User talk:David Eppstein/2013d

Pasch's theorem

Hi David,

Thanks for the addition on the Foundations of geometry page - but I do have a question about it. Do you really know of any reference for "Pasch's theorem" independent of WP and the Mathworld page (neither of which has a reference)? I've been trying to track down a good reference for this for about a month now without success. Outside of our page and the Mathworld page (one of which was certainly copied from the other) almost all the Google scholar references confound Pasch's theorem with Pasch's axiom (which makes sense from a modern perspective ... if you don't start with Hilbert's axioms, Pasch's axiom becomes a theorem). Until quite recently, our page Hilbert's axioms implied that Pasch's theorem was an old axiom of Hilbert about the ordering of four points on a line which was shown to be provable by E.H. Moore and R.L. Moore (no relation) and removed by Hilbert. I find this explanation very plausible, but almost certainly OR by one of our editors. The only other reference that I have found is by Pambuccian (an expert on ordered geometry) who refers to the statement that a line cannot intersect all three sides of a triangle (internally) as Pasch's theorem. While there are still a couple of sources that I don't own which I need to look at, I am beginning to think that I won't be able to resolve this issue ... there may not be any statement which has a claim to be called "Pasch's theorem". Any light you can throw on this would be appreciated. Bill Cherowitzo (talk) 03:12, 3 October 2013 (UTC)

Sorry, no, I don't have any hidden references up my sleeve. Do you think the article has big enough OR problems that it should be prodded? —David Eppstein (talk) 03:33, 3 October 2013 (UTC)

Oh well ;^(. I've thought of prodding it to scare up a reference, but as I said, I still need to try a couple of standard references before I'd be willing to go that far. The OR problem was on a different page, and I've taken care of that problem already. Thanks. Bill Cherowitzo (talk) 04:35, 3 October 2013 (UTC)

Amanda Palmer

I have added 3 citations, each from a different country (one is a news citation from The Guardian newspaper). Wouldn't it be better to take it to the Talk page, rather than enacting a sweeping reversion in a proprietary manner?--Soulparadox (talk) 17:14, 5 October 2013 (UTC)

See WP:BRD. Reversion is the middle step. Taking it to the talk page is the third step. Re-adding your bold changes is not in the list. —David Eppstein (talk) 19:51, 5 October 2013 (UTC)

Soulparadox:

1. You should have taken this to Talk:Amanda Palmer instead of here. (If in a day or more, you don't get a reply, then post a link on a user's talk page to the article talk page).
2. I concur with David Epstein about WP:BRD.
3. Three editors have now reverted your edit about the open letters. They each cited reasons support by Wikipedia's core principles, policies, and guidelines. You have yet to make any argument that does so. The consensus is for not including anything about the open letters in the article. If you want to try and change that consensus, conduct the discussion on Talk:Amanda Palmer.
4. Before a dead link is deleted, a good faith effort should be made to find it in the available web archives. (WP:LINKROT saids otherwise.) Dead links are generally not deleted. Editors can repair them. Prevention is recommended. Please read WP:LINKROT. WP:BRD applies here too.

David Epstein: Please forgive me for adding to the discussion here on your talk page. Thanks. Lentower (talk) 20:11, 5 October 2013 (UTC)

Yes Mr. Epstein, please also forgive me for my conduct on Wikipedia. I sincerely thank you for your mercy thus far sir. I also just need to clarify that this statement is not accurate: "They each cited reasons support by Wikipedia's core principles, policies, and guidelines." Also, sir, I have added a section to the Personal section that is extracted from the aforementioned blog post, so please feel free to revert or revise as you see fit sir. Thank you kindly for your assistance in this matter. I understand the importance of consensus and will also paste this into the Talk page.--Soulparadox (talk) 10:37, 6 October 2013 (UTC)

Just to clarify, I added this segment, as I was concerned that it was confused with the Solo Career addition that was the main subject of discussion. The edit were completed in the same turn. Kind regards,--Soulparadox (talk) 10:41, 6 October 2013 (UTC)

Literature on Stomachion/Ostomachion/Loculus

Might I just enquire how much of the literature on these topics you have actually read? The paragraph flagged conflates three literary traditions, plus etymology, that it is surely open to the challenge of original research, without more careful rewriting; it is a matter of presumption that the intent of authors in these different traditions that are by no means contemporary is the same and in Wikipedia we are not supposed to read into authors cited more than their texts sustain. Of course, we can cite translators or commentators who have done that, but without reading more into them than is there.

For instance, have you actually read the paper of Netz, Acerbi and Wilson of 2007 that is flagged on the talk page and has recently appeared in the references? In it we find the figure the Archimedes of the Stomachion fragment is investigating, as already given by Heiberg and Dijksterhuis, and about which there seems general agreement. As it is so generally agreed upon, and we can cite all these three sources, surely it is worthy of inclusion in the Wikipedia entry? The only problem for the article as it stands is that it does not immediately suggest a dissection problem.

Again, have you read the contributions of Richard Dixon Oldham, FRS, in 1926 to Nature, to The New York Times or to Popular Science Magazine? Surely, the caption the first figure shown to the left only makes sense if we have in mind Oldham's attempted reconciliation of Suter's German translation of the unpointed Arabic text and the Greek fragment in the Palimpsest?

Have you read H. J. Roses's Handbook of Greek Literature (1934), pp. 37--38 in which he alerts the classicists to Oldham's attempted reconciliation? Did you notice that Giovanni Vacca and Giuseppe Peano took note of Oldham's interpretation, too, as shown in the anniversary volume Lo spirito creativo e leggro: Giuseppe Peano (1858-1932), matematico e maestro (2008)? Staying with the Italian, have you seen Giuseppe Morelli's Lo Stomachion di Archimede nelle testimonianze antiche in Bollettino di storia scienze matematiche for 2007, which gives a comprehensive survey of the classical sources and allusions, although missing reference to Oldham?

Given your scholarship and learning, the presumption is that you have, although I freely admit that this is original research on my part. The mystery then is why you might think the article can stand as it does, without more careful delineation of what each tradition is about and without more detailed references.

There is no dispute that two of these traditions, the Greek and the Arabic, deal with mathematical problems. The large section that you have excised in toto seemed to me to have been written as a standing invitation for rewriting; and that seems (to me) to have arisen because of the divergence between Netz' popular writings and public promotional appearances and his more narrowly scholarly research with Acerbi and Wilson which has not been so easy to obtain. I put it to you that, to strip it out is not only original research by censorship, but also original research by default, in that it leaves what remains dangling.

Why would an experienced and sensitive editor of Wikipedia with your great scholarship and learning do that? — Preceding unsigned comment added by 129.180.1.224 (talk) 21:49, 5 October 2013 (UTC)

Edit-a-thons at UC Riverside

The UCR Libraries are hosting three edit-a-thons focusing on their great special collections (science fiction, water resources, the Inland Empire and more) on Oct. 12, 2013, Oct. 26, 2013, and Nov. 23, 2013. Please participate if you can! Details and signup here. All are welcome, new and experienced editors alike! -- phoebe / (talk to me) 04:10, 8 October 2013 (UTC)

Talk:Hal_Abelson#Proposed_consensus

Wait a few more days for others to reply. Some editors might be on a three day weekend. Some editors only edit from work. Lentower (talk) 22:38, 14 October 2013 (UTC)

Sure, but I don't see any harm in making changes now and then making them again if others weigh in differently. We haven't set up a formal RFC with a set time limit. Frankly, I see your reversion as destructive and not contributing to a better encyclopedia — I made a lot of changes to the article, most of which were unrelated to whether Harvey is primary and are not under consideration in the talk page discussion, and you reverted them all blindly without considering their merits. Please reconsider your harmful actions. —David Eppstein (talk) 22:58, 14 October 2013 (UTC)

Writing Template:JctCA until Lua Jct ready

Your suggestion to develop both a Lua version of {Jct} as well as writing a California variation, as Template:JctCA, was correct. In fact, the actual performance tests proved {JctCA} was 25x times faster than {Jct}, to reformat a large junction/exit table about twice(!) as fast. Only a few road pages would need a faster {JctXX} template. However, some other editors are threatening to oppose use of the 25x faster template, so actual progress will most likely grind to a halt. In cases like this, I typically focus on other activities which do not involve so many disputes. My general rule of thumb is: "Wikipedia is 10% information, and 90% deformation" as to expect a simple problem to become 10x harder when disputes occur. I think there would need to be template-improvement guideline to mandate the use of "quick templates" which improve performance in severe cases. For the past 4 years, I have met similar resistance to improved templates, and the result is often wp:TfD deletion of the faster templates, even with new features also discarded in the deleted variation. In fact, after I carefully converted the wp:CS1 cite templates to Lua (with hundreds of parameter options), then the no-progress nightmare began again, this time opposing major improvements to the Lua variation. Jimbo himself has advised people to allow faster experimental templates, and I think it would require a mandate from the WMF managers to require people to accept faster templates and not drag templates to deletion (in some cases, repeating the TfD 4 times until wp:forum-shopping finally reached a delete decision). I just mention this to warn of how progress is thwarted in Wikipedia. I really wish Jimbo would accept a one-year job as Director of the Foundation, and then set "90" new official rules for how wiki projects would allow innovation, accept faster templates, appoint temporary admins, and hide explicit content (image categories) for children of concerned parents, but unfortunately, he is too busy leading other companies and remains a mere "admin" and volunteer editor who refrains from using his powers to implement his dozens of clever ideas to improve WP. At least it is fascinating to see how solutions could have been used to solve many irritating problems. -Wikid77 (talk) 05:12, 15 October 2013 (UTC)

Re: "In cases like this, I typically focus on other activities which do not involve so many disputes." I hear you on that. I don't always do that myself, but picking your battles and finding parts of the encyclopedia with better cost/benefit for your energy sounds like a good strategy to me. In the meantime the Highway 1 article will stay uneditable, I guess... —David Eppstein (talk) 05:38, 15 October 2013 (UTC)

Remind people to try section-edit of roads, for each section separately, then the edit-Save will just be a timeout warning but still saves the whole page. Meanwhile, I have expanded {JctCA} to begin to handle any U.S. state twice as fast, in testing New York roads, by getting state names from "state=xx" with quick Template:US_State_Abbrev (about 200-per-second). The more we know about the complex {Jct} options, then the better to create a Lua-based version of {Jct} some day. It took over 8 months to rewrite the major wp:CS1 cite templates into Lua, after creating a quick markup variation similar to {JctCA}, but once the Lua module started producing similar results to {cite_web}, then several people helped to test the results and made suggestions for fixes. -Wikid77 (talk) 17:15, 15 October 2013 (UTC)

Revert on my talk

Thanks I'm sure that this edit was well-intentioned but I like to keep all comments on my talk page, including ones which are spam or outrageous (not that this one is.) —Justin (koavf)❤T☮C☺M☯ 17:41, 20 October 2013 (UTC)

Sorry, I was doing a mass-rollback of Yambaram (talk · contribs)'s edits (recklessly adding Jewish categories to WP:BLP articles of people who had neither self-identified as Jewish nor were documented as being Jewish) and your talk page got caught up in it. Feel free to restore the comment. —David Eppstein (talk) 17:45, 20 October 2013 (UTC)

David Eppstein, I think the mass rollback you did was unacceptable and inappropriate. Never mind your huge reversion negatively affected pages like Koavf's talk page, but this rollback deleted the work of about 50 other articles in which I sourced and added categories and content perfectly fine. Was this supposed to be a collective punishment? I didn't even do anything recklessly, and these kinds of categories can be found on nearly every Wikipedia article. Every person for which I added a "Jewish category" is in fact Jewish. Richard Karp, who you pointed out on my talk page, is 100% Jewish, as stated in this extensive and documented list and in the article List of Jewish American computer scientists. I ask that you revert this massive undo and let me review my recent changes, or you could to do this too, rather than deleting hours of dedicated work in one click. -Yambaram (talk) 18:47, 20 October 2013 (UTC)

It was supposed to be making *you* do the work of figuring out which of your edits were properly sourced and relevant to the subjects and which were not, rather than forcing someone else to take that effort. And as for Karp and others of your edits that I found, unless the subject has self-identified as Jewish and the information is properly sourced in the text of the article, it is absolutely inappropriate to list them as Jewish here. Karp should probably be removed from List of Jewish American computer scientists unless relevant subject-specific sources can be found and added to his article. The jinfo list you give is useless for this purpose, as it provides no documentation of its inclusion of Karp and its footnotes attest to its indiscriminate labeling (according to ancestry rather than self-identification). —David Eppstein (talk) 19:02, 20 October 2013 (UTC)

David, please note, while I do insist on proper sourcing for the list, and have been quite strict about removing unsourced names, there is no requirement that the individuals "self-identify" as Jewish, only that they be identified by WP:RS as Jewish. Since "Jewish" is not a purely religious designation, but also an ethnic one, WP:BLPCAT does not apply to Jewish lists. Jayjg ^(talk) 20:47, 20 October 2013 (UTC)

I think this reasoning is specious and wrong. "Jewish" is both a religious and ethnic category, and either its religious and ethnic meanings should clearly be distinguished from each other (e.g. by renaming the list to avoid ambiguity) or it should be held to the higher of the standards for these two types of categories. —David Eppstein (talk) 21:00, 20 October 2013 (UTC)

You may think "this reasoning is specious and wrong", but neither policy nor Wikipedia history support your assertion. For better or worse, Jews are an ethnoreligious group, and therefore the "religious and ethnic meanings" cannot "clearly be distinguished from each other" - not by academics, not by Jews themselves, and therefore certainly not by Wikipedia editors. That's why we end up having to rely on what WP:RS say on the topic. Jayjg ^(talk) 22:57, 20 October 2013 (UTC)

Well said. I could be a religious or an atheist Jew, or even a self-hating one, but it'll not change who I am by blood/ethnicity. Just like an American-born Asian is an Asian, even if he or she gets an eye surgery and doesn't speak their native language. Yes, silly examples, I know, but this issue really does come down to WP:RS. I just want to know, will this rollback be reverted or should I spend some time going one by one and fixing what's needed? -Yambaram (talk) 23:22, 20 October 2013 (UTC)

The whole point of it was to make you go through them one by one, so I'm not going to reverse that. And I consider "self-hating Jew" to be quite an offensive term, one you probably shouldn't throw around so casually (and certainly one that should not be used on a biographical article of someone who has not publicly self-identified with that term). —David Eppstein (talk) 23:33, 20 October 2013 (UTC)

This is rough justice, but okay I'll do it now. That term which you think is offensive obviously wasn't meant to be an insult to anyone. -Yambaram (talk) 09:38, 21 October 2013 (UTC)

Yambaram, if you do add people to the list, please ensure that you add them in alphabetical orders (the list is alphabetized), and please ensure that the sources are reliable. simpletorember.com, for example, would not qualify as reliable for this purpose. Jayjg ^(talk) 20:47, 20 October 2013 (UTC)

Jayjg, I appreciate your input. I was actually about to say that Jews are also an ethnic race but forgot (see who is a Jew?). I'll be more careful with the sources I use in the future (it's hard to decide because often times some websites seem legitimate but are still considered unreliable). David, I personally doubt your opinion on how and when to use "Jewish categories" and Jews on lists, but you're an admit and so if you insist that I review all your 50 revisions then I'll just do it, I don't want to argue. Yambaram (talk) 21:14, 20 October 2013 (UTC)

OK Yambaram, but you simply added the names back to the list as before; same unreliable sources, even individuals who are clearly not Jews, and none in alphabetical order. Please fix that. Jayjg ^(talk) 23:58, 23 October 2013 (UTC)

Statistica (journal)

Hi, could you perhaps have a look at this journal? It's been around for over 80 years, so I'm surprised that it doesn't seem to be indexed in any database that I have access to (and they don't mention any on their website either). However, I don't have access to mathematics/statistics-specific databases, so perhaps you can find something? Thanks. --Randykitty (talk) 13:13, 21 October 2013 (UTC)

Request edit template

Note at the end of the documentation for the {{Request edit}} template, there is a link to Template:Request edit/COIinstructions#Current requested edits, which looks like a bot-maintained list of pending requested edits. isaacl (talk) 01:10, 22 October 2013 (UTC)

Discussion of interest

A discussion you may be interested in is this RFC, a proposal to make the second comma in a date/place optional. United States Man (talk) 05:44, 27 October 2013 (UTC)

Books and Bytes: The Wikipedia Library Newsletter

Books and Bytes

Volume 1, Issue 1, October 2013

by The Interior (talk · contribs), Ocaasi (talk · contribs)

Greetings Wikipedia Library members! Welcome to the inaugural edition of Books and Bytes, TWL’s monthly newsletter. We're sending you the first edition of this opt-in newsletter, because you signed up, or applied for a free research account: HighBeam, Credo, Questia, JSTOR, or Cochrane. To receive future updates of Books and Bytes, please add your name to the subscriber's list. There's lots of news this month for the Wikipedia Library, including new accounts, upcoming events, and new ways to get involved...

New positions: Sign up to be a Wikipedia Visiting Scholar, or a Volunteer Wikipedia Librarian

Wikipedia Loves Libraries: Off to a roaring start this fall in the United States: 29 events are planned or have been hosted.

New subscription donations: Cochrane round 2; HighBeam round 8; Questia round 4... Can we partner with NY Times and Lexis-Nexis??

New ideas: OCLC innovations in the works; VisualEditor Reference Dialog Workshop; a photo contest idea emerges

News from the library world: Wikipedian joins the National Archives full time; the Getty Museum releases 4,500 images; CERN goes CC-BY

Announcing WikiProject Open: WikiProject Open kicked off in October, with several brainstorming and co-working sessions

New ways to get involved: Visiting scholar requirements; subject guides; room for library expansion and exploration

Read the full newsletter

Thanks for reading! All future newsletters will be opt-in only. Have an item for the next issue? Leave a note for the editor on the Suggestions page. --The Interior 21:30, 27 October 2013 (UTC)

A barnstar for you!

	The Anti-Vandalism Barnstar
	For alerting the community at Wikipedia:Articles for deletion/Danielle Vanzura. Bearian (talk) 17:24, 29 October 2013 (UTC)

Thanks! —David Eppstein (talk) 17:39, 29 October 2013 (UTC)

Talkback

Hello, David Eppstein. You have new messages at Northamerica1000's talk page.
Message added 20:57, 30 October 2013 (UTC). You can remove this notice at any time by removing the {{Talkback}} or {{Tb}} template.

Northamerica1000^(talk) 20:57, 30 October 2013 (UTC)
Hello. You have a new message at User talk:Northamerica1000's talk page. Message added by Northamerica1000^(talk) 23:38, 30 October 2013 (UTC).

A barnstar for you

		The Food Barnstar
		Thanks for creating Liguria Bakery, and for improving Wikipedia's coverage of business-, food- and California-related topics. Northamerica1000(talk) 09:48, 2 November 2013 (UTC)

You're welcome! I haven't actually even been to that bakery, so I'll have to try it some time when I'm in SF. —David Eppstein (talk) 15:36, 2 November 2013 (UTC)

Nitza Davidovich

Hi David, I saw you deleted this article for lack of sources. I just re-uploaded it with sources. Please contact me if there are any issues. Thanks and have a nice day, Happy138 (talk) 07:12, 5 November 2013 (UTC)

I think you misunderstand. What we need is not a list of all things written by her (that would be a curriculum vitae, and is very far from being an encyclopedia article). What we need is sources *about* her, written and published by other people. —David Eppstein (talk) 07:22, 5 November 2013 (UTC)

MOS:COMMA

You recently contributed to a discussion at Wikipedia talk:Naming conventions (geographic names) § Commas in metro areas. Following a recent related RFC on the wording used at MOS:COMMA in relation to geographic names, a new wording has gathered some support and I have opened a new RFC at Wikipedia talk:Manual of Style § RFC: Proposed amendment to MOS:COMMA regarding geographical references and dates for further discussion of the proposal, which may interest you. —sroc 💬 08:43, 7 November 2013 (UTC)

Abc conjecture

The problem at the moment is that a week ago, User:Isheden redirected Constant (mathematics) to the disambiguation page, Constant, which has a dozen meanings ranging from math and physics to popular culture topics, with no clear means of determining which kind of constant is intended for any given link. Should that redirection be reversed? bd2412 T 17:25, 7 November 2013 (UTC)

Yes, I think so. —David Eppstein (talk) 18:15, 7 November 2013 (UTC)

Thanks. Being out of my depths, I have reverted my various attempted fixes of these links. Cheers! bd2412 T 18:25, 7 November 2013 (UTC)

DYK for Elena Mrozovskaya

The DYK project (nominate) 09:32, 9 November 2013 (UTC)

Request for help

David Eppstein,

Hello! I'm a fairly new Wikipedia editor, and I've spent a lot of time working on Finite subdivision rule. I was wondering if you would mind looking it over briefly; it's an article on an area of math vaguely related to cellular automota and strongly related to hyperbolic geometry and circle packings. I've never created an article from scratch like this, so if you have the time, I'd really appreciate some feedback. Sorry if this is the wrong way to request help like this. Thanks!Brirush (talk) 02:49, 12 November 2013 (UTC)

Natalie Holland

I notice that you deprodded Natalie Holland. I didn't add the prod myself, but I do happen to agree with it, is it too late to endorse it or should I AfD it?--Launchballer 13:52, 13 November 2013 (UTC)

Once an article has been deprodded, it can't be re-prodded, so you should AfD it. —David Eppstein (talk) 16:44, 13 November 2013 (UTC)

Degeneracy and realization of the monogon and digon

Hi David, you might like to contribute to the discussion at Talk:Polygon#Degeneracy_and_realization about some edits you made recently. — Cheers, Steelpillow (Talk) 09:04, 14 November 2013 (UTC)

Korean physicists

Not that those articles are acceptable as they are written, but to pass BLPROD they just need the official CV or other sufficiently reliable source for verification, not a third party source.

The question is, how much rewriting should we be doing? I really don't have the time to do everything necessary, tho many would I think pass WP:PROF. See my edits on Chang Hee Nam (he's a fellow of the APS, and that has usually counted for notability ) and my comments at User talk:Kofst1254 DGG ( talk ) 04:35, 17 November 2013 (UTC)

Sure, but they didn't even have that much. And I agree that most of them look notable, but I suspect many of the better sources are in Korean, making it problematic for those of us who don't read the language to try fixing up the articles. —David Eppstein (talk) 05:21, 17 November 2013 (UTC)

Possible socks?

Hi David, re this and this, I'm not sure, but perhaps it's worth checking whether user POLY1956 (talk · contribs) and user BOOLE1847 (talk · contribs) might be one and the same person? FWIW, I have asked both users on their talk pages. Cheers - DVdm (talk) 22:57, 23 November 2013 (UTC)

Ugly?

I guess it was as that sort of bigoty is always ugly, but that felt like a comment about me. Dougweller (talk) 06:12, 25 November 2013 (UTC)

I hope you don't mean that I thought your outrage at the bigotry on show was inappropriate — that wasn't my intent. But the conversation took an argumentative turn that I didn't feel was constructive at all. —David Eppstein (talk) 06:57, 25 November 2013 (UTC)

Thanks, I'm relieved. Yes, it was getting into a rather stupid argument - I'm not sure I understand even now what the other editor was getting at. I see the IP is blocked. It geolocates appropriately so it probably is him. Dougweller (talk) 11:49, 25 November 2013 (UTC)

November 2013

Hello, I'm BracketBot. I have automatically detected that your edit to Barry Mazur may have broken the syntax by modifying 2 "{}"s. If you have, don't worry: just edit the page again to fix it. If I misunderstood what happened, or if you have any questions, you can leave a message on my operator's talk page.

List of unpaired brackets remaining on the page:

• {{quote|produces, without effort, innumerable problems which have a sweet, innocent air about them,

Thanks, BracketBot (talk) 07:44, 25 November 2013 (UTC)

Geometric Progression and Geometric series sum formula derivation

Hello, I am Raghavendra Lingayya. I given external link so that the readers can get detailed truth about the changes i made. If you remove it, there is no problem for me, but it is a problem for those who want to study Geometric Progression.

I teach numbers 1 2 3 4 and 1 3 5 7 using R-analysis and tell the students to derive the formula to find sum of GP, they automatically derive this formula using R-analysis (Raghavendra's Analysis). Means, there is no need to teach derivations for series if one just studied a number using R-analysis.

I did about ten years of research only on few numbers pattern.

My sir told that the truth there is no derivation for the series to find sum of first n natural numbers, squares, cubes, etc. This truth result in finding derivation for the series. But to understand the difference between automatic mathematics and answer getting mathematics, one has to to see the both.

Sir, you removed the truth about the method. Teachers will teach that trick as mathematics. This is nothing but cheating the students. What they understand in this derivation? How this method helps to solve other series? Is the contain any study on the given question? But if do not removed that truth, then there will help in starting discussion on the present method and real method, so that in feature it helps to get true mathematics for millions of students in their curriculum.

Do you find any wrong in telling the method as Trick? Why? Do you think the method given is the right algebraic derivation? Why? I am expecting your answers. I hope real mathematical derivation is not starting knowing the answer before or not starting using the external tricks.    
  I am very happy about you on starting discussion on it. You can re-write my article or add my article again in wiki if you will find that it helps the feature generations to get real mathematics.  — Preceding unsigned comment added by Rahaven (talk • contribs) 11:14, 28 November 2013 (UTC) 

Sipser-Lautemann

Hi David, Domotor Palvolgyi here. I am no expert in wiki, I am writing to you to report a mistake on the http://en.wikipedia.org/wiki/Sipser%E2%80%93Lautemann_theorem page which I saw you edited. The page gives two proofs for the theorem and claims the first is based on Sipser(-Gacs) and the second on Lautemann but in fact both proofs are the same (based on Lautemann), Sipser used hash functions. Hope you know how to deal with the problem...

Ps. I really don't think it's correct to call it Sipser-Lautemann theorem as the first person to prove the result was Gacs, see e.g. Trevision calls it Gács-Sipser-Lautemann: http://lucatrevisan.wordpress.com/2010/04/27/cs254-lecture-5-the-polynomial-hierarchy/ — Preceding unsigned comment added by 80.98.160.141 (talk) 12:19, 28 November 2013 (UTC)

Tsukiyama algorithm

I've been going through the material you added on Tsukiyama's algorithm for enumerating maximal cliques. I was a bit confused about the first part but have since realized my mistake, see Talk:Clique problem#Tsukiyama algorithm stated incorrectly, but I'm still not convinced that the algorithm as described is completely correct. The problem is the passage:

"Using these observations they can generate all maximal cliques in G by a recursive algorithm that, for each maximal clique C in G \ v, outputs C and the clique formed by adding v to C and removing the non-neighbors of v. However, some cliques of G may be generated in this way from more than one parent clique of G \ v, so they eliminate duplicates by outputting a clique in G only when its parent in G \ v is lexicographically maximum among all possible parent cliques."

There doesn't seem to be any way to avoid the issue that C∩N(v)∪{v} is not necessarily maximal without specifically testing for it. The test is easy, namely that C∩N(v) must be a maximal clique in N(v). But the lexicographic maximum condition on C does not guarantee this will be true. For a counterexample, take G={1, 2, 3} with a single edge {23}, C={1} and v=3. C is the lex. maximum clique in G \ v but C∩N(v) is empty. With the additional test I was able to turn your description into Python code that produced a result matching the Bron–Kerbosch algorithm and my own crude methods.

The secondary sources I found on-line for the algorithm describe it very differently than the WP article, more of a tree traversal where the nodes of the tree are the maximal cliques and the condition defining an edge between nodes is rather complex. Given how much the algorithm has evolved and that (so I gather) it is the starting point of other output sensitive algorithms including that of Makino & Uno and of Johnson & Yannakakis, it seems like there is more than enough material for a separate article on the algorithm. --RDBury (talk) 07:53, 3 December 2013 (UTC)

The Wikipedia Library Survey

As a subscriber to one of The Wikipedia Library's programs, we'd like to hear your thoughts about future donations and project activities in this brief survey. Thanks and cheers, Ocaasi ^{t | c} 15:40, 9 December 2013 (UTC)

Discussion at Wikipedia talk:Naming conventions (geographic names)#En dash vs. "and" for multi-state metro areas

You are invited to join the discussion at Wikipedia talk:Naming conventions (geographic names)#En dash vs. "and" for multi-state metro areas. Herostratus (talk) 18:32, 11 December 2013 (UTC)

Best rational approximation

What book is your reference for the usage of "best rational approximation" in the area of a disk page? The notion of "best rational approximation with denominator less than X" is clear and I understand the connection with continued fractions, but the usage here seems to me prone to misinterpretation. Ebony Jackson (talk) 19:42, 13 December 2013 (UTC)

Searching Google books for 355/113 "best rational approximations" finds many. Here's one. See also Continued fraction#Best rational approximations. —David Eppstein (talk) 20:08, 13 December 2013 (UTC)

Thank you for the reference to Stein's book. I couldn't find the definition of the technical term "best rational approximation" there, however. He speaks of "the best rational approximations" in an informal way, and then speaks of the "best rational approximations of π with given denominator size" to clarify. I checked the first few Google Books results for 355/113 "best rational approximations", but they too do not give the precise definition and instead qualify the term as in "the best rational approximations with restrictions on the sizes of the denominators". I believe you that there must exist a definition somewhere, but I am not sure that it is so commonly used. The Wikipedia page you cited does give the definition you are using, but it does not cite the reference it got it from, so it would still be nice to have a notable math book with this definition, if you happen to know one. Ebony Jackson (talk) 03:41, 14 December 2013 (UTC)

OK, given your response, I kept the term "best rational approximation", but just added a little clarification. Thank you, Ebony Jackson (talk) 18:42, 17 December 2013 (UTC)

Looks good. —David Eppstein (talk) 18:44, 17 December 2013 (UTC)

Space of stable maps

Just wanted to say I agree with the redirect; somehow it didn't occur to me there might be an article called stable map. (In fact, I think it's a wrong title.) -- Taku (talk) 13:01, 17 December 2013 (UTC)

AC

Hi, I saw your revert.

The antichain principle, every partially ordered set has a maximal antichain, is an equivalent of the axiom of choice and listed (and linked to Antichain) in that article. That's why I categorized it. YohanN7 (talk) 03:04, 20 December 2013 (UTC)

Ok, but the antichain principle is nowhere mentioned in the antichain article. Categorization should be based on article content, not on mentions in other articles. —David Eppstein (talk) 04:49, 20 December 2013 (UTC)

You are right. I was to fast and more or less assumed that the antichain principle was mentioned. (Perhaps the article should mention it?) YohanN7 (talk) 05:25, 20 December 2013 (UTC)

Sounds like a reasonable thing to mention to me. —David Eppstein (talk) 05:31, 20 December 2013 (UTC)

Midpoint stretching polygon.svg

Hey, nice work on the diagram, and thanks for contributing it! Melchoir (talk) 02:10, 22 December 2013 (UTC)

You're welcome! —David Eppstein (talk) 03:08, 22 December 2013 (UTC)