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Revision as of 13:14, 6 May 2013 editIncnis Mrsi (talk | contribs)Extended confirmed users, Pending changes reviewers, Rollbackers11,646 edits →Hurwitz Campaign: an unexpected continuation: new section← Previous edit Revision as of 13:28, 6 May 2013 edit undoMathsci (talk | contribs)Autopatrolled, Extended confirmed users, Pending changes reviewers66,107 edits →Hurwitz Campaign: an unexpected continuationNext edit →
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There is an article ] in the Afc just now that could use some attention from someone with mathematical knowledge. —] (]) 01:40, 5 May 2013 (UTC) There is an article ] in the Afc just now that could use some attention from someone with mathematical knowledge. —] (]) 01:40, 5 May 2013 (UTC)


== Icnis Msri cannot follow an argument ==
== Hurwitz Campaign: an unexpected continuation ==


An amazing argument over the so named '']'': see ]. Ironically, the editor who recently removed my ambox is himself found to distort the notation of Faraut & Koranyi beyond recognition. ] (]) 13:14, 6 May 2013 (UTC) An amazing argument over the so named '']'': see ]. Ironically, the editor who recently removed my ambox is himself found to distort the notation of Faraut & Koranyi beyond recognition. ] (]) 13:14, 6 May 2013 (UTC)
:Why post this nonsense when (a) you just made a stupid undergraduate/highschool mistake (poor guesswork) (b) you didn't lift a finger to check the source (b) you did not read what the article said (d) you did not look at my reply. Since you cannot be bothered to read my replies here is the explanation. The inner product on quaternions is Re ''ab''*= Re ''b''*''a''. So
(''L''(''a'')''b'',''c'') = Re ''c''*''ab''= Re (''a''*''c'')*''b'' = (''b'',''L''(''a''*)''c''). So ''L''(''a'')* = ''L''(''a'')* by the definition of adjoint on a finite dimensional real inner product space. Why are wasting time like this and making such silly errors? ] (]) 13:28, 6 May 2013 (UTC)

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Space Wars

Poincaré group

Sadly, editing patterns usual for nationalistic (and other) PoV pushers apparently are acceptable even in purely scientific articles. This editor not only summarily undid the edit I made for no less than 30 minutes, not only did not he put any notice to the talk: Poincaré group, but his edit summary did not point to any concrete problem with an edit consisting of a lot of changes. Incnis Mrsi (talk) 04:34, 15 April 2013 (UTC)

Y'all seem to be working it out just fine. You can also start the talk section by responding to the revert's comments. ᛭ LokiClock (talk) 01:53, 16 April 2013 (UTC)

To where do shapes from Euclidean geometry belong?

The article Euclidean geometry should explain the history and traditional methods. But where should actual things from Euclidean spaces be listed: in Euclidean space #Geometric shapes? Or there are better suggestions?

BTW, there is a list of geometric shapes which, as can be seen in its preamble, is devoted to plane shapes only. I feel that the adjective “geometric” is a misnomer in such case. Incnis Mrsi (talk) 17:54, 18 April 2013 (UTC)

Compounding the problem, there is a List of mathematical shapes which would be better named List of geometric shapes. Perhaps it should be renamed, and the current List of geometric shapes moved to List of planar geometric shapes. RockMagnetist (talk) 17:31, 19 April 2013 (UTC)
BTW neither henagon nor digon are actually “planar”. IMHO list of two-dimensional geometric shapes would be better. I go to create “list of shapes” as a list of list, for both mathematical lists and not so. Incnis Mrsi (talk) 18:20, 19 April 2013 (UTC)

Is Euclidean space relevant to the definition of a manifold?

Two editors object against replacement of “Euclidean space” with “coordinate space” and “real coordinate space” in the Manifold article on pretexts that complex and p-adic manifolds are unheard of, that Euclidean space is a more familiar concept, etc. I do not think that pushing the “Euclidean space” link wherever a reader is expected to be more familiar with this concept is a good practice. See talk: Manifold #"Euclidean space" or "coordinate space"?. Incnis Mrsi (talk) 16:16, 19 April 2013 (UTC)

“Vector” redirects

I retargeted 10 redirects previously bound to Euclidean vector to other targets. Maybe, hatnotes or some content should be added? Or some of misleading redirects were missed? Incnis Mrsi (talk) 15:15, 21 April 2013 (UTC)

I redirected Vector component back to Euclidean vector#Decomposition (a different section than previously). A reader who needs information on what a vector component is probably needs a less abstract and more directly applicable treatment than is found in Basis (linear algebra). I will fix Vector components and Component (vector) to point to the same place for consistency. I added a "more info" link pointing to Basis (linear algebra).--Srleffler (talk) 01:07, 23 April 2013 (UTC)
Going over the rest of your list:
These changes are typical of a problem I have seen with mathematics articles on Misplaced Pages: too damn much of the material is written by and for mathematicians, so that concepts that can be explained simply and directly are instead explained with great generality and abstraction, using concepts and methods that are beyond the level of some readers who might be interested in the topic, and who would have the background to understand it if it were approached differently. The most rigorous explanation is not always the best one pedagogically. Vector components, addition and subtraction are suitable topics for a high school senior, and the directly-linked articles should be at that level, with links to more advanced treatments available from the simpler articles.
I haven't changed any of the other links yet, so we can talk this through first.--Srleffler (talk) 01:32, 23 April 2013 (UTC)
These changes are typical of a problem I have seen with scientific articles on Misplaced Pages: too damn much accommodation to “what a reader wants to see”, at the expense of precision. It is not especially important for Vector addition/Vector sum and Vector subtraction, but it is quite important for “components”, because these redirects suggest that these are namely Euclidean vectors which have components, not any others. I would prefer to see Physical vector and Vector (physics) as red links (if only because 4-vectors exist), although we should consult WP:WikiProject Physics about this two targets. Incnis Mrsi (talk) 05:48, 23 April 2013 (UTC)
I've reverted pending consensus. Vector component is definitely not better explained by Euclidean vector#Decomposition than by Basis (linear algebra). When a reader is required to know the technical details of how decompositions are performed before the formalism of an article becomes accessible, the linking of the article is often the only clue of where to go to decipher things. A simplification is also not appropriate as a redirect, because redirecting implies the article that would be about that subject is under another title, and Euclidean vector#Decomposition is not the article about vector components. ᛭ LokiClock (talk) 09:48, 23 April 2013 (UTC)
Take another look at the two articles. A reader who is encountering vector components for the first time in high school or first year university is going to find the introduction to Basis (linear algebra) completely impenetrable. In an encyclopedia it is important to treat each topic at the simplest level possible (which varies from topic to topic), before moving into more complicated or abstract aspects of the topic. --Srleffler (talk) 02:23, 24 April 2013 (UTC)
It's not important to treat things at the simplest level possible, it's important to treat them comprehensively. Encyclopedias are not textbooks. Basis (linear algebra) may be impenetrable, but some things are impenetrable because they're new concepts that you have to take the time to wrap your head around. Having learned from it at high school age, I would say it's semipermeable. Now that it has that nice picture, it's a lot less work. Now, I would be mentally impoverished if all the Misplaced Pages articles I read during that time were subject to every editor's idea of the best way to dumb it down, what I don't need to know, and what my purposes for the information should be. I actually didn't need to understand Euclidean vector components and vector decompositions the most, I needed to know what a basis is and linear combination are. ᛭ LokiClock (talk) 14:21, 25 April 2013 (UTC)
Simplicity and comprehensiveness are not mutually exclusive. We just need to arrange material and links so that a reader is more likely to find simpler material first, if that is appropriate based on the link they clicked. It doesn't make sense to throw a reader looking for information on vector components to an article on a much more general concept, where the first paragraph of the introduction assumes knowledge of half a dozen concepts that may not be familiar. A high school student who has encountered vectors in physics and math class would be immediately put off by Basis (linear algebra). To even get past the first paragraph, you have to understand the concepts of linear independence, linear combination, vector spaces, free modules, and spanning sets. None of these concepts are likely to be familiar. Redirecting vector component to this article is totally crazy.--Srleffler (talk) 22:09, 27 April 2013 (UTC)
I changed vector addition and subtraction to simply redirect to vector space because the operations are conceptually motivated throughout, as a function of vector spaces being algebras. I left vector sum because it might get confused with elements of the direct sum. ᛭ LokiClock (talk) 09:55, 23 April 2013 (UTC)
It should not be necessary to explain vector spaces in order to explain the concept of vector addition and subtraction. This is a bad redirect.--Srleffler (talk) 02:23, 24 April 2013 (UTC)
What? That's all a vector space is, its addition and scalar multiplication. All those figures in vector space are dedicated to explaining what vector addition and scalar multiplication mean intuitively. ᛭ LokiClock (talk) 14:10, 25 April 2013 (UTC)
You're missing the point. Vector space is a more abstract concept than vector addition and multiplication. Start with the simple; move to the abstract later. You probably didn't learn about vector spaces before you learned how to add and subtract vectors. Why would you expect a reader looking for information on vector addition to have to master this much more difficult subject first?--Srleffler (talk) 22:09, 27 April 2013 (UTC)

I support all of the original changes. I'm not sure vector component, component (vector), etc. (in the singular) have a perfect redirect target. Does this mean a component of a vector in a basis, or is it the scalar projection of a vector in some direction (as the term "component" is sometimes used)? Sławomir Biały (talk) 11:33, 23 April 2013 (UTC)

I don't at present have a position on the current status of things but I would like to register a preference that all links under discussion are chosen in opposition to the principle "too damn much accommodation to “what a reader wants to see”, at the expense of precision."" -- most of these links should go to the most elementary, and emphatically not the most general, treatment of the subject in question. If we're not presenting material a reader at the appropriate level (say, a bright high school student) can understand then we're doing things wrong. --JBL (talk) 14:05, 23 April 2013 (UTC)
I would oppose redirecting Vector component to Basis (linear algebra).. I would prefer a redirect to somewhere within Euclidean vector (per JBL). There is also the article Vector projection (to which Scalar projection should probably redirect). Mark M (talk) 14:33, 23 April 2013 (UTC)
“Vector projection” presently has a strong Euclidean bias. If one can reformulate the definition in purely affine terms, specifying that orthogonal projections are a particular case, then it would be a solution. Incnis Mrsi (talk) 07:03, 24 April 2013 (UTC)
I don't see why it should be done in terms of affine geometry. Is there evidence that this notion of vector projection is more common? Sławomir Biały (talk) 11:10, 24 April 2013 (UTC)
It should be done in terms of affine geometry because any orthogonal projection is an affine projection, but any skew (affine) projection is not an orthogonal projection; I believe you knew it yourself. Why should I find evidences that the affine projection “is more common”? Or let us rewrite the percentage article in terms of money on the pretext that this notion of percentage is the most common. Incnis Mrsi (talk) 10:16, 26 April 2013 (UTC)
I'm unaware of any mandate that articles should immediately take the most general perspective possible. A more general notion of projection is already covered at Projection (linear algebra). The article under discussion is about the vector projection in elementary Euclidean geometry. Why is it that you think that readers will expect an article about affine geometry when they type "vector projection" into the search bar? Of the 5000 available on Google books using the term "vector projection", only 36 also include the word "affine". And even in most of those few references, the vector projection is regarded as an Euclidean concept. Sławomir Biały (talk) 11:20, 26 April 2013 (UTC)
It just means that “projection (linear algebra)” is a possible target for redirecting “component (vector)”, but (the present) “vector projection” is not. Bases do exist in spaces which provide no orthogonality. Incnis Mrsi (talk) 11:29, 26 April 2013 (UTC)
I think there's something you're still not understanding. We're meant to be a general encyclopedia, and need to accommodate a wide array of readers, many of whom lack mathematical sophistication but for whom an article on Euclidean vector projection is useful. It is extremely uncommon in the literature to use the exact term "vector projection" to refer to anything but the standard Euclidean notion. I'm not arguing that there aren't more general concepts of projection available; for that there are other articles: projection (linear algebra), projection (mathematics). What I'm asking is, what is the evidence that the exact phrase "vector projection" is used to refer to one of these more general notions? If it is not used in this manner, then clearly we should not take the more general perspective. If there are sources that do use it in ----- WP:WEIGHT to attach to those sources. Sławomir Biały (talk) 11:37, 26 April 2013 (UTC)
Another fine example of the problem of too much focus on the needs of mathematicians. It should not be necessary for a reader to figure out what affine geometry is to get some information on vector components. Vector components is a high-school level topic. Affine geometry is not. --Srleffler (talk) 22:09, 27 April 2013 (UTC)
I am with Srleffler and JBL. Those redirects should go to the elementary articles.
As for Srleffler's remark that "...too damn much of the material is written by and for mathematicians...", Euclidean vector certainly is not written for mathematicians, neither is vector space for that matter. We just need to figure out how to redirect appropriate audiences to appropriate articles. Mct mht (talk) 10:53, 24 April 2013 (UTC)

Please, contribute to this discussion. In short: a WP:CONCEPTDAB article about vectors could become a long-term compromise. Incnis Mrsi (talk) 11:42, 24 April 2013 (UTC)

Describing vectors simply?

Not related to DABs and all, but there were comments above about basis (linear algebra)/vector space as "impenetrable" or overly abstract... To this end I quickly cobbled two diagrams as you can see on talk:basis (linear algebra)#Diagrams and talk:vector space#Diagrams, if case they're any diagrammatic help... Regards, M∧ŜcħεИτlk 17:26, 25 April 2013 (UTC)

I think change of basis needs that illustration. ᛭ LokiClock (talk) 12:02, 26 April 2013 (UTC)
I'll take the liberty of adding them (after slight modifications) to that article. Thank you for pointing this out. M∧ŜcħεИτlk 22:55, 26 April 2013 (UTC)

Euclidean space, Euclidean vector, and inner product space

There is some overlap between these topics. For example, all three should consider the concept of angle. To which extent should first two articles rely on each other? To which extent should both rely on “inner product space”? This is also related to the question immediately above. Incnis Mrsi (talk) 07:49, 25 April 2013 (UTC)

BTW, I just discovered Euclidean subspace, yet another article full of abominations: see talk: Euclidean subspace. Incnis Mrsi (talk) 06:50, 27 April 2013 (UTC)

Proposal to delete our article on an axiom of set theory

Please see Misplaced Pages:Articles for deletion/Axiom of global choice. Eozhik (talk · contribs) believes that Axiom of global choice is a hoax. Obviously, I disagree. If you have an opinion on this, I urge you to express it on the AfD page. JRSpriggs (talk) 09:28, 21 April 2013 (UTC)

The nomination for deletion was withdrawn after considerable discussion. JRSpriggs (talk) 21:38, 22 April 2013 (UTC)

Marilyn's Cross marked with Template:Hoax

An editor has listed Marilyn's Cross in Category:Misplaced Pages suspected hoax articles. Since this appears to be the relevant WikiProject, someone in this project might want to participate in the discussion (if you have not already done so). Hyacinth (talk) 21:16, 22 April 2013 (UTC)

See the discussion two sections above about this article. It is not clear that it is formally a hoax, but it appears that the author may have given her own name to a common knot and then wrote an article about it. If so, then it would qualify as original research, probably non-notable, and possibly redundant. I am not knowledgeable enough about knot theory to make a definitive call on OR and redundancy, but there doesn't seem to be much in the way of independent reliable sources for this article. --Mark viking (talk) 21:53, 22 April 2013 (UTC)
Now renamed to L10a140 link, and the "Marilyn" part greatly de-emphasized. AnonMoos (talk) 13:59, 4 May 2013 (UTC)

Domain (mathematics): fixes to ∼ 150 inbound links? Or back to domain of a function with a hatnote?

I do not know what to do with these consequences of those clumsy changes in 2009 (and earlier). And the proposal about deprecation of redirects, which could avoid this kind of situation in the future, also did not attract any support. Incnis Mrsi (talk) 09:26, 23 April 2013 (UTC)

IMO, the easiest solution is to redirect Domain (mathematics) to Domain of a function, and to add to the latter a hat note For other use of "domain" in mathematics, see Domain#Mathematics D.Lazard (talk) 10:03, 23 April 2013 (UTC)

Kerala fundamental contributions to calculus

It would be interesting to determine whether http://en.wikipedia.org/search/?title=History_of_calculus&diff=551937571&oldid=546717260 is a helpful edit. Tkuvho (talk) 12:26, 24 April 2013 (UTC)

I'd not give much weight to the source cited there. I have nothing in principle against including mention of the Kerala school there, but adequate sources are needed to give a sense of historical perspective. It's never been clear from more mainstream sources what weight should be assigned to the Indian mathematicians. It doesn't bode well that the source in question claims "imperialist suppression". True or not, this is a classic red flag of fringe science. Sławomir Biały (talk) 14:49, 24 April 2013 (UTC)

"Namesakes"

This edit was done by a user whose most recent edit history does not mention the following:

Michael Hardy (talk) 02:46, 26 April 2013 (UTC)

The new version is neither clearer nor less vague, and also reads awkwardly. I recommend reversion. --JBL (talk) 03:07, 26 April 2013 (UTC)
I've complained there that it is much more vague, to many people namesake means anything or anyone with a name like Leonhard Euler, and not necessarily named after the mathematician. Dmcq (talk) 03:28, 26 April 2013 (UTC)

I've changed the article's title back to List of things named after Leonhard Euler and commented on the article's talk page about my reasons for this. Michael Hardy (talk) 13:49, 26 April 2013 (UTC)

Good job. -AndrewDressel (talk) 21:53, 26 April 2013 (UTC)

Organization of the List of things named after Archimedes

I've just organized the List of things named after Archimedes into sections. Further work could probably be done, possibly including alphabetizing, creating subsections of the "Mathematical concepts" section, further refining the organization, and other things. Some of our lists of (pardon the expression) "namesakes" are organized this way, and I think some are not. Some of those that are not might benefit from such work. Michael Hardy (talk) 14:28, 26 April 2013 (UTC)

Help needed on Tessellation

This is a request for assistance on Tessellation, which has been in a scrappy state for some years. There are clearly several aspects of the mathematics of the subject (such as in higher dimensions, and of non-Euclidean surfaces) that need proper treatment with decent visual examples, citations and intelligible explanation. I have done some work on the basics and on the artistic and historical side, but a mathematician's hand is now required. I'm happy to lend a hand where I can. Chiswick Chap (talk) 15:48, 26 April 2013 (UTC)

Reference spam at Pursuit-evasion

An editor at Pursuit-evasion is adding references that are not used in the text and appear likely to be a conflict of interest. Are they sufficiently significant in the history of this topic to keep in the article? If not, could I have some help keeping them out, please? —David Eppstein (talk) 17:30, 26 April 2013 (UTC)

Ha, and of course one of the references added would be a paper in Chaos, Solitons & Fractals, wouldn't it? --JBL (talk) 22:14, 26 April 2013 (UTC)
I skimmed the two papers that Chiswick Chap reverted. Both concern differential games with a particular dynamics and constraints and the conditions for successful pursuit. My best guess (I know a little about the field, but am far from an expert) is that these are nice little problems, but are not of fundamental significance to different games theory. The papers themselves don't seem to have any bearing on the article. GScholar shows that each paper has 2 citations, and one was published in 1999. I have to agree, this looks like COI and refspam. --Mark viking (talk) 23:00, 26 April 2013 (UTC)

Hurwitz's theorem and related articles

This discussion has been closed. Please do not modify it.
The following discussion has been closed. Please do not modify it.

There are discussions taking place about the article Hurwitz's theorem (normed division algebras) and the redirect Hurwitz algebra. A Hurwitz algebra is synonymous with a composition algebra on which there is an existing article (except that a few authors do not require composition algebras to be unital). However, it is claimed that Hurwitz algebra should not redirect to composition algebra but to the related Hurwitz's theorem (normed division algebras) on the grounds that composition algebra is "inadequate" , and "There is no content in the Composition algebra article" . Comments of expert editors would be helpful at Talk:Hurwitz_algebra and Talk:Hurwitz's theorem (normed division algebras). Deltahedron (talk) 17:09, 29 April 2013 (UTC) Update: Hurwitz's theorem (normed division algebras) has just been moved to Hurwitz's theorem (composition algebras). Deltahedron (talk) 18:16, 29 April 2013 (UTC) Further update: anyone looking for the discussions will need to look at both Talk:Hurwitz's theorem (composition algebras) (plural) and Talk:Hurwitz's theorem (composition algebra) (singular) as something odd seems to have happened to the redirections. Deltahedron (talk) 19:35, 29 April 2013 (UTC)

As you have noticed, the other editor is a bit prickly, but it is very likely that what they have said is accurate (and he has written a large number of high quality articles). You will get much better results by asking questions and considering the replies. Johnuniq (talk) 03:22, 30 April 2013 (UTC)
I cannot see that this complaint will serve any purpose, except that Deltahedron might discover that I am among the main content contributors to mathematics articles on wikipedia. I don't accept his claims, which contradict what can be found in standard textbooks. My own view, after having seen him "in action", is that he is not very much in touch with this subject and is being pedantic, while showing almost no interest in adding any serious content. So far in his relatively short wikipedia existence, he has created several short stubs. He apparently has no experience with extended content. Even professionally trained mathematicians have to use sources, in-line citations, etc. Misplaced Pages is not a source and cannot invent its own rules for mathematical naming, particularly for interdisciplinary subjects such as this one, which is extensively used in geometry and analysis. On the talk page of the article I mention three sources—Jacobson, Faraut & Koranyi and Springer & Veldkamp. All of these are solid sources. What I have written conforms to those sources. In addition, apart from looking at many other books and articles, I read through the long and fascinating book of Daniel Shapiro, essentially on just this topic. Shapiro gives a very detailed account of the history in the zeroth chapter. What I have written in the article reflects that history quite closely and accurately. In particular in his second posthumous article, which I have read and which was icidentally proofread by L. E. Dickson prior to publiscation, Hurwitz introduces the representation of the real Clifford algebra that appeared in later treatments (e.g. Eckmann, Lee, Chevalley). If I were less busy with symmetric cones, the article that required a detailed account of Euclidean Hurwitz algebras, I would summarise that zeroth chapter in the current article. Much of the material is already there in the main body, but it would do no harm to mention the more general Hurwitz matrix systems and the corresponding problem for composition of forms. I also think that a "further directions" section right at the end could be worthwhile. Shapiro discusses the applications to vector fields on spheres, Bott generators in K-theory, composition of quadratic forms in arbitrary characteristic, generalizations of composition algebras, algebraic K-theory, and so on. A short summary of what can be found in this long and fascinating book would be nice. It also has Conway's treatment of composition algebras (a sort of Archimedeans talk I assume). There are other similar general sources, e.g. the AMS Notices article by Eckmann. Worrying about whether the octonions are a real division algebra or a composition algebra is hardly the point. When Jordan, von Neumann and Wigner used Hurwitz's work in 1934, it was through the system of Clifford matrices that Hurwitz defined. These mathematical physicists did not use the terminology "Jordan algebras", but the quantum mechanics term "r-numbers". I have no idea why Deltahedron has become side-tracked by these minor and trifling MOS-issues. He appears to be making very few substantial content contributions. I have encouraged him to get some experience of writing an extended article so that he has a clearer idea of the relation between the main body of an article and its lede. That would clarify how we rely on sources for writing wikipedia articles, even in mathematics. Bristling, acerbic or whatever you like, those are the rules. A brief look at WP:DTTR might also be an idea. Thanks, Mathsci (talk) 11:29, 30 April 2013 (UTC)

I don't really care one way or the other. It's particularly hard for a non-expert to get any kind of informed opinion when the discussion is spread over so many different pages. Let me say that both editors involved might do best to step back from the matter of what should redirect where. It simply is not a big issue either way, and it's certainly not worthy of User:Mathsci personalizing it so much. Enough time has been wasted on this trifling question, time that could have been spent far more productively. My perhaps naive view is: Composition algebra should have a link to Hurwitz's theorem (composition algebras) and vice versa. If a reader lands at the "wrong" article via the redirect, then it should be made as easy as possible for the reader to find the "right" article. Sławomir Biały (talk) 12:07, 30 April 2013 (UTC)

Yes, both articles have been linked to each other since the second one was created. I do object to my time being wasted on these trivial matters, when I am in the middle of editing. Mathsci (talk) 12:51, 30 April 2013 (UTC)

After all this it will be obvious why I have decided to retire from the project. Deltahedron (talk) 18:35, 1 May 2013 (UTC)

You know, it doesn't have to end like this. (of course, that would apply to many Shakespeare stuff too.) -- Taku (talk) 00:22, 2 May 2013 (UTC)
<comments of community banned user redacted - please do not restore per this arbcom motion>

I regret Deltahedron decision, and I hope he will reconsider his decision and come back to the project. WP has not enough good editors in mathematics. I particularly regret that this decision is caused by the inadequate behavior and the personal attacks of another experienced editor (auto proclamed "main content contributor in mathematics") that systematically breaks WP rules to push his point of view. The remaining of this post is devoted to clarify my appreciation of Mathsci's behavior.

I have just restored Castello Orsini-Odescalchi's post that user:Mathsci has removed with summary edit: "WP:DENY see Misplaced Pages:Sockpuppet investigations/Echigo mole". This WP:SPI concerning User:Castello Orsini-Odescalchi has been started by user:Mathsci himself, and, apparently Mathsci considers that this allows him to censure another editor. When I wrote this sentence and I reverted Mathsci's edit, the decision to consider Castello Orsini-Odescalchi's account as a sockpuppet and to block it was not yet taken. D.Lazard (talk) 17:11, 2 May 2013 (UTC)

Castello Orsini-Odescalchi's post draws our attention on another break of WP:TALKO by Mathsci, who has removed as personal attack from talk:Deltahedron the explanations by Deltahedron of his decision. The removed text does not contain any personal attack, only a description of Mathsci behavior on WP.

On the other hand, above Mathsci's post is full of personal attacks ("he is not very much in touch with this subject and is being pedantic, while showing almost no interest in adding any serious content", "He appears to be making very few substantial content contributions"). About this last attack, Mathsci seems to consider that deep mathematics are more important in WP than encyclopedic content, as I am unable to understand "substantial content" otherwise than "deep mathematics content".

About the content of the discussion, I have no opinion, or more exactly, I have an opinion that is similar to that of User:Sławomir Biały. However Mathsci's posts suggest that he want to deny to other editors, less good mathematicians than himself, the right to edit his own articles. WP:OWN is another rule that Mathsci has forgotten.

D.Lazard (talk) 10:51, 2 May 2013 (UTC)

There are no ownership issues involved here. Deltahedron over-reacted and misunderstaood the purpose of a lede. In the case of an extended article, rather than a stub, it should summarise the article in a way that is accessible to the reader. Objections about a trivial naming issue (composition algebra or normed division algebra) were raised even before the initial draft of the article had been completed. Deltahedron then changed the lede so that it bore no relation to the article (a simple redirect that I changed into a fully fledged article). Clifford algebras and representations of finite groups, etc, are almost always first studied or taught over the real or complex numbers. Taking arbitrary coefficients can be done later, but that is rarely done in the first instance. So when the body of an article is about real vector spaces and real quadratic forms, coming from inner products in this case, there is no reason to change the lede to cover fields of arbitrary characteristic. As far as I could tell, Deltahedron's contributions to the lede were unsourced, apart from his own thoughts together with references to other WP articles. However, there were sources, as mentioned above, and it is those that were used (particularly Shapiro) for any kind of historical remarks. Back in 2006 there was a way of writing mathematical articles without sources or inline citations. That is no longer the case. There is no reason to editorialise or make anachronistic remarks in the lede (that's WP:OR and WP:SYNTH), instead of summarising the article. As far as I am aware no content was actually being discussed. I realise that in the world of real or complex semisimple Jordan algebras, R, C, H and O play the same role as division algebras in the classical theory of central simple algebras. Fhis is a tiny part of a much larger theory which I decided to detach when writing it, since it is one of the few self-contained parts of the general theory (it took just 1 or 2 days to write within several weeks for the rest). As TauyaMurata has pointed out, Deltahedron has over-reacted. TakuyaMurata has edited some of the new set of articles, all of them related to Hermitian symmetric spaces. Mathsci (talk) 12:09, 2 May 2013 (UTC)
I'm frequently seeing Mathsci's name in places like WP:AN and WP:ANI He seems to have a certain attraction to trouble. I've not paid that much attention to these cases but if his actions result in the loss of a good mathematical editor then that is an overall loss to the project. Some of the discussion at Talk:Hurwitz algebra do show some signs of ] "My advice is to wait until I have finished adding the content on Jordan algebras." Our documents are live so anyone can add content at any time. It mathsci wants to work on a draft in userspace that fine. I would not say this is a bad example of WP:OWN but does show a failure of working together. I'm also concern at how rapidly mathsci removes content critical of him, it might be better to let others do this.--Salix (talk): 12:32, 2 May 2013 (UTC)
You're "frequently seeing my name"? Really? Go and substantiate things instead of inventing this kind of nonsensical blather. Have you looked at my content editing history? There is no recent block log but a long list of specialist mathematics articles. So we have your wild and inane accusations, which were written without having checked anything, like a small child. Why are you attacking a major content contributor? What is true is that a number of users have been banned or site-banned from wikipedia for reasons unconnected with mathematics article. Many of them have made false accusations concering me. The banned users include all the sockpuppets of Mikemikev and Echigo mole. Others include Captain Occam, TrevelyanL85A2, Zeromus1 and Ferahgo the Assassin. Another recent contributor to this page was the editor Boodlepounce, who now turns out to be a sockpuppet of Echigo mole, a community banned user. Echigo mole, either posing as Algebraic Jordanian or the tongue-tied buffoon Boodlepounce, was out of his depth in these postgraduate mathematics articles. Both sockpuppets are now blocked. That is how the cookie crumbles. Mathsci (talk) 21:04, 5 May 2013 (UTC)
The wiki (namely, Misplaced Pages) is, generally, a rough media. A user (namely, Deltahedron) who apparently collapsed after a couple of personal attacks from another single user, probably, would not live here for long in any other occurrence. But the recent development shows that our community can (and should) deflect Mathsci’s efforts to disregard and shun any criticism of his edits and attitudes, which rises in Misplaced Pages from time to time. Incnis Mrsi (talk) 13:35, 2 May 2013 (UTC)

What does the community think about this removal of an ambox? Anybody can certify that I tried to discuss the matter (the link is accessible from the complementary ambox at composition algebra), not just pushed my agenda. What should I do: to push until the opponent started to explain his position? Incnis Mrsi (talk) 08:17, 5 May 2013 (UTC)

Please read Faraut & Koranyi. It doesn't take a lot of intelligence to work out that Joe Wolf and Adam Koranyi have been among the major contributors to Hermitian symmetric spaces. My impression from the current lamentable state of the article Jordan algebra is that there is a huge lack of expertise in this area on wikipedia. Sad but true. Your own comments are an example of that. As another example, take the quadratic representation of Jordan algebras or even the definition of quadratic Jordan algebra, a redlink. I have added some content on that in symmetric cone#Quadratic representation. But it cannot be found anywhere else on wkipedia. That is the problem. If you can't be bothered to read Faraut & Koranyo, why make any comment at all? All you're doing is making malicious and sneering remarks about a major contributor. Please stop it. Mathsci (talk) 21:19, 5 May 2013 (UTC)
Except for unexplained removal of my subsection header (which facilitated editing), proposals to learn so-and-such sources about a dozen of related concepts, and usual personal remarks, will we see something about specifically composition algebra and Hurwitz algebra (edit | talk | history | links | watch | logs) today? I repeat: the composition algebra article is short of content, while the Hurwitz's theorem (composition algebras) discusses properties of composition algebras unspecific to the real numbers field. I would willingly learn what aforementioned Wolf, Faraut, and Koranyi (or Koranyo?) think about concretely this matter, even in Mathsci’s paraphrase, but I do not see any reason to divert attention to Jordan algebras and related red links to resolve this concrete conflict. It arose about redirecting "Hurwitz algebra" to either "composition algebra" or "Hurwitz's theorem". Incnis Mrsi (talk) 06:57, 6 May 2013 (UTC)
Comments by suspected sockpuppetes removed.--Salix (talk): 07:32, 6 May 2013 (UTC)

Direct relation

Should the article titled direct relation exist? Or should it redirect to a section of proportionality (mathematics)? Or something else? I imagine some people can think of meanings of this term in mathematics other than direct proportionality. Michael Hardy (talk) 00:01, 1 May 2013 (UTC)

Redirect to proportionality (mathematics)#Direct proportionality seems like a simple and effective solution but others are welcome to disagree. M∧ŜcħεИτlk 00:25, 1 May 2013 (UTC)
Agreed. Also, what's up with the italicization in the lead of that section? --JBL (talk) 01:38, 1 May 2013 (UTC)
The genesis of this article is interesting; this edit completely changed the topic. Should the old version of the article (about something much vaguer) exist? --JBL (talk) 01:43, 1 May 2013 (UTC)

Misplaced Pages:Disambiguation pages with links/May 2013

I would like to thank the members of this project for your help with mathematics-related disambiguation pages. The list of top-linked pages for May is up, and other than Normed division algebra (with only 19 links), I don't see anything off the bat that is a clear math dab. Still, I would appreciate if some members of this project would glance over the disambig project page and see if there are any other math-related disambig pages to be addressed. Cheers! bd2412 T 02:55, 1 May 2013 (UTC)

Looking at the first 500 or so, terms that I noticed that have some mathematical significance are Likelihood ratio, Singularity, Fitting, Density (disambiguation), Dilation, Rectilinear, Recurrence, Rigidity, Transfinite, and Transition function. --Mark viking (talk) 03:16, 1 May 2013 (UTC)
It seems I missed quite a few. Thank you for checking! bd2412 T 04:13, 1 May 2013 (UTC)

Multiplicative calculus

Multiplicative calculus is the work of a single editor and is essentially a redux of the deleted non-Newtonian calculus. It has recently grown to a whopping 59000 bits. Somebody should keep an eye on this. Tkuvho (talk) 10:30, 1 May 2013 (UTC)

I do wish they would just write that Multiplicative calculus article well instead of having a scrappy intro and justification and turning it into a dumping ground for every reference and trivial fact. That sort of thing is uninformative and deters anyone else from contributing or improving. And sticking in references elsewhere in Misplaced Pages which are just advocating the methods instead of directly relevant ones cited by people in the field is just annoying too. The article is correctly in Misplaced Pages and could be made interesting but it is just a dump currently. Dmcq (talk) 12:17, 1 May 2013 (UTC)
Smithpith (talk · contribs) is probably hoping that a large-enough pile of references will prevent his article from being deleted again.
To my way of thinking, it is merely annoying and unnecessary, but probably not harmful. JRSpriggs (talk) 14:18, 1 May 2013 (UTC)
I wish we could just delete this garbage and ban User:Smithpith. His only contribution is his endless self-promotion of this trivial, useless idea, and I'm tired of it. Ozob (talk) 01:24, 2 May 2013 (UTC)
Actually I don't recall this aspect of it. Is User:Smithpith identifiable with one of the authors of "non-Newtonian calculus"? Tkuvho (talk) 08:49, 2 May 2013 (UTC)
Now I see that he signed his name "Michael Grossman" on his talkpage. Tkuvho (talk) 08:51, 2 May 2013 (UTC)
Note that "non-Newtonian calculus", by M. Grossman and R. Katz, earned a whopping 4 citations at MathSciNet since 1972. Tkuvho (talk) 08:53, 2 May 2013 (UTC)
I'm surprised they got that as it looks self published to me, and the editions for sale have a single review by... wait for it... Smithpith. The topic multiplicative calculus is I believe notable enough for inclusion, it is the mess there like a magpies nest that is annoying. Dmcq (talk) 12:23, 2 May 2013 (UTC)
I agree that it's a notable topic. I don't think the Grossman and Katz source should be assigned much weight in that article. Unfortunately, the primary editor of that article has a clear conflict of interests. Someone should root out the dubious references there, eliminate the non-encyclopedic "reception" section, and keep only what can be attributed to reliable secondary sources. Sławomir Biały (talk) 13:26, 2 May 2013 (UTC)
A few months ago the page was a redirect to Product integral where Volterra's work is discussed. Does multiplicative calculus have notability beyond that? Tkuvho (talk) 13:34, 2 May 2013 (UTC)

speaking of product integrals . . .

Can someone add something on product integrals of matrix-valued functions to that article? If it's only about real-valued functions, isn't it essentially instantly reducible to familiar integrals? Michael Hardy (talk) 15:48, 4 May 2013 (UTC)

Rewrite of Quadratic equation

A significant rewrite of Quadratic equation has occurred over the last two weeks. I don't have the time to look into this in any detail, but at first glance there seem to be some problems. Most odd to me is the removal the section titled "Quadratic formula", as well as any mention of the Quadratic formula from the lead. Also note the non-encyclopedic tone in "For most students, factoring by inspection is the first method of solving quadratic equations ..." What do others think? Paul August ☎ 19:01, 2 May 2013 (UTC)

On the whole, I think we can work with the article in its present form. However, one thing I disagree strongly with is the apparent ghettoization of certain important topics to an "Advanced topics" section. This clearly violates some of our basic principles. Also, obviously the article should state the quadratic formula clearly before deriving it. I think that all of the derivations of this formula should be collected into the same section. If the objective is for earlier sections to be more of an elementary reference, then the earlier sections should not contain derivations. And language specific to the field of education should be confined to a section on education, I think. Sławomir Biały (talk) 19:20, 2 May 2013 (UTC)
Lol "ghettorization". Mct mht (talk) 19:53, 2 May 2013 (UTC)

"Great Feuds in Mathematics" (book)

Would anyone in this WikiProject like to write a Misplaced Pages article about this book?

—Wavelength (talk) 20:58, 2 May 2013 (UTC)

There's no obvious indication that this book passes WP:Notability (books). Sławomir Biały (talk) 21:25, 2 May 2013 (UTC)
Here are two independent reviews of the book.
—Wavelength (talk) 00:04, 3 May 2013 (UTC)
The NASW review doesn't look very substantial, but there's a also third review at MR2248901, a fourth (behind a paywall that I don't have access to) at Vinculum, a fifth at Journal of the British Society for the History of Mathematics, and a sixth at Science News.—David Eppstein (talk) 00:38, 3 May 2013 (UTC)

Associative algebra #Representations

Such section could be topical without any doubt, but its current content appears to be, at best, misplaced. Incnis Mrsi (talk) 17:47, 3 May 2013 (UTC)

It's a duplicate of Algebra representation and, as usual, should be merged with it except leaving a short paragraph or two. -- Taku (talk) 18:51, 3 May 2013 (UTC)
What does your "duplicate" denote? I do not capture your thought. BTW, the content IMHO can be moved into representation theory. Incnis Mrsi (talk) 19:58, 3 May 2013 (UTC)
English grammar is tricky, isn't it? I meant that section and the article Algebra representation, at first glance, seem like the same topic. The section is about the compatibility conditions; for example, an associate algebra has a natural structure of Lie algebra (i.e., commutator) and so we can look at how two structures are related. I don't know why the discussion is limited to representations (an expert would know), but I don't think it should be merged with representation theory. Perhaps we need tensor product of representations. (the solution is always more stuff.) -- Taku (talk) 13:20, 4 May 2013 (UTC)

Symbol Definitions

A lot of articles use mathematical symbols that I don't remember, or have never seen before. Since they're special characters, they can't be searched. It would be nice if every such symbol was automatically a hyperlink to the page defining it. --70.199.133.145 (talk) 01:38, 4 May 2013 (UTC)

There is List of mathematical symbols and Mathematical operators and symbols in Unicode. Many unicode characters are linked to the corresponding article, is there a specific one your interested in?--Salix (talk): 03:30, 4 May 2013 (UTC)
Salix has provided some useful resources for looking up symbols. But those sources suggest an important point--that any given symbol can represent different things in different contexts. As much as possible, we should strive to explain at first use any notation we use in the math articles that isn't completely obvious. --Mark viking (talk) 03:44, 4 May 2013 (UTC)
Anon: if you copy and paste an unknown symbol into the Misplaced Pages search box, you can search on it just fine. Many symbols will have an article that explains their meaning. But, I agree with Mark that unobvious symbols should be explained and linked on first use in any given article.--Srleffler (talk) 05:34, 4 May 2013 (UTC)
Misplaced Pages’s use of the goddamned lucene-search already created a local myth that “special characters can't be searched”. Happily, MediaWiki’s search dialog itself does not depend on lucene with its blatant discrimination against non-letter characters, and may retrieve titles containing whatever characters: even U+0085. Incnis Mrsi (talk) 12:19, 4 May 2013 (UTC)

Misplaced Pages talk:Articles for creation/Vector Manifold

Dear mathemeticians:

There is an article Misplaced Pages talk:Articles for creation/Vector Manifold in the Afc just now that could use some attention from someone with mathematical knowledge. —Anne Delong (talk) 01:40, 5 May 2013 (UTC)

Icnis Msri cannot follow an argument

An amazing argument over the so named lengthy in-depth article: see talk: Hurwitz's theorem (composition algebras) #L(a*) = L(a)* and similar. Ironically, the editor who recently removed my ambox as per sources is himself found to distort the notation of Faraut & Koranyi beyond recognition. Incnis Mrsi (talk) 13:14, 6 May 2013 (UTC)

Why post this nonsense when (a) you just made a stupid undergraduate/highschool mistake (poor guesswork) (b) you didn't lift a finger to check the source (b) you did not read what the article said (d) you did not look at my reply. Since you cannot be bothered to read my replies here is the explanation. The inner product on quaternions is Re ab*= Re b*a. So

(L(a)b,c) = Re c*ab= Re (a*c)*b = (b,L(a*)c). So L(a)* = L(a)* by the definition of adjoint on a finite dimensional real inner product space. Why are wasting time like this and making such silly errors? Mathsci (talk) 13:28, 6 May 2013 (UTC)