Wikipedia talk:WikiProject Mathematics/Archive/2013/Nov

Is anyone willing + able to substantially revise or rewrite this article on compact spaces (topology)?

I turn to Wikipedia often for mathematics. I have found most of the articles to be excellent. However, I did not care for the article

http://en.wikipedia.org/wiki/Compact_space

While there may be some useful information in the later parts of the article and some good references, it gets off to a very bad start. If you are a mathematician and you read the first one or two sentences you will know what I mean. There are many valid complaints on the Talk page about its obvious flaws, and the author(s) seem to deny that there is anything wrong with the article. I do not have a lot of experience with editing Wikipedia, I do not know how it is determined who gets control over an article, but I hope there is someone out there with more Wikipedia experience, more time on their hands, and more expertise in topology who can improve this article. Gsspradlin (talk) 23:50, 30 October 2013 (UTC)

@Gsspradlin : You've formatted an internal link as if it were an external link, writing http://en.wikipedia.org/wiki/Compact_space instead of Compact space. If you're going to be editing Wikipedia articles, you should know about this. Michael Hardy (talk) 18:09, 1 November 2013 (UTC)

There is already an ongoing discussion on this subject at the bottom of Talk:Compact space#First paragraph. Sławomir Biały (talk) 23:57, 30 October 2013 (UTC)

It does seem rather odd that the lead paragraph gives the definition of sequentially compact rather than compact, especially since we already have an article for Sequentially compact space. Also that the correct definition was in the lead until about 5 years ago when someone changed it. --RDBury (talk) 02:55, 31 October 2013 (UTC)

Matrix analysis is now an article

Recalling this thread earlier this year, I thought to just create a stub for now. I don't have the time (and admittedly competence and inclination) to write the full article. Appreciation to anyone who contributes. M∧Ŝc²ħεИ_τlk 17:16, 2 November 2013 (UTC)

AfC submission

Hello again! Care to look at this and this? Thanks! FoCuSandLeArN (talk) 13:17, 24 October 2013 (UTC)

The second one seems like a very good article -- clearly a legitimate topic, not obviously plagiarized, generally informative and well written (though perhaps not uniformly in an encyclopedic style). --JBL (talk) 01:34, 25 October 2013 (UTC)

But what about the first one? It is a stub, and says so; it was approved for mainspace the 29th, and seems okay. I put several more WP:RS on the topic here -- Talk:Liénard–Chipart_criterion -- would appreciate it if somebody with expertise in mathematical-modeling control-system stability could take a look, and expand the article into something a bit more fleshed out. Thanks. 74.192.84.101 (talk) 20:45, 6 November 2013 (UTC)

Constants

Constant (mathematics) was briefly redirected to the disambiguation page constant, and then restored after it was discovered that the result left no good target for many of its links. Now it has been proposed instead to redirect it to variable (mathematics). Please contribute to the discussion at Talk:Constant (mathematics). —David Eppstein (talk) 07:07, 8 November 2013 (UTC)

Wikipedia talk:Articles for creation/Smith space

There seem to be a lot of mathematical submissions at the Afc this week. Here's another. —Anne Delong (talk) 23:51, 27 October 2013 (UTC)

This one has been created now. —Anne Delong (talk) 15:49, 9 November 2013 (UTC)

Wikipedia talk:Articles for creation/Dinesh Thakur

Dear mathematicians: This article about a number theorist needs some third party sources. I'm not sure what types of references a mathematician needs, but perhaps someone here can help. —Anne Delong (talk) 16:04, 29 October 2013 (UTC)

This one is in the encyclopedia now. Thanks! —Anne Delong (talk) 15:51, 9 November 2013 (UTC)

A couple general ideas

For accessibility. Whenever mathematical symbols initially appear in one of our articles, those symbols could be immediately followed by a written out version of a "spoken language" annunciation of those symbols. This is extremely helpful to a lay reader. Not only does it make clear the correct way to "say" the symbols, but it identifies each symbol by giving it a name, often instantly making clear the purpose/function/order/directionality of the procedure involved.

Re: Math levels. Since the evaluation of math level/difficulty is largely subjective and IMHO not specifically useful to the reader, as a lay reader of math articles, I would prefer our presentation of mathematics focus almost exclusively on accuracy and precision. Presentation hierarchy is self-organizing via links to other concepts, making precision and accuracy the essential components of "readability". The effort to clarify, for lay readers like myself by reducing or restricting the use of terminology and/or scope can have the unfortunate collateral result of inhibiting the ability of the mathematician writing the article to be precise and inclusively accurate. I agree the first line of the article should be a hip shot definition, as accurate and precise as a sound byte can be, or put conversely, as much of a sound byte as it can be and still be precise and accurate. Sacrifice inclusiveness in the hip shot definition sentence only. Then get into it as deeply as necessary to satisfy even the most knowledgeable reader. References are of course essential and do provide some of that depth which will be useful to experts, but imagine if this encyclopedia became so ubiquitous and functional that experts would want to publish here! Wikipedia should be a serious long term source of information as current and technically complete as possible, with an initial hip shot for the superficially interested, many links for the serious lay reader and expert alike, and sufficient depth to attract, satisfy, and retain the expert. The accessibility issue is solved by careful inclusion of copious linking to explanatory concepts. Each reader can link down, or up, to their current level of understanding. (Remember when we had to physically get up and go search down any background we needed, starting in reference books, and proceeding to text after text on the trail and with luck, eventually find even one actual explanation of the concept we were hunting. Links are fun,easy, hierarchical, and inherently self-organizing from the readers point of view, and enable each reader to progress at max speed.) The point being, there is no accessibility issue so long as any user group can quickly link to what they need in order to incrementally build understanding. There is no magic bullet for either the beginner or expert so let's make it deep and complete, and thereby most valuable. 174.30.48.85 (talk) 19:42, 6 November 2013 (UTC)

Many excellent points here. Sławomir Biały (talk) 20:11, 6 November 2013 (UTC)

I disagree here. Articles should be as accessible as possible while being as accurate as possible, not the other way round. There are countless examples of mathematical concepts which have been introduced in a simple setting and then generalized later on. Starting an article with the most general setting prevents many readers from understanding the concept since advanced terminology has to be used. The reader has to look up each unknown term, more new terms pop up, and so on, ending in frustration. Articles should start with the most accessible setting, of course using precise terms and definitions, and then gradually introduce more and more abstraction. Just my opinion, --Quartl (talk) 08:41, 8 November 2013 (UTC)

I think Quartl has a really good point here. Start with the more accessible setting and then move toward higher abstraction and generalizations of the concept. Isheden (talk) 10:09, 8 November 2013 (UTC)

I think the idea of aiming primarily for accuracy and depth is totally and completely wrong for an encyclopaedia. That is writing for the writer not the reader. If they need a more precise idea of the reader they should aim at least the fist couple of sections at I would say someone who is six months away from completing the normal prerequisites for starting on the topic. The sections after can can be more technical. Dmcq (talk) 10:27, 8 November 2013 (UTC)

Some good comments which inspire a bit of clarification regarding my post.

Concerning accessibility vs accuracy. These are not either/or alternatives, but are mutually compatible and can be absolutely concurrent. Consider ... What is the purpose of this encyclopedia, or to rephrase, who is this encyclopedia intended to service, and what do we hope to accomplish on their behalf? I agree strongly with Dmcq here. We are creating this database for the users/readers. So the question is, ... How best to serve them. The purpose is to provide easily accessible, accurate information to anyone who wants it.

A couple thoughts on how we present math. Is math any different than, say, an historical article on the American Civil War. Yes, math is different because of its pre-organized internal logic. Many non-math topics are inherently hierarchical in some senses, such as chronological order of events etc.. But math differs a bit here in that, as a language of logic, it is itself quintessentially hierarchical. This is why I suggest that associated links in math articles are self-organizing. As a lay reader, I can attest that even the most lucid and well written articles still necessitate a constant following of explanatory linking on my part. No problem. If you don't have enough interest to follow links till you get were you need to be, you are never going to really understand the content anyway.

I think part of any apparent disagreement here may be caused by differences in what level of math we are individually imagining presenting in our articles. A lay perspective may be helpful here. Some of you reading this may not remember when any and all math was new to you. But at a certain point, very few readers, including experts, truly "understand" for random example, what "reality" is actually being represented in the most advanced topological correlations of complex math objects with "real world" quantum events, etc.. The point being … as editors and writers, let’s picture such a level for any and all readers, at which we all are just looking for explanatory links and trying to build understanding for ourselves. Picture the following scenario and it may clarify exactly who I think we should be considering with our purpose and depth. Somewhere out there a very gifted kid has just received access to internet service and a computer. He is very interested in math but has no local infrastructure to teach him. He discovers our encyclopedia. I think he should be able to form, from the ground up, with no outside tutoring, a math understanding which places him/her in a position to push the frontiers of math and contribute as an expert. So make it deep for those who can swim there. This does no harm to the superficially interested.

I further agree with both Quartl and Isheden in that it is ideal to start as gently as possible without sacrificing accuracy. For example, if an initial explanatory sentence is in fact technically inaccurate due to say, a lack of inclusion of detail, note this fact and provide a link to further detail. Ideally, all our articles will be well written, non-terminology/jargon laden as possible, and as accessible as possible.

Math has been taught many ways during my lifetime, starting by rote, the "New Math", etc.. But I propose math be taught more like a spoken language, since it is a language. Our children don't need a language hierarchy guide when they learn to speak. People learning math don't either. What they need is freedom and availability of answers to their own individualized questions. Links!

Lastly, my initial post was inspired largely by the thread above regarding editor determined levels of presentation, and was partly intended as a cautionary note. Aside from the unnecessary and extremely difficult and impractical task of reaching mutual agreement concerning what the correct hierarchy of “math level” should be in a given article, there is a more serious concern. We are all prisoners of our own limited world views and understandings. If we “organize” our math content for say, the hypothetical super gifted kid I mention above, who “sees” in math much more clearly than we do, then we are almost certainly doing a large disservice to his understanding by handing him our limited preconceptions of prerequisites and orders of presentation etc.. In math, as with other language acquisition, this imposition of hierarchy is simply unnecessary.174.30.48.85 (talk) 21:04, 8 November 2013 (UTC)

I see practically no point of agreement between what you have said and what I said. You said you strongly agreed with what I said and then went on to say the complete opposite as far as I can make out. Dmcq (talk) 22:25, 8 November 2013 (UTC)

I would like to disagree with the anonymous user's assertion that a bright student should be able to learn mathematics from Wikipedia. Wikipedia is not a textbook. The goal of an encyclopedia – any encyclopedia, including Wikipedia – is to provide an overview of a topic. An encyclopedia article may have more or less depth, but it should never be more than an overview. This is why Wikipedia math articles generally do not contain proofs. While proofs are sometimes appropriate, just as proofs are sometimes appropriate in published survey articles, most of the time proofs should be confined to text books and research papers. For this reason, a serious and conscientious student will never be able to learn a subject from Wikipedia. They will need to look up the details in a comprehensive source, and this is no different in mathematics than in any other subject. Ozob (talk) 04:23, 9 November 2013 (UTC)

Thinking of articles as surveys sounds good to me. Dmcq (talk) 13:00, 9 November 2013 (UTC)

It appears the main issue in this thread is really … What is the purpose and intent of an encyclopedia? I propose we seriously rethink this question. I agree that in the past, when limited to a number of hard copy volumes which could reasonably fit in a person’s home, an encyclopedia was intended for general overview. It was also specifically for the lay public and did not generally contain articles written by, or intended for experts, or any great technological depth. That purpose was the result of a perceived marketing niche, combined with a practical physical limitation. Names like “The Book of Knowledge” hint at greater aspirations, but these aspirations were just impractical to the point of impossibility. Let’s not make the common mistake of underestimating the current information revolution, or limit our own resource goals because we don’t understand our future potential. We don’t know the future of this Wiki resource in great detail, but we can speculate a bit. We now have a magic book of knowledge in one beautifully bound volume. You probably have it in your lap right now. It can do anything the old encyclopedia on your hall shelf could do, and so much more. We are at the dawn of this information/connectivity era and we can format this resource any way we want. First though, let’s consider our resources for building Wikipedia. Despite constant criticism, I don’t share any real pessimism whatever regarding the eventual power, accuracy, or integrity of a Wiki site. Our engine is the strongest. It is humanity itself, tireless. Our engine will work 24 hours a day until those of us reading this thread now are dead and gone, and then our engine will work on. We need to rethink this resource’s ultimate purpose because the eventual capacity and the real power and longevity of the Wiki engine is beyond our current imagination. Our magic one volume encyclopedia has no last page! This does not mean it is an annoyingly long book which you just can’t seem to finish. It can be written so it is comfortable to stop at any time, or you can go on, or you can skip ahead as far as you want. We know more today than we did 10 years ago about how self-organizing and resistant to intended boundaries internet sites are, which is all Wikipedia is after all. Our ultimate layout is a fractal hierarchy with indefinite resolution, whether we intend this today or not. To respond specifically to some of the posts above, visualizing a fractal net structure. We can make the largest scale appear and function much like an old style encyclopedia. This satisfies those of us who think of and intend to use this tool as a source of general overview. No problem. A bit deeper it functions and feels more like a text book. Math proofs for example would belong here. Maybe not today, but time and essentially unlimited input resources could make Wikipedia as deep and connected as the future of the resource can make it, and that is very deep. This is why I say we can serve many purposes at once with this tool, and hurt or limit no user group with our depth and connectivity. It is important to have this dialogue because we are suggesting a future evolutionary course and scope for Wikipedia. How well we model the future, in terms of structure and what people will come to want and expect, greatly affects ultimate success of this tool.

A couple more stray thoughts. At some point we may link to each and every element in the library of congress or the future equivalent, patent data base, medical data base, … (n) data base. At some point all users may be linked to each other if they so choose. Experts will be publishing and roaming in the deeper fractal layers of this net which will not be exclusively linked to Wikipedia of course, but associated with this Wiki tool only to the extent that we make it so. At some point Wikipedia may just be a name on a particular internet portal. A data base in the future will not have any of our currently expected limits. A lesson we learn from Google is that the model behind the engine is very important.

I understand the importance of limits. Do what you do and do it well, don’t try to do everything. This is still true and for current practical purposes, some of the posts above regarding limitation of this resource are very valid. I only say, let’s make our model forward compatible.174.30.50.14 (talk) 21:02, 9 November 2013 (UTC)

Elementary Mathematics on Wikipedia

There is an article Elementary Mathematics on Wikipedia by Adrian Riskin of Whittier College on Wikipediocracy which expresses similar concerns an looks at the polynomial article in particular. It might be worth a read.--User:Salix alba (talk): 21:07, 8 November 2013 (UTC)

Yes that article describes the problem okay, we need to have a decent idea of who we're writing for and then write for them. We're trying to construct a knowledge utility not a perfect gleaming spire. As opposed to that article though I believe as an encyclopaedia we should be writing on topics rather than being a dictionary with short simple definitions. Dmcq (talk) 22:25, 8 November 2013 (UTC)

That article came up in the Polynomial talk page previously when someone tried to address the criticisms. The polynomial article was being used as an example of supposedly systemic problems with WP as a whole, so fixing a single article is not the point. Not that WP doesn't have some issues, but I don't see how sniping on a different site is supposed to be helpful. If you find the articles poorly written or unhelpful then you're free to use another source of information. If someone has constructive criticism to offer then I'm sure most of us will try to take it on board, but I think we can ignore people who basically say "I picked this article at random and it sucks." --RDBury (talk) 15:12, 9 November 2013 (UTC)

Beta Features

Just FYI about an upcoming software change related to mathematics: The new "Beta Features" program is being introduced for opt-in-only for testing of new and experimental software features. One of the features in the initial testing set (available here on approximately 21 November) will be the LaTeX-based math formula editor for VisualEditor. There is some more information at https://blog.wikimedia.org/2013/11/07/introducing-beta-features/ and mw:About Beta Features for anyone who is interested. Whatamidoing (WMF) (talk) 19:53, 9 November 2013 (UTC)

Good news. Thanks for starting the implementation of the VE math editing features earlier rather than later. I look forward to trying it. --Mark viking (talk) 21:35, 9 November 2013 (UTC)

Wikipedia talk:Articles for creation/Transformation on the graph from a basic function using Log and LN

Dear mathematicians: Is there anything worth saving in this old AfC draft? —Anne Delong (talk) 16:22, 9 November 2013 (UTC)

Well, no. This is mostly a how to guide for a particular topic in something like high school analytic geometry. --Mark viking (talk) 17:09, 9 November 2013 (UTC)

No. It's like a poorly-written study guide. Ozob (talk) 17:10, 9 November 2013 (UTC)

Fine. I have tagged it for deletion. —Anne Delong (talk) 22:12, 9 November 2013 (UTC)

Wikipedia talk:Articles for creation/Brilliant number

Dear mathematicians: I first read about this mathematical term in a P.D. James novel. Is it notable enough to have an article? —Anne Delong (talk) 20:40, 11 November 2013 (UTC)

Wikipedia talk:Articles for creation/Atto-fox problem

Dear mathematicians: Another old stale Afc submission. Should it be saved or let go? —Anne Delong (talk) 14:56, 11 November 2013 (UTC)

I think the material there is valuable, and in its present form the best thing to do with it would be to merge it with Lotka–Volterra equation to create a new section, expanding on the more limited material in Lotka–Volterra equation#An_example_problem. Maybe the simplest thing to do would just be to copy it onto the talk page for Lotka–Volterra equation and let someone do the merging. --JBL (talk) 20:42, 11 November 2013 (UTC)

Thanks. I have left a note on the Lotka–Volterra equation talk page and postponed G13 deletion of the article for six months to give time for this to happen. —Anne Delong (talk) 23:20, 11 November 2013 (UTC)

input requested

To this discussion here: Wikipedia:Categories_for_discussion/Log/2013_November_12#Category:Gabriel.27s_variety. My question for this board is, are objects which have infinite surface area but finite volume (or, for example, infinite perimeter and finite area) discussed as a group? The current category name is clearly wrong, but I'm curious whether this grouping of objects by those characteristics is discussed in the literature, and if you can think of other examples of such objects. Input is welcome at the linked discussion board.--Obi-Wan Kenobi (talk) 21:44, 14 November 2013 (UTC)

Linear_space_(geometry)

I think Linear_space_(geometry) is a duplicate of incidence geometry. Does it look that way to everyone else too? I imagine the original author might have been translating from German and might have overlooked the other page. Although a lot of the content is the same, I'm putting up a merge tag to encourage people to move useful stuff from this article into the incidence geometry article. Rschwieb (talk) 00:21, 14 November 2013 (UTC)

Although I am not supporting User:Kmhkmh's quick removal of the merge tag, I am slightly inclined to keeping the articles separate. The vast majority of incidence geometries are not linear spaces, or even partial linear spaces. Unfortunately, those that aren't at least partial linear spaces are not very interesting from a geometrical point of view (although they may have a wider appeal if viewed as hypergraphs). To keep the articles separate, the incidence geometry article would have to be loaded up with what I consider to be uninteresting examples. While this may be the "right thing to do", I don't feel very good about it. Bill Cherowitzo (talk) 16:52, 14 November 2013 (UTC)

I didn't mean to block a discussion, I just removed the tag because it made little sense to me and when I came across it there was no related thread on the linked discussion page either, hence removed it.

Why does merging make little sense to me? Because a linear space is to incidence geometry roughly what a group (or any other particular algebraic structure) is to algebra. Meaning you usually want/need separate articles for both. One being a larger overview/survey article and the other being more specialized. In theory one could argue as long as there isn't tat much material covered in total one article, that is the overview article, might suffice temporarily. The emphasis however is on temporarily and in this case we already have 2 articles. So what's the point in merging them now just to split them off again sometime later?

Having said that it might make sense to reduce the current redundancy somewhat, that means the Erdös-de Bruijn theorem and detailed definition of linear spaces could be shortened in incidence geometry and moved over to linear spaces. But more importantly the incidence geometry needs to be turned into real overview article on incidence geometry rather than being only a (detailed) introduction into linear spaces for the most part. The literature under references actually covers all that, but its content hasn't really been used for the article yet. In that sense the incidence geometry is missing its topic a bit currently, but that problem doesn't really get fixed by merging the articles (unless we merge it under the same linear space and sort of "dump" incidence geometry for now).

All in all we have 2 articles existing in their own right and which both need to extended/rewritten separately in their own way. Once that happens the relative high degree of redundancy, they currently have, will fade away anyhow.--Kmhkmh (talk) 00:08, 15 November 2013 (UTC)

Subsequently, a few things Kmhkmh mentioned dispelled my doubts, so please consider this idea retracted. The task has turned more into "make sure these articles work with each other with a minimum of redundancy." Rschwieb (talk) 14:19, 15 November 2013 (UTC)

DrMicro

Project members may wish to see Wikipedia:Contributor copyright investigations/DrMicro — apparently DrMicro copied or too-closely paraphrased some of his sources over a long series of edits, some of which involve mathematics or statistics. I checked three of the mathematics articles and found a problem in one of them, unimodality, but there's a lot more to check. —David Eppstein (talk) 05:41, 16 November 2013 (UTC)

Wikipedia talk:Articles for creation/Summation formulae

Another editor created Wikipedia talk:Articles for creation/Summation formulae. The submission lacks references, and I cannot tell whether the topic is notable. The assistance of other editors would be appreciated. Eastmain (talk • contribs) 23:22, 16 November 2013 (UTC)

The only source is a website that discusses the formulation in more detail. From what I can tell, this is a technique for an analog of integration (Indefinite sum) in the finite difference calculus based on the Euler summation formula. The website has no references of its own, so I am formed to conclude that this is a bit of original research. As far as I can tell, not suitable for mainspace. --Mark viking (talk) 00:18, 17 November 2013 (UTC)

Agree -- looks like someone's personal research notes or something. I don't think it has any plausible path to becoming an article. --JBL (talk) 01:12, 17 November 2013 (UTC)

Paul Conrad

An editor, while creating an article about an (apparently) more notable Paul Conrad, found references to a mathematician listed in the American Men & Women of Science. He lived from 1921-2006 and worked at the University of Kansas on ordered algebraic systems and group theory. I haven't worked in those fields, and have had difficulty finding information on him, other than a large number of "descendants" at the Mathematics Genealogy Project. Anyone want to work on that? — Arthur Rubin (talk) 19:28, 17 November 2013 (UTC)

AfC submission

Care taking a look at Wikipedia talk:Articles for creation/Remez polynomial? Thanks! FoCuSandLeArN (talk) 16:49, 18 November 2013 (UTC)

Negative hypergeometric distribution

This article is completely wrong. It seems to be a copy of Hypergeometric distribution. Sincerely, --Quartl (talk) 08:35, 18 November 2013 (UTC)

Encyclopedia of Mathematics seems to confirm that the negative hypergeometric distribution is the same as the hypergeometric distribution with different parameters. I don't remember that as being accurate, but I can't find a source to the contrary, at the moment. — Arthur Rubin (talk) 14:04, 18 November 2013 (UTC)

With different parameters? Not quite so. "The distribution function $F(n)$ of the negative hypergeometric function with parameters $N,M,m$ is related to the hypergeometric distribution $G(m)$ with parameters $N,M,n$ by the relation $F(n)=1-G(m-1).$" Note n is an argument for the former but a parameter for the latter. True, "This means that in solving problems in mathematical statistics related to negative hypergeometric distributions, tables of hypergeometric distributions can be used." However, these are really different distributions. Just like the functions $x\mapsto a^{x}$ and $x\mapsto x^{a}$ are really different functions. Boris Tsirelson (talk) 15:04, 18 November 2013 (UTC)

Sorry. Perhaps whoever created the article read it that way, though.... — Arthur Rubin (talk) 18:26, 18 November 2013 (UTC)

Indeed! Boris Tsirelson (talk) 20:04, 18 November 2013 (UTC)

The negative hypergeometric distribution is related to the hypergeometric distribution just as the negative binomial distribution is related to the binomial distribution. Both describe similar events, but are different distributions. The probability mass function of the negative hypergeometric distribution should be

$P(X=n)={\frac {{\binom {n-1}{k-1}}{\binom {N-n}{K-k}}}{\binom {N}{K}}}$

while the probability mass function of the hypergeometric distribution is

$P(X=k)={\frac {{\binom {n}{k}}{\binom {N-n}{K-k}}}{\binom {N}{K}}}$

(parameters as in hypergeometric distribution). The formula in the EoM article seems to have an extra parameter $n$ whose role is unclear to me since it is not explained in the text. Best wishes, --Quartl (talk) 20:21, 18 November 2013 (UTC)

Agreed. This article has a clear exposition of the relations of these different distributions and could be used as a source in the article. The associated R module refers to Wilks, S. S. (1963), Mathematical Statistics, Wiley. --Mark viking (talk) 20:44, 18 November 2013 (UTC)

Math 2.0

Just in case someone here is interested and/or can help, see:

• [Wikitech-l] Math 2.0 (feedback wanted)

Helder 11:41, 20 November 2013 (UTC)

Perfect set versus perfect sets

Perfect set redirects to Perfect space, while Perfect sets redirects to Derived set (mathematics). Rather strange. Boris Tsirelson (talk) 08:34, 20 November 2013 (UTC)

The first redirect should go in the other direction. Perfect sets (contained in some larger topological space) are the more important notion; just because the concept can be defined intrinsically doesn't mean it should be. --Trovatore (talk) 08:39, 20 November 2013 (UTC)

I see. And what about "Perfect sets"? Why such entry? Boris Tsirelson (talk) 11:19, 20 November 2013 (UTC)

That should also redirect to perfect set, of course. --Trovatore (talk) 17:31, 20 November 2013 (UTC)

Article needs a slight fix..

For the "Siegel–Walfisz theorem" - the first line in the statement section defines the equation and then points out the symbols are the von mangoldt function and the totient function... I'm not sure if that line was meant to be at the bottom of that section or if the defintion is incorrect, but the totient function doesn't appear in the definition directly preceding..

It was a little confusing - maybe someone can clarify it? Thanks.. — Preceding unsigned comment added by 96.57.251.228 (talk) 16:52, 14 November 2013 (UTC)

In the original language they were separate sentences. Should be clear now. ᛭ LokiClock (talk) 19:59, 21 November 2013 (UTC)

Equilateral and Isosceles

I see that about a week ago, User:Duoduoduo changed both of these into disambiguation pages, with a lot of incoming links. This seems wrong - before disambiguators start fiddling with all of these the articles, is there no primary meaning of these terms in mathematics? bd2412 T 22:15, 20 November 2013 (UTC)

In both cases I think the triangle meaning is the WP:PRIMARYTOPIC. Certainly the other meanings exist, but are much less common. And "Venus Equilateral" should not even be on the dab page — dabs aren't supposed to list everything that has a substring matching the title, but only subjects that could reasonably be referred to by the whole title. —David Eppstein (talk) 22:45, 20 November 2013 (UTC)

Same for "Isosceles triangle theorem." ᛭ LokiClock (talk) 19:51, 21 November 2013 (UTC)

I suspected as much. I am going to move these to "Foo (disambiguation)" titles and restore the original redirects. Thanks! bd2412 T 19:55, 21 November 2013 (UTC)

 Done. Cheers! bd2412 T 19:59, 21 November 2013 (UTC)

AfC submission (2)

Wikipedia talk:Articles for creation/Minimum maximal k-partial-matching problem. FoCuSandLeArN (talk) 22:17, 21 November 2013 (UTC)

Gromov boundary

I've created the article Gromov boundary, but I could use help putting in the (very complicated) definitions, as my wiki-latex is not as good as it could be. Thanks!Brirush (talk) 17:20, 22 November 2013 (UTC)

Requested move of perfect space

Thanks to Boris Tsirelson for bringing this to my attention above. I have proposed that perfect space be rewritten slightly and moved to perfect set over the redirect. Please comment at talk:perfect space#Move and rewrite slightly. --Trovatore (talk) 19:46, 22 November 2013 (UTC)

No cyclic numbers in square bases...

The article on Cyclic numbers has the following sentence in it:

It can be shown that no cyclic numbers (other than trivial single digits) exist in any numeric base which is a perfect square; thus there are no cyclic numbers in hexadecimal, base 4, or nonary.

. It seems a little odd to phrase this in this way and if the proof is easy, it might be more correct to include it instead of "It can be shown".Naraht (talk) 12:40, 25 November 2013 (UTC)

This was discussed recently at the Mathematics Ref Desk here. Gandalf61 (talk) 12:51, 25 November 2013 (UTC)

Semi-cyclic numbers

Any difference between cyclic and semi-cyclic numbers that makes it so that cyclic numbers are interesting but semi-cyclic numbers are not?? (For clarification on what I mean, go to the Details section of the Cyclic number article and there's an example. Georgia guy (talk) 16:02, 25 November 2013 (UTC)

Spread polynomials

Wikipedia:Articles for deletion/Spread polynomials may be of interest to this community. -- 101.119.26.132 (talk) 06:14, 27 November 2013 (UTC)

Correction for a possible error in the "Hexomino" article

Under the heading "symmetry", the fifth bullet point down says: "2 hexominoes (coloured purple) have two axes of mirror symmetry, both aligned with the grid lines. Their symmetry group has four elements. It is the dihedral group of order 2, also known as the Klein four-group."

What I see is that hexominoes 1 and 22 have this type of symmetry. However, their symmetry is partly aligned with the grid lines and partly not aligned. Hexomino 1 has a horizontal axis of symmetry which divides it evenly in in half around it's middle along the grid lines, but the vertical axis of symmetry is not along the grid lines. And Hexomino 22 has vertical symmetry along the grid lines, but horizontally it divides itself along it's middle tiles and not along the grid lines.

--Matt.mawson (talk) 16:21, 27 November 2013 (UTC)

I think "aligned with" means "parallel to" here. So the description is simply saying that one axis of mirror symmetry is horizontal and the other is vertical - they do not necessarily have to be along the grid lines themselves. I have clarified this description at hexomino. Gandalf61 (talk) 16:30, 27 November 2013 (UTC)

Free abelian group

See the recent edits to free abelian group and the discussion at Talk:Free abelian group#Subgroup Closure. More opinions would be helpful here. —David Eppstein (talk) 15:25, 28 November 2013 (UTC)

New WikiProject? WP:WikiProject Mathematicians

Alternatively WP:WikiProject Mathematicians and Scientists / WP:WikiProject Scientists and Mathematicians.

I will explore this and other WikiProjects further to see if this need has been addressed elsewhere.

24.97.221.98 (talk) 18:09, 27 November 2013 (UTC)

There is WikiProject Biography/Science and academia. It doesn't seem very active despite the nearly 50,000 articles it covers. RockMagnetist (talk) 18:17, 27 November 2013 (UTC)

Also relevant are Wikipedia talk:Notability (academics) (reasonably active) and Wikipedia:WikiProject Deletion sorting/Academics and educators (very active and regularly updated). —David Eppstein (talk) 19:09, 27 November 2013 (UTC)

Yet another is Wikipedia:WikiProject Physics/Taskforces/BPH. RockMagnetist (talk) 02:24, 30 November 2013 (UTC)

Bhaskara's 12th century calculus

Recently the following text was added to calculus: In 12th century, Bhāskara's gave the principles of differential calculus and its application to astronomical problems and computations. He was perhaps the first to conceive the differential coefficient and differential calculus. This is reported in the name of Goonatilake 1999. I wonder how much historical detail the page calculus (as opposed to history of calculus) should contain, and how such details should be evaluated for reliability. Tkuvho (talk) 16:00, 26 November 2013 (UTC)

Several peer-reviewed articles in reputable journals would be a good start. Inventing calculus is a tall claim; there'd better be damn good evidence for it. User:Linas (talk) 21:28, 30 November 2013 (UTC)