User talk:David Eppstein/2015a

Happy new year to You
Happy new year to You, I am Dao Thanh Oai --118.70.131.119 (talk) 03:48, 1 January 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. NorthAmerica1000 13:41, 1 January 2015 (UTC)

Send New Year cheer by adding {{subst:Happy New Year 2015}} to user talk pages.

DYK for Congruum
 Harrias  talk 12:01, 2 January 2015 (UTC)

DYK for Ioana Dumitriu
Harrias talk 00:41, 4 January 2015 (UTC)

Dao's theorem on six circumcenters
Dear Dr. David Eppstein, When You have a time, could you review the Dao's theorem on six circumcenter:


 * For each side of a cyclic hexagon, extend the adjacent sides to their intersection, forming a triangle exterior to the given side. Then the segments connecting the circumcenters of opposite triangles are concurrent.

Thank to You very much, I am Dao Thanh Oai — Preceding unsigned comment added by 117.6.86.37 (talk) 13:26, 5 January 2015 (UTC)

DYK for Linda Preiss Rothschild
Cas Liber (talk · contribs) 12:02, 11 January 2015 (UTC)

on the upper bound of TSP path
The current wiki TSP page shows "the currently best upper bound is beta<=0.92** ". It is an upper bound too high. Computer experiment will result in a short path with beta<=0.8 without too much difficulty. My experimental result is 0.718, and an old paper shows 0.7120+0.0002, which serve as a better upper bound. See "The Random Link Approximation for the Euclidean Traveling Salesman Problem" at

http://sites.cgu.edu/percusa/files/2013/08/tspjdp.pdf

So please update the upper bound on the wiki to a lower value. If computer experiment did not convince you, analyzing the distribution of nearest points algebraically will be an interesting discussion. One clue is: TSP shorest path usually takes the 1st nearest or 2nd nearest points as next point. If the path always takes the 2nd nearest then the resulted legnth is always higher. 2nd nearest results in 0.75 which also serve as an upper bound. — Preceding unsigned comment added by Lingwanjae (talk • contribs) 17:06, 11 January 2015 (UTC)
 * First, here is a difference between what we can prove rigorously and mathematically, and what experiments tell us the truth is likely to be, and we should be very clear about that difference in the article. And second, unless you publish your experimental results in a peer-reviewed conference or journal, we can't use them here; see WP:NOR. —David Eppstein (talk) 17:35, 11 January 2015 (UTC)

I read that WP:NOR and agree the style of wiki. Statementes should be at least peer-reviewed. The paper in the above is peer-reviewed. It should be harmonic to the wiki policy, althought it is an article 19 years ago. I have been chasing the exact length of TSP long before that year, wish someone can prove or disprove the exact length is sqrt(N/2) in this year by the stimulation of peers.

DYK for Gigliola Staffilani
The DYK project (nominate) 16:28, 13 January 2015 (UTC)

Stylization of the "common name"
In January 2013 there was a "RfC on COMMONSTYLE proposal" at WT:AT in which you expressed an interest. FYI there is a similar debate taking place at the moment, see Wikipedia talk:Article titles -- PBS-AWB (talk) 12:20, 16 January 2015 (UTC)

Bonnie Berger article
Thanks for getting this started! I was in the process of putting together a draft article so I'll add what I have. Amkilpatrick (talk) 20:25, 17 January 2015 (UTC)
 * You're welcome! She clearly warrants having an article here; it's a bit surprising to me that she didn't have one already. —David Eppstein (talk) 20:42, 17 January 2015 (UTC)

Jenő Lehel
dear professor Eppstein, thanks for your immediate help. i just noticed a few days ago that i am not on the list of mathematicians with Erdos number 1, and decided to add myself to wikipedia. i used Zoltan Furedi's autobiography as a template, i believe, the form of the references and the content of my autobiography lines are correct, as far as math is concerned. thanks for any further advice which helps complete my submission. — Preceding unsigned comment added by Yency (talk • contribs) 05:40, 19 January 2015 (UTC)
 * My advice is: don't do it. Your expertise is very welcome here but it would be better to find subjects for which you have less of a conflict of interest. —David Eppstein (talk) 06:15, 19 January 2015 (UTC)

Comment- I have removed the tag placed on the draft article. We don't normally tag draft articles since they are not searchable and not in the active article space. Yency is currently going about this the best way we recommend using the WP:AFC process which allows for experienced editors to review articles before they get moved into the primary article space. Yency should also read through some of Wikipedia's policies which I have linked on his talk page.- McMatter (talk)/(contrib) 14:18, 19 January 2015 (UTC)

Christiaan Heij
Thanks for your feedback on the article creation. I commented on it on its talk page. If you think there is more to it, please let it know. -- Mdd (talk) 08:27, 20 January 2015 (UTC)

Doctoral advisor
I don't want to get into an edit war with you over Doctoral advisor, but I need to explain that your justification for changing from to  was incorrect. You wrote, "please don't change from Citation Style 2 to Citation Style 1 without discussion." Both templates use Citation Style 1. See: Template:Citation/core:
 * These templates have been converted to use Module:Citation/CS1 so no longer use
 * Template:Citation
 * Template:Cite book

Under ideal circumstances, has basically the same output as the  templates, or at least the most common ones. But circumstances are not always ideal. Sometimes, when the title is an article title and not a book title, guesses wrong, assumes the title is a book title and puts it in italics. For this reason, I never use and routinely change it to the appropriate  template. As a side benefit, the next editor who wants to improve on the citation knows immediately that it is a book, news item, press release, or whatever, and knows to to search for more info about the item based on what type of item it is.

There is one difference, which is that 's separator defaults to comma and  's separator defaults to period; both templates allows the separator parameter to be changed.

In summary, I didn't change citation styles; I merely substituted a more reliable template for the template, which in the best case, gives the same result as  (except for default separator) and in the worst case outputs incorrect information. Anomalocaris (talk) 19:41, 20 January 2015 (UTC)
 * You are wrong, were told you are wrong, and still arguing rather than conceding that you were wrong. See WP:CITEVAR: "Editors should not attempt to change an article's established citation style..without first seeking consensus for the change." See also Help:Citation Style 2 for a description of the style used by citation, which is indeed different from the style described in Help:Citation Style 2 (for instance, it separates parts of the citation by commas rather than periods). The fact that both citation styles are implemented using the same underlying core code is irrelevant. Countering your supposed "side benefits" of your switch to the citation style: cite conference is broken and there is no good CS1 way of referring to conference proceedings (it can be made to work but there has been serious discussion about discontinuing this option); CS1 does not by default work with the harv series of referencing templates, and CS2 does; editors do not have to remember a half-dozen different templates with subtly-incompatible-from-each-other parameter names, they can just use the one citation template; template formatting software (such as what I use to generate these things) also does not have to guess which of the many templates is the right one to use; we avoid the (frequently occurring) error in which an editor chooses the wrong template; etc. —David Eppstein (talk) 21:22, 20 January 2015 (UTC)

Enneahedron
Hello David. I am an avid fan of geometry and math who recently updated the enneahedron page. Regarding this page, why did you remove the photo of diminished trapezohedron and its description from the examples section? I don't see why it is "spammy" as you said in the notes section after its removal. Here they are for ease of reference https://en.wikipedia.org/w/index.php?title=Enneahedron&oldid=644048369

The image is here https://en.wikipedia.org/wiki/Diminished_trapezohedron#mediaviewer/File:Diminished_square_trapezohedron.png My updates were a good faith effort to add interesting content. This includes the additional images of the enneahedron found here http://traipse.com/nine/ where the centers of each face are equidistant to the spatial center. The shape appears symmetrical (as well as aesthetically pleasing). I apologize for my clunky editing process, I am fairly new to edit-making. However, I took time and thought to offer these additions, please explain whether or why you considered such additions objectionable. I am a genuine enthusiast of math and space geometry, as well as a sequence contributor to OIES--as such. I have no intention of adding anything "spammy." — Preceding unsigned comment added by PMChema (talk • contribs)
 * Removing the figure wasn't the main intent of my undo — it was more aimed at two other aspects of your recent edits:
 * The references linked to traipse.com appear to be self-published sources in violation of our requirements that article content has reliably-published sources, and
 * You changed the description of the associahedron from text that stated that the polyhedron itself is three-dimensional to text that instead stated that it is embedded into three-dimensional space. This is a mistake. It doesn't matter what dimension the space is, what matters is that the polyhedron itself is the three-dimensional one. For instance, for the closely related family of permutohedra, the usual description of the three-dimensional permutohedron embeds it into four-dimensional space, but it is still a three-dimensional polyhedron, just like a square in three-dimensional space (such as a flat sheet of origami paper) is still itself a two-dimensional thing.
 * —David Eppstein (talk) 03:36, 25 January 2015 (UTC)

Duly noted. I had changed the description in an attempt to add a link to "3D" for easy reference. Didn't mean to confuse. At any rate, I will add back the image of the Diminished_square_trapezohedron another time. Have a good evening. — Preceding unsigned comment added by PMChema (talk • contribs) 03:46, 25 January 2015 (UTC)
 * The image can probably be included in the table of images with the others in the Examples section, if it can be done without making a mess of the table. BTW, for future reference, it would be helpful if you could sign your talk page comments by typing four tilde characters (" ~ ") at the end of them. —David Eppstein (talk) 03:49, 25 January 2015 (UTC)

Representation theory of SL2
Thank you for your recent edit over there. The article still lacks inline references, but that is a separate problem. It should be made mandatory to use templates for references as well as for inline citations to the greatest extent possible. It makes reuse of references (meaning creating new inline citations) so much simpler. There are plenty of articles having the complete reference given inline whenever a citation is given. It strongly discourages adding new references and citations, and makes the source text harder to navigate. If I can find some support for the idea, I'll make a proposal in the appropriate place. YohanN7 (talk) 08:16, 27 January 2015 (UTC)
 * I agree with you (pretty much) but you can save your breath. WP:CITEVAR. Some people are quite fierce about this, for unknown reasons. EEng (talk) 13:20, 27 January 2015 (UTC)
 * Thanks, Yohan. Re CITEVAR: true, and probably it would doom any proposal to require the use of citation templates, but I have a different reason why I think requiring them might be a bad idea: they have grown both more complicated over the years, and more rigid in the combinations of parameters that are required or disallowed, so that I don't think they're easy for new editors to learn. I'd rather get people in the habit of providing citations at all, in whatever format is easiest, before pushing secondary considerations like formatting them consistently. As for my excuse in sort-of-violating CITEVAR by wholesale replacement of manually formatted citations with templates: usually the manually formatted ones are not already in a consistent format, so there's no pre-existing format to retain. —David Eppstein (talk) 17:20, 27 January 2015 (UTC)
 * Your point about new editors is a good one. I wouldn't mind a guideline that favors templates as the eventual mode for any given article, but any kind of "requirement" adds even more to the already steep WP learning curve. EEng (talk) 17:43, 27 January 2015 (UTC)
 * (EC: This was written before David's reply appeared) The WP:CITEVAR does not really apply to what I am talking about. It is not about enforcing some particular style. It is about enforcing some style, any which one. The exception is that it would enforce a list of references at the end separate from the list of citations (that is generated any which way). Nobody in their right mind could oppose strongly to this. Articles that emerge from the beginning as no-style are just the result of laziness on part of the editor putting the first reference in, with the result that the article becomes unworkable from the citation point of view in the long run.


 * EEng, could you ask your grandmother to throw a tea party for her bridge club friends and plant the idea? I'd like to hear what they have to say.


 * David, I understand your point about complicated templates. Difficulties are supposed to overcome. YohanN7 (talk) 17:29, 27 January 2015 (UTC)


 * Not really sure what you're saying here, Y. EEng (talk) 17:43, 27 January 2015 (UTC)


 * Talk:Closed subgroup theorem YohanN7 (talk) 18:21, 27 January 2015 (UTC)
 * I mean about the bridge club. EEng (talk) 18:42, 27 January 2015 (UTC)
 * Some of the ladies in my grandmother's bridge club... These are the ones of your grandmothers friends whose opinion I want. Not just any random friends. Some of them (a couple of poker sharks) are not to be trusted – or so I have heard at least. YohanN7 (talk) 19:02, 27 January 2015 (UTC)
 *  EEng (talk) 19:14, 27 January 2015 (UTC)


 * Are you telling me that this post at talk:closed subgroup theorem is not by you? It is signed by you.
 * I really agree about the style. Some of the ladies in my grandmother's bridge club were discussing just this point. "EEng", said Mrs. Abramowitz, "we got as far as embedded submanifolds always having the subspace topology, but after that we were really stumped. This should really be written more for people who don't already understand this kind of material well. Sheila, weren't you just saying that it would help if von Neumann's proof for the special case of groups of linear transformations was explained first? Five no-trump." EEng (talk) 11:06, 18 July 2014 (UTC)
 * I thought you had a sense of humor. Backing off as well. Sorry David for trashing your page. YohanN7 (talk) 19:28, 27 January 2015 (UTC)
 * Sorry, but I'd thoroughly forgotten that -- I toss off so many droll and clever things each day I can't be expected to remember tham all. Somehow I missed the link you posted back to the article's talk. So if there's still something DE can do for you, maybe you better just start over and I'll be quiet. EEng (talk) 20:29, 27 January 2015 (UTC)


 * Dear Dr. David,

I a generalization Napoleontheorem at http://www.artofproblemsolving.com/Forum/blog.php?u=192421&b=112442

Please see that: — Preceding unsigned comment added by 117.6.86.37 (talk) 18:15, 28 January 2015 (UTC)

The fundamental theorem of arithmetic
The fundamental theorem of arithmetic is about the prime decomposition of a number, a concept that can be considered advanced, that is, above general mathematics, as far the general education on mathematics goes. This is why a complete, clear definition is necessary. In its current form in the "Integer factorization" article, the definition is based on an "appropriate notion of the empty product". The notion of the empty product is an advanced concept in terms of general mathematics, and one is not supposed to be familiar with it. It is also not necessary for stating or proving the theorem. This is why I decided to give the definition in which one is a special case. Which is mathematically neccessary, if one does not introduce a definition for the empty product. I believe this makes the definition more accesible to the general audience. In its current form it is hard to understand, for the average reader. Nxavar (talk) 20:31, 1 February 2015 (UTC)

GamerGate Discretionary sanctions notice
Dreadstar ☥   21:06, 1 February 2015 (UTC)

claw-free independent set
The algorithm described in Claw-free_graph is wrong. Specifically, the following claim is false: "A simple path in this switch graph between two unsaturated vertices corresponds to an augmenting path in the original graph". I drew a simple counterexample here. Can I delete the claim? Tokenzero (talk) 21:17, 6 February 2015 (UTC)
 * Ok, I agree that it looks like a counterexample. Rather than just deleting it, could you possibly replace it by a more correct description of that part of Sbihi's algorithm, though? —David Eppstein (talk) 21:35, 6 February 2015 (UTC)
 * Uufff, I went through the paper again, but it's really just the same idea as in Edmonds' blossom algorithm with a huge amount of technical details. I tried to rewrite the section to describe both approaches slightly better, and included a mention of the best known (cubic time) algorithm. Thanks for checking it out. Tokenzero (talk) 23:45, 8 February 2015 (UTC)
 * And thanks again both for catching this problem and for your rewrite of this section. —David Eppstein (talk) 23:50, 8 February 2015 (UTC)

Please check: http://tube.geogebra.org/student/m640503 — Preceding unsigned comment added by 113.20.108.135 (talk) 05:53, 7 February 2015 (UTC)
 * What should I check about it, and why? —David Eppstein (talk) 06:03, 7 February 2015 (UTC)

Sergey Zonenko
Good afternoon. Can you restore the page Sergey Zonenko. We have removed the entire sentence that you want to have links. All information has been confirmed. More than a week you had no claim to the page. Explain what the problem is.Ogeldke (talk) 09:53, 13 February 2015 (UTC)


 * If it were deleted after a simple WP:PROD, then yes, I could restore it. But it was deleted after the consensus of a full deletion discussion, Articles for deletion/Sergey Zonenko. Unless you have new and convincing evidence of notability that was not already considered in the discussion, it's not going to be restored. There's a process, WP:DRV, for appealing deletion decisions like this one, but only on the grounds that they were improperly decided, which appears very unlikely to succeed in this case. —David Eppstein (talk) 17:19, 13 February 2015 (UTC)

Can You help with the MRB constant?
DR. David Eppstein, Thank you for your interest in the MRB constant, even if its only for the sake of the Table of Constants. I can agree with you about membership to such a short table of constants having a higher standard that of just an article. I noticed you had some opinion on the MRB constant being notable enough to have an article. I know your so busy that you might say no to my request, but is there anything you can do to help save the MRB constant article? It has been facing some tough criticism on its talk page that I don't think it fully deserves. Have you noticed the late Richard Crandall's paper that briefly discusses the constant at http://web.archive.org/web/20130430193005/http://www.perfscipress.com/papers/UniversalTOC25.pdf ? It has a section for the computation of the MRB constant on pages 28 and 29. I think it would be helpful if anyone could prove his eta formulas in a paper of some sort! There is also a program he wrote that is in that I think uses one of the eta formulas (it is hard to tell!) to accelerate convergence by a factor of 10 over Cohen's Method alone. Thank you whether or not you can do anything else for it. I hope I at least intrigued you a little. Marvin Ray Burns (talk) 01:29, 16 February 2015 (UTC) If nothing else, would you post your thoughts on why the MRB constant is notable enough to have its own article in the talk page, I think your comments would have some weight on whether the article gets to remain in Wikipedia.Marvin Ray Burns (talk) 20:51, 16 February 2015 (UTC) Not to leave you in the dark, but I fully explained Crandalls super-fast program for computing the constant in the post that starts with "Crandall is not using his eta formulas directly!!!!!!!" at the following URL. http://community.wolfram.com/groups/-/m/t/446025?p_p_auth=HV4olXHN Marvin Ray Burns (talk) 22:08, 20 February 2015 (UTC)

Amanda Palmer censor
FYI, I have added a note to WP:ANI regarding this IP user. I hope that's the appropriate action to take. Thanks for your recent revert. DaveSeidel (talk) 21:55, 17 February 2015 (UTC)

Herr Doktor, I thought you might find this interesting
...(if startling) EEng (talk) 15:39, 18 February 2015 (UTC)
 * Herr Professor Doktor, I think you mean. Weird. my colleagues do know that I spend a lot of time editing Wikipedia but I think they would laugh at the idea of giving me any credit for it in promotions. —David Eppstein (talk) 16:34, 18 February 2015 (UTC)

Article about Vladimir Arnold
Hi, professor David Eppstein.

I would like your opinion about some possible issues on the article about Vladimir Arnold.

I wanted to find a reference for this passage: "While a student of Andrey Kolmogorov at Moscow State University and still a teenager, Arnold showed in 1957 that any continuous function of several variables can be constructed with a finite number of two-variable functions, thereby partially solving Hilbert's thirteenth problem.", and so I searched for one on Google Books, but I couldn't find any, and that's because all sources I have found there don't mention "partially" – they say he solved it, completely, without this "partially". For example: https://books.google.com/books?id=SpTv44Ia-J0C&pg=PA5, https://books.google.com/books?id=GHFtMc9NTkYC&pg=PA130 and https://books.google.com/books?id=dx9yxsRUgtAC&pg=PA55 https://books.google.com/books?id=iQPjBQAAQBAJ&pg=PA262.

So, what can I do? Should I modify the page or should I leave it there without references or mark for "citation needed"?

Unfortunately, If he solved it completely or only partially I'm not able to judge by myself.

Sorry for my bad English.

P.S. Another thing, https://tools.wmflabs.org/xtools-articleinfo/index.php?article=Vladimir_Arnold&lang=en&wiki=wikipedia#maintenance says that the passage "at the beginning of the school year, when he usually was formulating new problems" may contain a grammatical error. To me it looks right, but I'm not sure about it.

Sincerely, Анна Лаура Коновалова (talk) 08:03, 19 February 2015 (UTC)
 * According to our article Hilbert's thirteenth problem, Arnold solved the problem completely for the class of continuous functions, but the original formulation was for algebraic functions. So maybe that's what the "partially" means? But please, go ahead and modify the page as you see fit. As for the supposed grammatical error, "usually was" would be a little better "was usually" but I think it's ok either way. —David Eppstein (talk) 08:09, 19 February 2015 (UTC)
 * Thank you. I decided that I won't do anything on the article. I will only paste this same message I sent to you on the discussion of the article in order to attract attention to the matter, because I don't feel confident enough to change the article's content. Анна Лаура Коновалова (talk) 08:16, 19 February 2015 (UTC)

Talkback
 Arun Kumar SINGH (Talk)  07:36, 20 February 2015 (UTC)

Walter Lewin
Dear David Eppstein,

I am a bit new to editing Wikipedia pages so please pardon my ignorance. You seem to be reverting my changes on Walter Lewins page concerning the edX versions of his lectures. Is there a specific reason for this?

Thanks, Daniel Dekkers (d.dekkers@cthrough.nl) — Preceding unsigned comment added by Daniel Dekkers (talk • contribs) 17:06, 20 February 2015 (UTC)
 * A few reasons: (1) there is no longer an official site at MIT that we can link to, and no canonical choice of alternatives; (2) if people want to find them, they can use Google; (3) the reason MIT took the online courses down, rather than merely firing Lewin, was that he was seeking out people taking the courses as potential new victims for his sexual harassment, and MIT didn't want to participate in helping him find more victims. Do you think Wikipedia should take on that role? —David Eppstein (talk) 17:12, 20 February 2015 (UTC)
 * What an ignoble end. EEng (talk) 19:54, 20 February 2015 (UTC)
 * Yes, it's a sad story. Unfortunately he's far too notable not to talk about it in an article. —David Eppstein (talk) 20:01, 20 February 2015 (UTC)

Maximal independent set
Hi,

You undid my edit to that page, asking "what is the point of using the coloring? You can find an MIS in linear time, easily.". As explained in the reference I put there, the point is that there are parallel algorithms for vertex coloring that work in logarithmic time. --Erel Segal (talk) 06:01, 22 February 2015 (UTC)

Knuth's error in tracing lg
This is interesting. I have checked Knuth's website and I could not find the errata about Reingold's \lg suggestion in Vol.1, ACP. Maybe it is just a suggestion, not the very beginning?

If this tracing is a widely recognized error, why Knuth did not list it in the errata?

Thanks.

--IkamusumeFan (talk) 20:31, 22 February 2015 (UTC)
 * I'm not sure Knuth had been told of the error; I just sent a note about this to the AOCP address. It's something I learned recently myself while improving the binary logarithm article. —David Eppstein (talk) 20:45, 22 February 2015 (UTC)

Promotional "reward board" entry
I wonder if you think this is appropriate, particularly the exhortation, "Try to incorporate a section on the MRB constant in it", given the identity of the editor offering the reward. EEng (talk) 23:12, 27 February 2015 (UTC)
 * No, I think it's too big of a conflict of interest. Worth bringing to WP:COI/N maybe? —David Eppstein (talk) 00:01, 28 February 2015 (UTC)
 * I guess he watches this page as a result of his post here just above. EEng (talk) 16:26, 2 March 2015 (UTC)

px1
I was leaning toward removing it as well, however, your reasoning for removing it is better than mine. since I don't have Chrome on OSX, can you tell me if you see a difference between [//en.wikipedia.org/w/index.php?title=Template:Px1&oldid=649611699 this version] and [//en.wikipedia.org/w/index.php?title=Template:Px1&oldid=608021869 this version]? basically, I would like to know if the issue you were observing goes away when I used the [//en.wikipedia.org/w/index.php?title=Template%3APx1&diff=649611699&oldid=608021869 additional visibility statement]. my feeling is this can be replaced by hsp, which probably doesn't have the same issues, but it may be useful to make sure they both work. Frietjes (talk) 00:08, 3 March 2015 (UTC)
 * The new visibility=hidden version does not show the visible box, so I guess it's an improvement? I hope hiding the zwj doesn't also suppress its no-break functionality. —David Eppstein (talk) 00:12, 3 March 2015 (UTC)
 * Since I created this template (and seem to be its only aficiando) can you tell me what's going on? EEng (talk) 03:30, 3 March 2015 (UTC)
 * In case you didn't see it, the problem was that px1 was showing a visible box character (the one you get for a character you don't have in your fonts). As for why, an html rendering bug in Chrome/OS-X would be my guess. I tried making sure my copy of Chrome was up to date but that didn't help. Searching Google for zwj chrome bug finds some hits but I'm not sure of an exact match. —David Eppstein (talk) 04:35, 3 March 2015 (UTC)
 * Weird. I've been using it heavily in a half-dozen articles for just about a year now, and this is the first I've heard. EEng (talk) 04:49, 3 March 2015 (UTC)

H-index
If you have the appropriate machinery at your disposal, can you work out the h-index mentioned here ? EEng (talk) 21:52, 3 March 2015 (UTC)

Could you help me review and edit if you think should keep
Dear Dr. David,

Could you help me review and edit if you think should keep:

https://en.wikipedia.org/wiki/Dao%27s_theorem_on_six_circumcenters

--Hophap124 (talk) 14:20, 4 March 2015 (UTC)

Contested deletion of Dao's theorem on six circumcenters
This page should not be speedily deleted because... (your reason here) --117.6.86.31 (talk) 02:20, 5 March 2015 (UTC)


 * * First reason, the old article and this article are different: The old article write sum theorems of Dao Thanh Oai with common title is: Dao's theorem, The old article have some subsections: Dao's theorem on concurrent of three Euler lines, Dao six point circle, Dao six circumcenters theorem and Dao eight circles problem. So the old article and this article are different. And the old article Dao Thanh Oai is not enough english language to chat with You. He did not understand what you said that. And he didn't known wiki.


 * * Second reason, enough reliable sources: The old article write some subsections, but one subsection had only reliable source. But now this article has engough reliable sources: It has two papers in Forum Goemetricorum, one entry in Kimberling center, and two reviews in Zentralblatt MATH, one topic in Cut the Knot and some communiation of geometers in: Advanced Plane Geometry


 * * Third reseon, not too soon: The theorem appear since 2013,


 * * Fourth reseon, nice: The theorem nice as:

--117.6.86.37 (talk) 13:19, 5 March 2015 (UTC)
 * Seven circles theorem
 * Six circles theorem
 * Five circles theorem

About Dao Thanh Oai
Dao Thanh Oai is an amateur geometer, but I think he is not trivial why? You can see somes his results:


 * His generalization of the Napoleon theorem: http://tube.geogebra.org/student/m660461


 * His generalization of the Gossard perspector theorem: http://tube.geogebra.org/student/m645553


 * His generalization of the Simson line theorem: http://tube.geogebra.org/student/m527653

He has many another results. Publish in 2014 in somes Journals — Preceding unsigned comment added by 117.6.129.14 (talk • contribs)

Could you tell me that why some one want to delete the Dao's theorem on six circumcenters?? --Hophap124 (talk) 06:02, 6 March 2015 (UTC)
 * You could try asking them instead of me, but it might have something to do with your relentless self-promotion and flouting of anti-COI guidelines. —David Eppstein (talk) 06:21, 6 March 2015 (UTC)

But I see the theorem like as: *


 * Seven circles theorem
 * Six circles theorem
 * Five circles theorem

Calculation by Mathematica sofware:

Please see: https://groups.yahoo.com/neo/groups/AdvancedPlaneGeometry/conversations/messages/1539 --Hophap124 (talk) 07:11, 6 March 2015 (UTC)ư

Thank to You, but I have not engough english to chat with them. If You think the result is nice, please comment--Hophap124 (talk) 07:19, 6 March 2015 (UTC)

Request for comment
There's a request for comment opened on the "Involuntary Celibacy" article, with the same editor trying to restore it as the one who tried to do so previously with the latest Deletion Review. I thought you might be interested in this because of your previous involvement in the subject. Mythic Writerlord (talk) 20:33, 15 March 2015 (UTC)

.
This was only in December 2014,  are we recreating it already? Hafspajen (talk) 21:28, 15 March 2015 (UTC)

Georg Nees
Hello David Eppstein,

Thank you for your work on the article about George Ness. I am from Germany and working now to update the article about Georg Nees in the Wikipedia Germany. Your work is a great help to make the article better. - --Maxim Pouska (talk) 23:46, 21 March 2015 (UTC)

Some stroopwafels for you!

 * Thanks! I hope to get a chance to have some real stroopwafels when I visit NL again later this year. (Trader Joe's sells some packaged ones locally but they're not as good.) —David Eppstein (talk) 15:47, 24 March 2015 (UTC)