Wikipedia talk:WikiProject Mathematics/Archive/2011/Jun

In case you missed the link in the section above, there is a straw poll at Wikipedia talk:WikiProject Mathematics/Straw poll regarding lists of mathematics articles which is scheduled to end during June 2. — Carl (CBM · talk) 01:35, 26 May 2011 (UTC)

• This straw poll is set to end in about two hours - anyone else wishing to opine, speak now or forever hold your peace! bd2412 T 04:17, 2 June 2011 (UTC)

The straw poll at Wikipedia talk:WikiProject Mathematics/Straw poll regarding lists of mathematics articles has closed with a consensus to move the lists of mathematics articles to project space. I have implemented this consensus, and I have temporarily retargeted all redirects from mainspace to the new page locations in project space; these cross-namespace redirects will eventually be deleted, unless the project opts to set up some non-maintenance lists at the original article titles. In retrospect, although this idea was not raised before, I don't think anyone would object to these being in Portal space either, which might be the most natural fit if you want people to be browsing them. Cheers! bd2412 T 02:01, 3 June 2011 (UTC)

I was proposed three or four years ago to move it to the portal space. Everyone opposed it except the person who proposed it, and he went ahead and moved it anyway. I moved it back, after pointing out that the consensus was for not moving it. But not before Oleg Alexandrov told me the consensus was for moving it. Oleg is too credulous sometimes. Michael Hardy (talk) 02:50, 3 June 2011 (UTC)

Is the move to project space the reason why Jitse's bot has not done the most recent update of the list of new articles at Wikipedia:WikiProject_Mathematics/Current_activity? "bd2412", have you communicated with Jitse Niesen about this? If not, then do so. Fast. Michael Hardy (talk) 02:54, 3 June 2011 (UTC)

Have you looked at Jitse's page to see whether I communicated with him about this? bd2412 T 03:01, 3 June 2011 (UTC)

I apologize for the snarkiness of that response. Yes, I have communicated the situation to both Oleg and Jitse. If it takes a day or two for bot maintenance to get back up to speed, no irreversible harm will come of it. If there is anything I can do to assist in the interim, please let me know, as I will be around. Cheers! bd2412 T 03:06, 3 June 2011 (UTC)

Arithmetic surface is a new article that could use some work. I've put a "no intro" tag on it. The only category it's in is Category:Arithmetic; probably at least one other should be there. Michael Hardy (talk) 02:00, 31 May 2011 (UTC)

This is a reasonable test case for the idea that we should make at least the lead section accessible to non-experts. If what I have added falls between two stools (the usual hazard), could we at least discuss it at Talk:Arithmetic surface? Such remarks have in the past been cut out of leads, in my experience, but the onus really should be on those doing that to do better. I don't really want to hear that basic heuristics are OR. Charles Matthews (talk) 08:15, 4 June 2011 (UTC)

Editor Stochastikon-bernoulli (talk · contribs) has recently created the following series of new articles:

• Bernoulli space
• Bernoulli stochastics
• Causal thinking
• Ignorance space
• Quantification of randomness
• Random structure function
• Reliability level
• Stochastic measurement procedure
• Stochastic prediction procedure
• Stochastic thinking
• Variability function

(there may be more), all of which have few or no sources outside of the works of one Prof. Elart von Collani, and all of which contain links to the web site of Prof. Collani's company Stochastikon. The coincidence of user name and company name suggests at least a conflict of interest; there may be concerns about the notability of some of these topics or the narrowness of the sources; and this may be an attempt to promote Prof. Collani, his books and his company via Wikipedia articles. I have placed a note about these concerns on the editor's talk page. Any thoughts ? Gandalf61 (talk) 08:26, 3 June 2011 (UTC)

There are 11 articles listed as created by the editor, so your list seems to be complete. Bernoulli stochastics especially sticks out because it's basically the name of the editor switched around and it seems to be an OR invention/concept the editor is trying to push. The other articles I looked at seemed rather essay-like though statistics is not my area of expertise. I'd say COI is a reasonable conclusion.--RDBury (talk) 10:25, 3 June 2011 (UTC)

The Logarithm article was recently promoted to Featured Article so congratulations to the folks that made that happen. It is our first FA in two years, a long time considering we once averaged an FA every 2 months.--RDBury (talk) 10:02, 3 June 2011 (UTC)

True. As the nominator I now also know better why there are few FA's: pushing an article to FA level is usually fun, pushing it through the FA process is quite time-consuming and requires a fair amount of patience to satisfy those reviewers who like to nitpick about MOS aspects and the like.

Please note that the article will be on the main page on Sunday (June 5th). A few math guys watchlisting this would be good, I think. (I will be unavailable during most of the day.) Jakob.scholbach (talk) 16:42, 3 June 2011 (UTC)

Yes, FA seems to be about meeting meaningless requirements rather than improving articles. MY experience with Wikipedia:Requests for feedback has been much better.

It's good that you were able to make it through the process, but I doubt I would have the patience.

CRGreathouse (t | c) 19:46, 3 June 2011 (UTC)

Don't be polemic. If you disregard the MOS folks I think you can get some very good feedback. Personally, if an article is aiming to be among the best I rather invest the time needed for a serious review at FAC than at intermediate levels like GA, Peer review, or RfF. But I agree the process is a pain, wouldn't go through it either. Nageh (talk) 20:23, 3 June 2011 (UTC)

I'll change my views as soon as I see a FAR on a math article where at least a quarter of the suggestions are content-related. Until then... CRGreathouse (t | c) 20:44, 3 June 2011 (UTC)

CRG is right: very few reviewers are able to judge whether a math article is comprehensive and factually correct. I don't consider the review process as meaningless, though. My experiences are this: the quasi-totality of reviewers has the best intentions. Most of them are lay people (much the same way I'm a layman in almost everything). Interested, positively tuned lay reviewers do help the articles become more easily understandable; a few, on the other hand, have unrealistic or unactionable expectations as far as the accessibility of "technical" articles is concerned. Another kind of review that I often find problematic is people just reviewing the lead section of an article.

Instead of whining more :) I'd like to urge people around to participate in FA reviews. The FA review process seems to be run by a rather small group of regular reviewers. Having reviewers well-accustomed to the FA criteria is not bad, but WP will also benefit from a broader input for FA's, especially when it comes to scientific topics most people are scared of. Jakob.scholbach (talk) 21:31, 3 June 2011 (UTC)

I did not mean to imply bad faith on the part of the reviewers. CRGreathouse (t | c) 01:13, 4 June 2011 (UTC)

FAC is not really the venue for comments on content. That is typically what peer review/projects are for. The difference between a good article and a featured article is not in the content, but in the presentation of that content. When articles reach FAC they are usually pretty OK contents wise. A lot of the reviews focus on presentation, which for technical articles means a lot of talk about accessibility, etc.

In my experience with FACs both for this project and for physics is that articles come out of the process a lot more polished.

As to the latest abomination that was called the logarithm FAC. That seemed to be mostly a problem of a lot of run by reviewer that did not follow up on responses to their comments.TR 07:50, 6 June 2011 (UTC)

I've created a new article titled Integral of the secant function, mentioning that

• It was first calculated numerically in the 1500s for the purposes of cartography;
• Its closed form was a well-known conjecture from the 1640s until the 1660s;
• The conjecture was proved by Isaac Barrow;
• The proof was the first use of partial fractions in integration.

As usual, further work should include at least these two things:

• More work within the article;
• More links to the article if appropriate. (Currently eight other articles link to it.)

Michael Hardy (talk) 02:11, 6 June 2011 (UTC)

Wouldn't it be better to create a secant article, with this as part of it?TR 05:48, 6 June 2011 (UTC)

I'm not sure what else one would say about the secant function. If the content were to be moved, I think it would make more sense to put it under partial fractions in integration. But I don't see a problem with it existing as an independent topic, it looks notable enough. Jowa fan (talk) 06:51, 6 June 2011 (UTC)

I'd like to get a second or third opinion on whether it would be worthwhile to add links to Khan Academy to relevant articles. It's a non-profit which produces short educational videos delivered through YouTube. Many of them are math related, usually high school or middle school levels. I think Introduction to Functions makes a good example. The style is informal, some might say extemporaneous, but they might provide an answer for those who complain that you can't actually learn a subject from a WP article. I checked WP:ELNO and I think it meets the criteria, but some confirmation would be nice. A couple of articles (e.g. Integral) have already been done. If it's is deemed worthy then the next step would be to create a template for the site.--RDBury (talk) 09:42, 5 June 2011 (UTC)

Well they are definitely suitable for external links and if many authors start using a template might be useful (though imho not necessary). The only thing I might be a bit wary about is a mass adding of it and replacing other suitable links by it. Khanacademy has the advantage of being relatively well known by now, but principally I'd treat it as any other good learning site or private math site (the huge of number of them out there).--Kmhkmh (talk) 10:07, 5 June 2011 (UTC)

The videos seem to provide a good complement to what Wikipedia does so they're fine by me. Most of the maths sites I've seen are just rubbish doing practice in addition with a pile of ads so I'm very glad to see this one giving a good service. Dmcq (talk) 15:47, 6 June 2011 (UTC)

Could someone perhaps have a look at this article? It looks fine, just that it cites a huge amount of publications from what seems to be the article creator. Perhaps justified, perhaps a bit of self-promotion, I don't know enough about this to judge. --Crusio (talk) 14:34, 6 June 2011 (UTC)

It looks a little odd to me, but I can't tell whether that's because the author is not a fully fluent English speaker or because he's engaging in self-promotion. I suspect the latter, but I don't know any numerical analysis so I'm not a good judge. Can someone familiar with numerical PDEs help? Ozob (talk) 23:34, 6 June 2011 (UTC)

It looks like all the references are to primary sources except for one textbook by the same author. The cite doesn't give a page number and it seems like it's only given as general reference on FEM's, not the subject of the article. So imo it fails to meet notability guidelines, even if you ignore conflict of interest issues.--RDBury (talk) 00:44, 7 June 2011 (UTC)

The user is responsible for a number of new pages:

1. G space
2. Weakened weak form
3. Smoothed finite element method

He's also made contributions to meshfree methods, functionally graded material, and finite element method, but those articles existed before him and they cite secondary sources. None of the ones he's created do (except for his own textbook). I think they should be prodded for lack of notability. Any objections? Ozob (talk) 10:58, 7 June 2011 (UTC)

In Ellipse#Circumference, an anon has changed the formula for the circumference of an ellipse from ${\displaystyle C=4aE(e)}$ to ${\displaystyle C=4aE(e^{2})\,\!}$. Since there is no edit summary and since the old formula has been there for at least two years, I reverted the change. Can someone who knows make sure this is right? Thanks. Duoduoduo (talk) 14:26, 9 June 2011 (UTC)

You were right to revert. I think I've come across this before, perhaps there is some book or site with it wrong somewhere Dmcq (talk) 14:56, 9 June 2011 (UTC)reversion was right

It seems to me that these cannot pertain to an equalizer. Is it just me? — Kallikanzarid^talk 19:54, 9 June 2011 (UTC)

They look correct to me. However, they are not diagrams of equalizers. Ozob (talk) 20:04, 9 June 2011 (UTC)

I got it now, it's just that zero morphisms absorb other morphisms. This should be mentioned in the article, IMO. — Preceding unsigned comment added by Kallikanzarid (talk • contribs) 00:00, 10 June 2011 (UTC)

Four new articles, Circle packing in an isosceles right triangle, Circle packing in an equilateral triangle, Square packing in a square, Circle packing in a circle, basically lists of optimal packings of geometrical shapes, were recently created. My feeling is that these lists were borderline WP:IINFO when they were in Packing problem, the article from which they were taken. So creating separate articles for them raises notability issues as well as opening the door for articles on similar dubious subjects. Any thoughts? (I'm adding Notability tags for now.)--RDBury (talk) 10:16, 2 June 2011 (UTC)

What kind of literature is there to back up such articles? If such problems are rarely treated separately from more general packing problems, there is little reason for separate pages. Tkuvho (talk) 11:46, 2 June 2011 (UTC)

I think this information is good to have in Wikipedia and not indiscriminate information. But there's no need to break them out into individual articles as far as I can tell. CRGreathouse (t | c) 14:46, 2 June 2011 (UTC)

I expanded the circle packing in an equilateral triangle article based on five different published journal papers about that specific problem (two of which concern an Erdős conjecture about it). I think that's enough to justify its separate existence, at least. —David Eppstein (talk) 17:21, 10 June 2011 (UTC)

Sounds good. CRGreathouse (t | c) 19:00, 10 June 2011 (UTC)

There is a new discussion about notability of Boubaker polynomials, the article were deleted here and at many other projects due to lack of notability. I hope someone could help me about this. I'm not sure how should I evaluate the notability of this article and what notability criteria should be used for such articles. the page currently exist at Turkish, Chinese and Arabic Wikipedia and some users trying to create/restore it on other projects too. please take a look at sources at Wikiversity and Turkish Wikipedia, apparently there are more pages on the web referring to "Boubaker polynomials" than back in 2009. in short, I want to know does Boubaker polynomials meets English Wikipedia policy or not?   ■ MMXX  ^talk  18:18, 4 June 2011 (UTC)

They're not considered notable by the standards of the English Wikipedia; other projects can do as they wish. The polynomials are a simple re-invention of a special case of Chebyshev polynomials; their "interesting properties" are essentially just those inherited from the Chebyshev polynomials. CRGreathouse (t | c) 19:13, 4 June 2011 (UTC)

The user is trying to restore the deleted article at Farsi Wikipedia and their policy is almost same to English Wikipedia, I just find this discussion too.   ■ MMXX  ^talk  19:35, 4 June 2011 (UTC)

According to Wikipedia:Sockpuppet investigations/Mmbmmmbm/Archive some of the accounts behind the repeated attempts to include this material have been globally blocked from all wikimedia projects for cross-project sockpuppetry. I don't know the procedure for requesting new attention on the case but perhaps whoever is behind the wikiversity and Turkish and Farsi cases should be brought to the attention of the people who do global blocks. —David Eppstein (talk) 20:08, 4 June 2011 (UTC)

At this point, even if it were considered notable, the further generalization from one of the sources would be even better. And they're not called "Boubaker polynomials". A section of Chebyshev polynomials would be all that would be appropriate, even for that concept. — Arthur Rubin (talk) 22:52, 4 June 2011 (UTC)

From this and this It is clear that the problem began between a FR:WP administrator and an obstinated user. The FR:WP administrator who initiated the earliest AFD in fr:WP and EN:WP... (who is now banned for abuse and racial issues) was,as he declares frankly and proudly :Motivated by Hatered, Racim an Vengence!!:(according to his own speach on his own page: )

The FR:WP administrator :

• Initiated AFD on several WP claiming NOT-NOTABILITY (cross-wiki).
• Vandalised the page by erasing sources,and was each time inserting nonsense sources and bloking any positive correction.
• Lobbying some users who intervened without even knowing the subject (see his talk pages)

Now the page could have been considerd as an encyclopedical one ONLY when a securised copy has been provided(far from this users' vandalism, He tried desparately to delete it, he was TERRIFIED that people could see the relevant, verifiable and independent sources!!! See his ridiculous attempt to delete it !!a miserable begging for deleting a page!!)

Hi!, Now everyone in intersested in the persons but not in the matter: The existing sources in the securized page are clearly, obviously and verificably in concordance with Notability in Wikipedia; so what is the remaining problem, and what is the real motivations of users wanting desparately to kill this page?? , not difficult to guess --Techala (talk) 09:33, 6 June 2011 (UTC)

I wonder why you're trying so hard to promote this article by using multiple accounts in many projects in different languages! you just copied everything that you said on my talk page in Farsi Wikipeida here too, and you are attacking other editors by falsely accusing them as you did on my talk page in Wikimedia Commons. please notice that the related WikiProject can make the final decision whether an article is up to our standards or not, this discussion have been raised here many times and community decision was that your article is not notable by the standards of the English Wikipedia.   ■ MMXX  ^talk  10:05, 6 June 2011 (UTC)

I have opened a new sockpuppet investigation at Wikipedia:Sockpuppet investigations/Mmbmmmbm. Ozob (talk) 10:53, 6 June 2011 (UTC)

User:Techala and User:Balakyo (below) have been blocked. Ozob (talk) 23:30, 6 June 2011 (UTC)

• That is wonderful!! the page of the so-called Boubaker polynomials is just DELETED from ARAB wikipedia after a four-years resistance !!

After instructions message from   ■ MMXX to ar.wikipedia.org/wiki/مستخدم:Abanima:

• This deletion from ARAB wikipedia is a good warning against any future ARAB fellow who dare claiming any notability or overdue weight in other wikis. Congratulations.

--Balakyo (talk) 20:40, 6 June 2011 (UTC)

Don't worry, it has been rescued and is now safely tucked up in ProofWiki where it won't get deleted for any arbitrary reason. --Matt Westwood 21:06, 6 June 2011 (UTC)

No No Matt Westwood, you shouldn't. These things are not notable at all, they aren't present in any valid source and they are a declinaison of Chebyshev and their mathematical value is quite miserable.

By allowing this rescue you may encourage other arabs to infest latin and francophone wikis. Take an example from the french wiki and the incident there .--PoPo Le Chien Contrib (talk) 03:03, 7 June 2011 (UTC)

So who made you God? Who allows you to tell the whole world who is or is not allowed to edit a wiki? If you're typical of wikipedia editors I hope this site destroys itself. --Matt Westwood 09:41, 11 June 2011 (UTC)

I had a look at that wiki and it was set up by a user called 'Prime mover' there. Interestingly Wikipedia used to have a user called Prime mover but they were indefinitely blocked in 2006, I don't know why as can't even see what they tried to contribute. Anyway I only hope Proof wiki doesn't get plagued by vandals and people hungry to have their name in lights and idiots with a mission to fulfil like Wikipedia has. Dmcq (talk) 09:35, 7 June 2011 (UTC)

Don't worry, vandals get blocked - forever. --Matt Westwood 09:41, 11 June 2011 (UTC)

We need to stay focussed on whether the topic is notable. It doesn't matter what country a contribution comes from. People of any nationality are welcome to contribute to this wiki as long as they respect the policies here. Jowa fan (talk) 04:07, 7 June 2011 (UTC)

• I disagree with Jowa fan, a tpoic with an arab name could be of relevance in Arabic Wikipedia but never in latin or francophone Wikipedia.--PoPo Le Chien Contrib (talk) 08:47, 7 June 2011 (UTC)

An English language wiki should never allow someone to contribute with such a stupid name as PoPo Le Chien. Stupid mutt. --Matt Westwood 09:41, 11 June 2011 (UTC)

Wikipedia:Sockpuppet investigations/Mmbmmmbm again. Ozob (talk) 10:47, 7 June 2011 (UTC)

While doing some miscellaneous edits on Matsumoto's theorem (group theory), I came across the term natural map, and linked to it, and found it to be a red link. So I redirected it to natural mapping, and then looked at that, and found that "The real function of natural mappings is to reduce the need for any information from a user’s memory to perform a task. This term is widely used in the areas of human-computer interaction (HCI) and interactive design.[1]". So I left the redirect intact but directed the link from "natural map" within the article to natural transformation.

So some questions arise: Should we move "natural mapping" to "natural mapping (somethingology)" and redirect "natural mapping" to something else, or create some new disambiguation page, or what? And what should I have linked to? Michael Hardy (talk) 04:53, 11 June 2011 (UTC)

It's pretty clear that the term "Natural map" should be linked to "Natural transformation" when used in a math article. The current "Natural mapping" article is basically an orphan so I don't think there would be too much objection to moving it to Natural mapping (interface design) and creating a dab page. We should cross post this to Wikipedia talk:WikiProject Graphic design as a matter of etiquette though.--RDBury (talk) 10:10, 11 June 2011 (UTC)

Update: I've made natural mapping into a disambiguation page after moving natural mapping to natural mapping (interface design). I fixed the links to natural mapping so that they point to the latter article. Nothing (in the article space) except redirects now links to natural mapping. Michael Hardy (talk) 01:58, 12 June 2011 (UTC)

Numerical Analysis (book) is about the book by Burden and Faires. It's a complete orphan: no other articles link to it.

Now it is nominated for deletion. Opinions? Michael Hardy (talk) 05:02, 11 June 2011 (UTC)

While reviewing WP:NBOOK for this is struck me that that guideline does not really apply to textbooks, for example it talks about literary awards and being used as a movie plot. So for math books it seems to me that the fallback WP:GNG should be used. Are there considerations for math/technical books not covered in the GNG?--RDBury (talk) 10:21, 11 June 2011 (UTC)

I think WP:NBOOK does gives us something to go on. Under the heading "coverage notes" we see the phrase "this guideline may be instructive by analogy". The fifth criterion can apply to academic books with no problems. For criterion 1, it ought to be clear that book reviews in mathematical journals (not necessarily for a general audience) are worth something. For criteria 2 and 3, there exist awards for mathematical exposition, and it's possible for a textbook to have significant impact in its field. There's also a paragraph Wikipedia:NBOOK#Academic_books. But yes, it would be nice to have a little more detail on the page. There's some inconclusive debate at Wikipedia_talk:Notability_(books)#Proposed_revision_to_criterion_.233_language. Jowa fan (talk) —Preceding undated comment added 13:07, 11 June 2011 (UTC).

On a tangent to the recognized content section above, which focuses on Featured Articles, I was wondering if members of this project had considered the potential for Featured Lists? At the moment there are three FLs under this project's banner, but all of them are people and/or event oriented. To my knowledge, there are no Featured Lists that focus on mathematics. Looking through Category:List-Class mathematics articles, I believe that there is the potential for some fantastic ones that do focus on the subject itself. I also feel that some topics actually lend themselves better to a list format than an article one. For instance, a merger of Prime knot and List of prime knots (renamed Prime knots) might improve our overall coverage of the subject, as well as setting the ground work for a future push towards featured status.

Now that Today's Featured List is up and running, there would also be the potential to get a maths list on the main page, exposing the work to the millions that visit the page every day. As someone heavily involved with TFL, I can say with certainty that a list based on a mathematical concept would be looked upon very favourably there.

It's undeniable that Featured Lists do place a degree of emphasis on presentation. The main thing to worry about is writing a well-sourced lead that introduces the topic. Beyond that, I would be very happy to take responsibility for all the minutiae of reference/table/image formatting. I wouldn't be seeking a co-nomination for the work: I'm simply determined to play my part in diversifying our selection of FLs. Feel free to drop me a note on my talk page if you might be interested in taking up the offer.

I hope to see some of you at WP:FLC in the future. Warm regards, —WFC— 15:22, 14 June 2011 (UTC)

Lists of mathematics topics is a former Featured List, as you will find if you look at Talk:Lists of mathematics topics.

It is definitely one of the best things ever done on Wikipedia. I think of it as not primarily for navigation, but for browsing, i.e. looking around to see what's out there that you hadn't thought of. It lost its featured status because of a lack of references. The references are in the articles ultimately linked to, two clicks away. I'm not sure how to compile references for a thing like this. It fits no genre; it is unique in the whole history of the printed word. It differs from things like the AMS subject classification system in including things like the list of factorial and binomial topics, the list of circle topics (each of those is fascinating in itself!), and there's lots of stuff like that. Michael Hardy (talk) 18:34, 14 June 2011 (UTC)

Lists of mathematics topics is indeed a fantastic resource. I've sought extra opinions on what would need to be done to restore it to featured status. Although I couldn't help but notice that List of mathematics topics redirects to a different article, which is a bit confusing. —WFC— 23:11, 14 June 2011 (UTC)

Addressing a more important point than what I addressed above: Lists within the scope of this particular WikiProject are among the best on Wikipedia, or for that matter within all of history. (Yeah—I know—you're going to say that's a hyperbolic exaggeration. But really. Wikipedia is truly unprecedented, and I don't think there's actually any exaggeration in this instance. 'nother words, I agree with the original sentiment here. Michael Hardy (talk) 03:31, 17 June 2011 (UTC)

Hey there! I'm from WP Elements, and we want to start using Bplus-class for our articles, but without any idea how to introduce it. I noticed you use it, so could you help us to do it? Help is surely appreciated--R8R Gtrs (talk) 09:36, 16 June 2011 (UTC)

Imo we should be phasing B+ out in this project. Math guidelines are a bit less stringent than most projects, so a B+ here corresponds roughly to a B elsewhere. The fact that we have our own guidelines when nearly every other project uses standard WP 1.0 guidelines causes confusion for people for other projects who want to add our banner to an article. So unless you have a really compelling reason that your project needs to be a maverick and have different standards then everyone else, I'd say you're better off forgetting about the idea. I think the reason we're different is we were one of the first projects created, before there was much of a standard to go by, and since then inertia set in.--RDBury (talk) 10:51, 16 June 2011 (UTC)

The Monty Hall problem article, one of our longest standing featured articles, has been delisted. From what I gather this was due to long-standing and apparently unresolvable editing disputes, see Wikipedia:Featured article review/Monty Hall problem/archive3 for the full discussion. I'm also a bit surprised that until now this hasn't appeared either here or on the article alerts page. (Correct me if I'm wrong, though I do try to keep an eye on both.) Any ideas on getting the article relisted?--RDBury (talk) 20:00, 16 June 2011 (UTC)

Currently, Equivalent norms redirects to norm (mathematics), which doesn't describe norm equivalence. Is there a better article for it to redirect to? — Kallikanzarid^talk 23:00, 16 June 2011 (UTC)

Aren't they described in Norm (mathematics)#Properties, or did you mean something more specific? Thenub314 (talk) 23:05, 16 June 2011 (UTC)

OK, now Equivalent norms redirects to Norm (mathematics)#Properties. Does that solve the problem? Jowa fan (talk) 02:49, 17 June 2011 (UTC)

Yeah, thanks. Looks like it was my poor eyesight :( — Kallikanzarid^talk 04:22, 17 June 2011 (UTC)

The file File:Sine Cos Proofs.pdf has recently come up at WP:FFD. There may well not be a place for this file on WP; but it does seem rather a more useful self-contained take-away than the section of our current omnibus article Proofs_of_trigonometric_identities#Angle_sum_identities, which there might be a case for breaking into smaller self-contained chunks. Jheald (talk) 21:57, 8 June 2011 (UTC)

We've had many long discussions here on how an whether proofs should be included on WP, the results are given in Wikipedia:WikiProject Mathematics/Proofs. Keeping that in mind, "Proofs of trigonometric identities" is not exactly an example of the what proofs should be in WP and how they should be presented. It might be split up and incorporated into a wikibook on trigonometry, but to me it's not an encyclopedia article.--RDBury (talk) 07:30, 9 June 2011 (UTC)

I have to say I utterly disagree.

In my view "trignometric angle sum identity" is an appropriate topic for an encyclopedia; and in the context of treating such a topic in an encyclopedic way we should be trying to convey not just that there is an identity that exists, but also an instinctive understanding of why the identity exists -- including how it can be related to a geometric construction; how it follows directly using Euler's formula and considering real and imaginary parts; and how it follows directly from matrix multiplication (the last two of course being very closely related, but that is an additional bit of understanding). Proofs for the sake of proofs are not appropriate; but that sort of instictive understanding of why is something we should be aspiring to in a potential topic like this; and, indeed, for any mathematical topic for which we can provide it. Jheald (talk) 08:38, 9 June 2011 (UTC)

Compare for example the Wolfram article. Jheald (talk) 09:09, 9 June 2011 (UTC)

We have Angle sum identity which is, at the moment, a redirect. Perhaps it is a topic which should be expanded to an actual article, assuming that the material isn't already somewhere else that I missed. Proofs are good if they are sourced and have encyclopedic value. Unfortunately many proofs we have here unsourced exercises in algrebra/calculus/geometry and much of what I see in "Proofs of trigonometric identities" falls under the latter category. In many cases, if a reason "why" should be added for an identity/theorem, it can be incorporated into the exposition rather than separated out as a formal proof.

We probably shouldn't be using MathWorld as an example either. Overall it's a good resource but it also has a lot of material that isn't encyclopedic by WP standards.--RDBury (talk) 11:46, 9 June 2011 (UTC)

I agree that the exposition is the important thing, and that most of the time setting things out in the shape of a formal proof is probably not appropriate for us, unless that really is the most effective way to get the "why" background across.

I'm curious about your comment about Mathworld. That article on Trig addition formulas seemed entirely in keeping with how we might give an article here. I'm not particularly familiar with Mathworld more widely, but is there anything in that particular article you would view as non-encyclopedic? (And why?) Jheald (talk) 12:10, 9 June 2011 (UTC)

What I meant was that in general we shouldn't be using a MathWorld article as a example of what a WP article should look like. There have been many discussion here on MathWorld, just do a search in the archives. One that comes to mind for me is Wikipedia talk:WikiProject Mathematics/Archive 65#Missing science topics, the issue was basically there are many MathWorld articles where the subject does not meet WP:GNG criteria.--RDBury (talk) 15:19, 9 June 2011 (UTC)

It isn't just notability, unless that word is stretched pretty far. My biggest issue with MathWorld is actually neologisms. My impression is that it more or less makes up words, or repeats terminology used in a nonce sense as though it were accepted and standard.

Now, there's nothing wrong with making up words — mathematicians do it all the time. But they do it in research papers, and the new term is either picked up by others, or it isn't. Encyclopedias are in a different position and really should not make up words. Since MathWorld claims to be an encyclopedia, this is a very serious flaw. --Trovatore (talk) 23:20, 19 June 2011 (UTC)

Pickands–Balkema–de Haan theorem is a complete orphan: No other articles link to it. Work on it! Michael Hardy (talk) 03:27, 17 June 2011 (UTC)

Um, well, OK, if you say so. It was trivial to create three useful links, I'm not sure why you couldn't have done it yourself. But perhaps people who actually know something about statistics will be able to contribute more here. Jowa fan (talk) —Preceding undated comment added 04:51, 17 June 2011 (UTC).

Just that there are only 24 hours in a day...... Michael Hardy (talk) 16:59, 17 June 2011 (UTC)

I found constructive ordinal to be a red link, so I've redirected it to ordinal notation and labeled it a "redirect with possibilities". Should we have an article with this title? Michael Hardy (talk) 04:47, 19 June 2011 (UTC)

The redirect seems like the best choice; a constructive ordinal is just going to be an ordinal notation in the end. I don't think it's worth starting a separate article. — Carl (CBM · talk) 12:04, 19 June 2011 (UTC)

There is a nothingness and the empty set discussion at the Nothingness article. That article can use a lot of improvement as to both content and sources. PPdd (talk) 15:01, 9 June 2011 (UTC)

LivingBot is adding a number of dubious tags to some article talk pages, such as this . Does anyone know about this? I'm inclined to revert... Jakob.scholbach (talk) 19:33, 20 June 2011 (UTC)

I've come across this "Betascript Publishing" before, I think they are people who take wikipedia articles package them as a book and sell them on amazon. I think the bot might be tagging articles that have been so packaged to indicate that these articles are not copyright violations, rather a published book copied their content. But this is all guessing. I do find the tag annoying though. RobHar (talk) 20:01, 20 June 2011 (UTC)

There is a recent long discussion on this and related issues: Wikipedia:Village pump (policy)/Archive 87#Wikipedia articles being sold by book companies. This is a growing trend to and somewhat unscrupulous since these publishers sell the books to unsuspecting people. Apparently it's legal as long as you put a link to WP somewhere in the book, even if you don't put it anywhere that's accessible on Amazon of Google Books. It's going make detecting things like circular referencing and copyright violations more and more difficult in the future. Tagging talk pages is supposed to help but I'm not sure what good it will do since if the trend continues (both profitable and legal so I expect it will) a large number articles will end up being published this way. The good news is that most of us will be "published authors" pretty soon.--RDBury (talk) 21:47, 20 June 2011 (UTC)

It strikes me as a reasonable way of handling an unpleasant situation. I don't see any problems with the tags remaining there. Jowa fan (talk) 01:11, 21 June 2011 (UTC) (revised opinion below)

Ah, I get it. That wasn't quite clear to me from the tag itself. Anyway, the only way to turn this into a less pleasant situation in the long run might be to have WP articles that are good enough so that respectable publishers publish them in a reasonable way. Jakob.scholbach (talk) 06:41, 21 June 2011 (UTC)

I take it back. Given the number of such books appearing (see table at VDM Publishing, currently about half a million titles), it won't take long to tag every single Wikipedia page. So we should probably try and stop the tagging before it gets out of hand. Jowa fan (talk) 07:18, 21 June 2011 (UTC)

There's some discussion at Wikipedia:Bots/Requests_for_approval/LivingBot_17#Review Jowa fan (talk) 07:35, 21 June 2011 (UTC)

This kind of spam seems to have finally reached the level where Amazon can no longer ignore it. So hopefully we will soon see an end of this nonsense. Hans Adler 08:41, 21 June 2011 (UTC)

These things tend to be like whack-a-mole; if Amazon stops it then they'll pop up on Nook and Google Books. E.g. our Fibonacci number article was copied into books on sale at Google books here ($15.63) and here ($9.99). But people don't stop using e-mail because of e-mail spam and I expect it will be similar with this kind of spam; filters will be put in place and spammers will find ways around them, but people will put up with it because downloading a book at home is a lot easier than schlepping to the local bookstore. For WP editors I think it will mean more going to the library instead of looking stuff up on Google, in other words we need to add spam filters of our own. In the first example, the book has an ISBN number, has a 2005 copyright (before the content appeared on WP) and has links to buy at Barnes&Noble and Borders. The give-aways are that the content has little to do with the title, it's written WP's trademark summary style, and the sections begin with the Math Project's "In...". Obvious to a WP editor but it's hard to see how an automated filter would pick up on it.--RDBury (talk) 15:10, 21 June 2011 (UTC)

Google recently changed their ranking algorithm to penalize "content farms", sites with very low quality content that are mostly filled with ads. It seems to have worked, because one big content farm just had to lay off 10% of their staff . Now content farmers seem to be moving into ebooks . If Amazon and Barnes and Noble penalize farmed ebooks, then they won't be profitable, either. The people who publish these "books" only do it because it's profitable, and if it isn't, it won't be long before they vanish. (When was the last time you saw a Wikipedia mirror at the top of a Google search?) Ozob (talk) 00:08, 22 June 2011 (UTC)

To avoid fractured discussion, please continue at Wikipedia:Bots/Requests_for_approval/LivingBot_17#Review rather than here. Thank you LeadSongDog come howl! 04:32, 23 June 2011 (UTC)

I was prompted by some recent off-wiki email (asking me for advice on getting started with Wikipedia editing) to write an essay on Wikipedia editing for research scientists. It's in my user space for now but it seems reasonable to move it to Wikipedia essay namespace at some point. Any feedback would be welcome. —David Eppstein (talk) 17:27, 21 June 2011 (UTC)

Are you aware of this paper? I know some of the people involved. Seems to be well thought through. Charles Matthews (talk) 21:02, 21 June 2011 (UTC)

I wasn't aware of it, no. Looks quite helpful — thanks for the pointer. —David Eppstein (talk) 21:08, 21 June 2011 (UTC)

Mention using your watchlist and, in particular, putting appropriate project talk pages on it. JRSpriggs (talk) 08:46, 22 June 2011 (UTC)

Done, thanks. I've now moved this into Wikipedia namespace: Wikipedia:Wikipedia editing for research scientists. —David Eppstein (talk) 00:36, 25 June 2011 (UTC)

The new article Horn angle, is basically a DICDEF with inaccuracies (see the talk page). There is an obsolete term translated as Cornicular angle, or horn-like angle and Heath gives more than 3 pages of material on it (in small print) in his commentary on Euclid Book III Prop. 16. Mathworld also has a "Horn angle" article which has more modern references. I'd like to either change the article to a summary of Heath or change it to a redirect if no one thinks it's worthwhile.--RDBury (talk) 14:37, 23 June 2011 (UTC)

Does seem important enough for an article, although I guess it is more of an obscure historical issue than anything else. There are slightly longer discussions at and but without doing more reading I couldn't really confirm or deny my first impression that various people asked questions about whether this kind of "angle" makes sense, and that noone really gave much of an answer. Kingdon (talk) 23:25, 23 June 2011 (UTC)

There is a new weekly section on the main page called "Today's featured list" and I have nominated List of winners of the Mathcounts competition to have a spot here. There has been some opposition to the nomination and it looks like the list could become a removal candidate very soon unless the quality of the list is improved. If you are interested in maintaining the list's featured status and seeing a summary of it up on the main page, your help in improving the article would be greatly appreciated. Neelix (talk) 03:37, 25 June 2011 (UTC)

A new article titled Charles Paul Narcisse Moreau, created by user:r.e.b., is one of the more unusual biographical articles, in that identification of the person seems to be a moderately intractable problem, and the intractability itself seems somewhat well-documented. These three people seem to be known to have existed:

• A French military officer who organized a course of instruction on artillery and did various other things;
• A mathematician who introduced Moreau's necklace-counting function and wrote various other papers;
• A Colonel Moreau who is renowned as one of the losingest players ever in tournament chess, who lost all of the 26 games he played at a tournament in Monte Carlo in 1903.

The question is: Are all three the same person? Considerable circumstantial evidence that these three are the same has been published.

In the unlikely event that somebody knows something, could they further edit the article accordingly? Michael Hardy (talk) 23:50, 24 June 2011 (UTC)

There's a bit more here; NB that the later items are presumably a different Charles Moreau. CPM Moreau is at Calais in one case. May need specialist research. Charles Matthews (talk) 08:50, 26 June 2011 (UTC)

The introduction of the article seems to say that the Ricci tensor is symmetric for all pseudo-Riemannian manifolds. In a book I'm reading at the moment, it says that an affine connection ∇ with zero torsion has symmetric Ricci tensor if and only if ∇ is locally equi-affine. Where we call an affine connection locally equi-affine if around each point x of M there is a parallel volume form, i.e. a non-vanishing n-form ω such that ∇ω = 0. Which one is correct, the article or the book? It seems to me that there are some missing hypotheses in the article's statement. — Fly by Night (talk) 17:04, 25 June 2011 (UTC)

I think you are forgetting that for a pseudo-Riemannian manifold it is assumed that you use the Levi-Civita connection, which is always equi-affine. (The Levi-Civita tensor always is a parallel volume form for the Levi-Civita connection.)TR 20:10, 25 June 2011 (UTC)

But that's my point: it's not assumed; the Levi-Civita connection's not even mentioned until much later in the article. Reading the introduction, there's absolutely no reason to believe that ∇ is the Levi-Civita connection. Moreover, in general, it is not assumed that a connection on a pseudo-Riemannian manifold is the Levi-Civita connection. Take the book I linked to, for example. It would be a good idea to add this, and more detail to the article to avoid confusion. — Fly by Night (talk) 20:55, 25 June 2011 (UTC)

The Ricci tensor of pseudo-Riemannian manifold is by definition the Ricci tensor defined by the Levi-Civita tensor defined by the pseudo-Riemannian metric. It never is anything else, even when you calculate the Ricci curvature of some other connection on that manifold. As to the Ricci curvature article, it does (implicitly) say in the last line of the definition section that up till that point the Levi-Civita curvature had been assumed. Looking, at that article in general, not clarifying that earlier seems to be the least of its problems. As the article is currently written it is most likely useless to anybody that does not already no what the Ricci curvature is.TR 21:39, 25 June 2011 (UTC)

The Ricci curvature associated to a general affine connection is something that is only studied seriously by a very small group of people, whereas the Ricci curvature associated to a pseudo-Riemannian manifold is one of the most important objects in relativity theory and Riemannian geometry. I think it's appropriate to focus on these cases, and I have consolidated the discussion of the Ricci tensor associated to an affine connection to a short section at the end, since it doesn't seem appropriate to treat this in parallel with the classical Ricci tensor (the two have completely different properties, and are used for completely different things).

I agree that the article is not very good. I've tried in the past to improve it, but progress has been slow. There hasn't really been much wider input, and I've not really been willing to devote the time to get the article into satisfactory shape on my own. It seems from the discussion page that the article historically has been pulled in different directions by mathematicians of different stripes, and physicists. It might be helpful to have a constructive discussion at Talk:Ricci curvature. Sławomir Biały (talk) 22:03, 25 June 2011 (UTC)

TimothyRias: the definition of the Ricci tensor is relative to an affine connection; any affine connection. The Ricci tensor is defined as the trace of the curvature tensor, i.e. Ric(Y,Z) = trace{X → R(X,Y)Z}; and what is R well

${\displaystyle R(X,Y)Z=\nabla _{X}\nabla _{Y}Z-\nabla _{Y}\nabla _{X}Z-\nabla _{[X,Y]}Z\,.}$

If you're only interested in the Levi-Civita then that's one thing; but it's wrong to say that "the definition" of the Ricci tensor is with respect to the Levi-Civita connection. Sławomir Biały: Thanks for you edits to the article. But there still needs to be some mention at the beginning that we assume the manifold to carry its Levi-Civita connection. The article on pseudo-Riemannian manifolds does not make a big deal Levi-Civita connections either. It mentions some parallel with the Riemannian case, but also some big contrasts. It seems to be a very unnecessary assumption that most people hold; probably because of the way they leaned the subject. I'm not sure only a small number of people are interested. There has been a large increase in research involving projective, affine, equi-affine and centro-affine differential geometry over the last 20 to 30 years. — Fly by Night (talk) 22:49, 25 June 2011 (UTC)

I don't really think the Levi-Civita connection needs to be overly emphasized, but it's probably appropriate to mention it in the Definition section. There's a potentially greater risk of fuss over the curvature conventions. (Our sign convention for the Riemann tensor is the opposite that of Besse, which is used as a reference for the article, but our sign convention for the Ricci tensor is such that spheres are positively curved.) I've added text to resolve both issues I hope. Sławomir Biały (talk) 23:25, 25 June 2011 (UTC)

I've added a little footnote, but it doesn't look quite right next to the Harvard citation style. My footnote is indicated by a superscript number in square brackets. Not sure if you want to change the style… — Fly by Night (talk) 23:41, 25 June 2011 (UTC)

Discussion on the notability guidelines for specialized books, such as math or programming is going on at Wikipedia talk:Notability (books)#Criterion out of context. Some editors maintain that book that have not been covered in-depth in venues for a general audience, such as the New York Times, should be deleted from Wikipedia. However, recent AfD discussion on math and programming books ended up with such books being kept if they pass the less restrictive WP:GNG. I'm aware that every book in the Springer Graduate Texts in Mathematics, for instance, has probably been reviewed in some math journals, so passes GNG, but whether it passes NBOOK is open to interpretation. Please voice your opinion in that discussion. FuFoFuEd (talk) 01:24, 27 June 2011 (UTC)