like the maximal cliques (as subgraphs) are the connected components when they are proper subgraphs of the connected components, which I think is misleading. The reference (Devlin, p. 123) makes no mention of cliques, but explicitly notes reflexivity of the connected components, which cliques lack. It would be clumsy to add a qualification about adding or ignoring loops to make the statement correct; perhaps it would be clearer and more concise to remove the reference to cliques and say the equivalence classes are represented by [the vertex sets of] the connected components? — Frentos (talk) 20:38, 10 January 2016 (UTC)

Maybe, but I think it's important that these components are complete+self-loops, rather than just being any kind of connected graph. —David Eppstein (talk) 21:31, 10 January 2016 (UTC)

The correspondences I can think of between the equivalence relation ~ on the set X and the graph as described are:

1. Each element of X corresponds to a vertex (by construction)
2. Each s~t corresponds to an edge (by construction)
3. Each equivalence class corresponds to the vertex set of a connected component
4. The disjointedness of equivalence classes corresponds to the disjointedness of connected components
5. The reflexivity of ~ corresponds to the loop on each vertex
6. The symmetry of ~ corresponds to either no edge or 1 undirected edge between any distinct pair of vertices
7. The transitivity of ~ corresponds directly to any two adjacent edges being part of a triangle and indirectly to completeness of each connected component
8. The property that any two distinct elements of the same equivalence class are related by ~ corresponds to the completeness of a connected component
9. The property that any two elements of the same equivalence class are related by ~ corresponds to the completeness of a connected component + the loops on each vertex

1& 2 are redundant. The article is trying to say 3 (which implies 4) and mention the graph part of 7 (or 8 or 9) in passing in just one sentence. Maybe split it into two sentences: one for the equivalence classes and one for the reflexivity<=>loops and transitivity<=>component completeness? A simple diagram? I'd be happy to knock up a simple undirected diagram ala Devlin. Frentos (talk) 01:24, 11 January 2016 (UTC)

Tetrahedron

Stop changing my edits to tetrahedron Ghostasylum (talk) 16:34, 11 January 2016 (UTC)

Directed Acyclic Graph updates

Professor Eppstein, you asked whether a Bitcoin block processes data. A Bitcoin block is a group of transactions confirmed by the world's most powerful computer network (See Forbes article). The network processes financial transactions through the blockchain as a linked list. This leads to a competitive race using proof-of-work to verify transactions were not double-spent, something only previously possible with a clearing house or other financial trusted third party. There has been considerable talk around using DAG data structures in crypto currencies, particularly Bitcoin, rather than a linear linked list. This adds complexity to the system, but reduces confirmation time by orders of magnitude with network latency and CPU power become the only bottlenecks. At this time, DAGs are only in the proof of concept stage, but it is a potentially revolutionary use of the data structure.

Perhaps this use case belongs in another section, but I believe that prior to the discussion of DAG usage in Bitcoin, many people who are not data scientists, myself included, had never heard of this data structure. — Preceding unsigned comment added by Mfactor (talk • contribs) 16:26, 15 January 2016 (UTC)