Wikipedia talk:WikiProject Mathematics/Archive/2006/Oct

message: I wonder if anybody knowing the subject of the articles edited by WATARU could take a look at some diffs and see if it makes sense what he wrote. Oleg Alexandrov (talk) 15:09, 28 September 2006 (UTC)
replies: text: I think all changes but one have been corrected or removed.  I don't know about Japanese sociologists.  — Arthur Rubin |  (talk) 18:15, 28 September 2006 (UTC)
replies: text:  But he doesn't stop, blocking him seems necessary.--gwaihir 23:37, 28 September 2006 (UTC)
replies: text: Looking at policy under WP:DE (Disruptive Editing) I think WATARU is somewhere between steps 5 and 6 of the process.  According to step 4, a 'Request for Comment or other impartial dispute resolution' should be opened.  However this was done back in April '06 . We now seem to have 5, 'Editor ignores consensus'.  The suggestions under part 6 are topic ban, site ban or probation. EdJohnston 00:45, 29 September 2006 (UTC)
replies: text: We reached point 6: 'Blocks fail to solve the problem.'  --LambiamTalk 01:46, 29 September 2006 (UTC)
replies: text: Still up to the same tricks. What's the next step? —David Eppstein 23:15, 30 September 2006 (UTC)
replies: text: Blocked (along with his IP) for 48 hours for personal attack (against me).  I have no objection to a community ban, including the IP.  — Arthur Rubin |  (talk) 06:00, 1 October 2006 (UTC)
replies: text: Changed reason to general disruption.  The WP:NPA in editing my user page doesn't rise to the level required for a block, but the disruption is still valid.  — Arthur Rubin |  (talk) 06:26, 1 October 2006 (UTC)
replies: text:  Now Special:Contributions/Suslin --gwaihir 15:40, 4 October 2006 (UTC)
replies: text:  and Special:Contributions/MACHIDA  (indefblocked; anyone changing the ja: wikilink on Field or Division ring deservices an immediate temporary block, at this point, and the other edits and style makes it clear what's happening.)  — Arthur Rubin |  (talk) 12:54, 9 October 2006 (UTC)
replies: text:  and Special:Contributions/MORI (indefblocked), but he seems to have killed the ja: articles.  — Arthur Rubin |  (talk) 03:10, 10 October 2006 (UTC)
thread_title:  WAREL is back again 

message: Some of us are discussing re-organizing the articles about the fourier transfrom, I thought this might be of general interest, so anyone interested should look at the Topology of articles discussion under the Continuous Fourier transform talk page. — Preceding unsigned comment added by Thenub314 (talk • contribs)  (Oops on my part Thenub314 00:29, 30 September 2006 (UTC)
replies: text: That's not a good page name. How about Fourier transforms on the line? Charles Matthews 07:01, 29 September 2006 (UTC)
replies: text: There is also a multi-dimensional continuous version, which curiously is mentioned at Fourier transform but not Continuous Fourier transform.  --LambiamTalk 11:46, 29 September 2006 (UTC)

text:  The multidimensional version is in there under under a sub-sub-section Extensions. I like the idea of "Fourier Transform on the Line", I had suggested "Fourier Transfrom on R", but no one else seemed to like that idea.  But I do dislike the term "continuous Fourier Transform". Thenub314 13:41, 1 October 2006 (UTC)
thread_title:  Fourier Transform 

message: John Dee is up for a featured article review. Detailed concerns may be found here. Please leave your comments and help us address and maintain this article's featured quality. Sandy 21:02, 1 October 2006 (UTC)
thread_title: [[John Dee]]

message: Geometry is just undergoing a major reworking. The previous article was just a history of the topic and has been moved to History of geometry. This now leaves Geometry as a stub, sugestions of how to structure the article welcome on the talk page. --Salix alba (talk) 09:24, 2 October 2006 (UTC)
replies: text: And this major move had how much discussion? 'Just' a history of geometry - would anyone care to weigh in with a non-historicist discussion of what geometry means? Charles Matthews 09:31, 2 October 2006 (UTC)
replies: text: Er, no discussion. I guess User:The Transhumanist was being WP:BOLD. Still I think its generally a good idea, as the history only approach was not the best way to structure the article. --Salix alba (talk) 10:14, 2 October 2006 (UTC)
replies: text: I agree that the earlier incarnation of the article was bloated and didn't give enough of a flavor of 20th century developments, but jettisoning the whole thing was a mistake. I am definitely leaning in the direction of revert. Michael Kinyon 10:31, 2 October 2006 (UTC)

text: Well, plenty of edits since then. Let it not be said that we (OK, I) ducked the challenge. Charles Matthews 15:02, 2 October 2006 (UTC)
replies: text: I just assumed you meant the "royal we", Charles. :-) In any case, yes, I'm slowly being convinced this can work. Michael Kinyon 15:36, 2 October 2006 (UTC)

text: You can call me Prince. Charles Matthews 17:02, 2 October 2006 (UTC)
replies: text:  Though Shing-shen Chern is deceased (so I guess he's not contemporary), it is very odd that he is not mentioned in this article. What is the definition of contemporary again. A fortiori, Cartan I guess would not be contemporary either. --CSTAR 17:10, 2 October 2006 (UTC)

text: It needs a section just for differential geometry too, of course. Charles Matthews 18:25, 2 October 2006 (UTC)
replies: text: There appears to be a very long list of topics (in its own article) of articles on Geometry, so I do not think that the main article needs to mention them. It already has a pointer to that list. I would suggest that the main article focus on the most modern concept of Geometry, i.e. David Hilbert's. As the History of Geometry article says "In geometry, there was a clear need for a new set of axioms, which would be complete, and which in no way relied on pictures we draw or on our intuition of space. Such axioms were given by David Hilbert in 1894 in his dissertation Grundlagen der Geometrie (Foundations of Geometry).". JRSpriggs 09:18, 3 October 2006 (UTC)
replies: text: Axiomatic geometry is interesting, but is only a small part of the subject known as geometry. The article works best as a survey, and seems to be evolving quite well right now. Michael Kinyon 09:43, 3 October 2006 (UTC)

text: Hilbert's axioms are only 'state of the art' in a very restricted sense. The suggestion that we need a survey based on the contemporary scene is sound; though it shouldn't exclude other things on that page. As for axiomatics, Atiyah says some interesting things about those. I was trying to find where Weil discussed geometry, yesterday, so far without success. The way things are going, we should be finding more quotes to add to various articles. Charles Matthews 09:59, 3 October 2006 (UTC)
replies: text: Hilbert's axioms provide a great understanding of how mathematics develops and how mathematicians think; You can see that reading any good "mathematical education" textbook (quotes here are used to indicate my disdain for most specialists in education), e.g. Great Theorems of Mathematics: A Journey Through Genius (I forgot the author), that puts side to side Euclid's axioms and Hilbert's. They are a valuable addition to any article on geometry. --Lucas Gallindo 15:10, 3 October 2006 (UTC)
replies: text: The author is William Dunham. . Gandalf61 15:22, 3 October 2006 (UTC)

text: I think it is fair to ask how many contemporary papers in geometry are actually based on Hilbert's axioms. Charles Matthews 15:26, 3 October 2006 (UTC)
replies: text: As far as I know, papers of real relevance, using Hilbert axioms... there are none! But I still think they are enlightening for the newcomer.--Lucas Gallindo 15:40, 3 October 2006 (UTC)

text: It is also fair to ask how many contemporary papers are based on Euclid's axioms.  I don't believe the study of facts about Euclidean geometry on the plane is a major topic in contemporary research. The things mentioned in Geometry about contemporary research in Euclidean geometry, such as geometric group theory, seem like a stretch.  CMummert 01:32, 4 October 2006 (UTC)
thread_title:  Major reworking of Geometry 

message: Just a word of warning: The page Numeric spiral was created today by User:Noluz. The same user listed it on List of curves and in the External links of Archimedean spiral, but I just reverted both since Numeric spiral has nothing to do with curves at best, and at worst is numerology. Michael Kinyon 23:29, 3 October 2006 (UTC)
replies: text: Is this the same or similar to the Ulam spiral? --Salix alba (talk) 00:29, 4 October 2006 (UTC)
replies: text: Yes, I think so. It is similar, in fact, to at least one of the external links  on that page. Michael Kinyon 01:55, 4 October 2006 (UTC)
replies: text: The thing described is not a Ulam spiral. It is a badly designed visual representation of partitioning the natural numbers into equivalence classes modulo 9 while marking the prime numbers. Putting them in the form of a spiral serves no particular purpose and does not help to bring to light any properties. I've listed this article for deletion.  --LambiamTalk 05:04, 4 October 2006 (UTC)
replies: text: It is simply applying Casting out nines to calculate the equivalence class (as Lambiam said) and then treating the fact that primes (except three itself) are not divisible by three as some kind of magic. Really idiotic. JRSpriggs 05:36, 4 October 2006 (UTC)

text: Yes, I see it now that I finally thought to click on the figure to enlarge it. And only now can I decipher the nonmagical parts of the article. "Cabilist" indeed! :-) Michael Kinyon 07:01, 4 October 2006 (UTC)
thread_title: [[Numeric spiral]]

message: Hi, it seems that a single-issue user (130.158.83.81) is keen to revert the controversy section of Gang Tian from my edits originally made here. His reversions are here and here. 
My edits were intended to improve the quality of the writing of that section, to improve the wikilinks (for example, 130.158.83.81 insists on linking to Yau-Tian affair, which doesn't exist, rather than Tian-Yau affair), to improve the accuracy (according to my limited knowledge) and to add citation requests for unsupported assertions.
A later editor removed the controversy section altogether, after the 130.158.83.81s latest reversion. I have since restored the section for the time being, but perhaps removal is the best option. If we want to keep the section, then the version promoted by 130.158.83.81 seems objectively worse than my alternative. There is much room for improvement, but I just sought to make the section better than awful.
Anyway, I don't think that editor is breaking any rules, and I don't want to enter a daily edit war, but I thought I'd bring it to your attention. All the best--Jpod2 08:59, 4 October 2006 (UTC)
replies: text: I've made a redirect from Yau-Tian affair, removing one minor bone of contention. The content should be very careful, and adhere to WP:LIVING, staying well away from any hint of defamation. We should also remember and respect the fact that these are important professional mathematicians. Charles Matthews 09:11, 4 October 2006 (UTC)
replies: text: Agreed. I tried to tone down some of the extreme and unusual language in my edit, or otherwise requested citations. I doubt that this version will stay there, though.--Jpod2 09:14, 4 October 2006 (UTC)
replies: text: I think your edits helped to improve the section, and helped to remove POV from the article.  Thanks.  It may be that user Reb's solution of removing the unsourced paragraph may be best for now.  Good luck, Lunch 15:08, 4 October 2006 (UTC)
replies: text: I think that might be the best solution for the moment. All the best--Jpod2 16:31, 4 October 2006 (UTC)

text: Actually I had the impression he was at Princeton, so I did a little searching and it seems he is there now, although a few years ago he was at MIT and transitioning to Princeton.  So this ought to be cleared up in the article.  --C S (Talk) 19:42, 4 October 2006 (UTC)
thread_title: Gang Tian

message: Besides the fairly well-patrolled Poincare conjecture, Grigori Perelman, Tian-Yau affair, Manifold Destiny, and newer Gang Tian, those with the inclination should keep an eye on S.T. Yau (which doesn't appear watched as much) and Sylvia Nasar (not watched very much either).  Recently there has been a couple rather defamatory edits to the Nasar article (based on what appears to be sheer speculation and poor sourcing).  --C S (Talk) 22:30, 4 October 2006 (UTC)
thread_title:  [[Sylvia Nasar]] 

message: The page use to redirect to Lie group  but was changed into a small article which is pretty much barren.--Jersey Devil 10:58, 5 October 2006 (UTC)
replies: text: Looks like it should be merged into Lie (disambiguation); so I did. Septentrionalis 23:01, 5 October 2006 (UTC)
thread_title: [[Lie theory]]

message: Wikipedia:WikiProject Physics/Citation guidelines proposal currently states: "... editors in Wikipedia:WikiProject Physics want to clarify how these guidelines should be implemented for physics articles ...". Question: Can we change that to: "... editors in the WikiProjects Physics and Mathematics want to clarify how these guidelines should be implemented for physics and mathematics articles ..."?  --LambiamTalk 17:20, 5 October 2006 (UTC)
replies: text: I would support that change. Madmath789 17:25, 5 October 2006 (UTC)

text: Me too. I like the proposed guidelines a lot. Especially the new part about how simple examples and rederivations aren't WP:OR. —David Eppstein 17:39, 5 October 2006 (UTC)

text: Yeah, I'm in. I like them, too. Michael Kinyon 18:19, 5 October 2006 (UTC)

text: Yes. Editors of the mathematics article are setting citation guidelines for that article. It would be far better to follow more broadly accepted guidelines. --Jtir 18:33, 5 October 2006 (UTC)

text: <comment deleted -- I had said something about the 0.999... article, well I will not delete my comments again> :) --Vesal 20:21, 5 October 2006 (UTC)
replies: text: The proposed guideline gives no examples of book-cites at the page level, which are used extensively in [0.999...]]. Another problem is that the example article-cites appear in a random order in the notes instead of alphabetically. --Jtir 20:16, 5 October 2006 (UTC)
replies: text:  I wrote some confusing stuff up there and deleted it, sorry about it... I will explain, at first I thought it was a citation style, but this is something much deeper, it's the verifiability guideline, and well as such I don't think it specifies any style at all.  So let's discuss the guideline... I have a number of questions, maybe I will ask them on the guidelines talk page.  --Vesal 20:25, 5 October 2006 (UTC)
replies: text: That would be the appropriate place for any and all comments on the draft. Putting them here makes them invisible to editors in other projects. Comments are welcome from everyone. CMummert 20:36, 5 October 2006 (UTC)

text: Has there ever! You only have to check out the talk page of that article and its archives. The general consensus I perceive in hindsight is that mild OR is better than nothing, but I've encountered little resistance to the idea that cited material is better than OR. What do I think about the citing? I think it's hard but worthwhile. Not only does it keep you honest and stem accuracy disputes, the search for citations can lead you to the only really interesting material in an article. Melchoir 21:14, 5 October 2006 (UTC)
replies: text: I have gone ahead and added mathematics in. Seeing as it is a proposal, anyways, it can't hurt. A number of people on WP:CITE and WP:GA seem pretty happy with the proposal too, so I'm optimistic about the chances for this proposal to make an impact for the better. –Joke 21:43, 5 October 2006 (UTC)

text: I'd just like to say I am really glad the difficulties physics and maths articles faced over WP:CITE and WP:GA are being addressed. Tompw 22:28, 5 October 2006 (UTC)
replies: text: I'm glad to see the issue recognized. The unthinking insistence at Wikipedia:What_is_a_good_article%3F that all articles, whatever their structure or sources, must have in-line citations continues, however. The exception in the proposal is entirely reasonable.  Septentrionalis 22:59, 5 October 2006 (UTC)

text: I don't think anything has been resolved at WP:CITE; this is at best a stopgap measure. And WP:GA applications are going to be a dead end for a while unless we get a large number of scientifically knowledgable good article reviewers. CMummert 00:23, 6 October 2006 (UTC)

text: We should write good articles, not Good Articles. The more I see of that process, the less I like it. Septentrionalis 03:47, 6 October 2006 (UTC)
thread_title:  Citation guidelines proposal support 

message: While looking into an OTRS ticket, I came across this edit. Does anyone know if this stuff is accurate? --bainer (talk) 08:31, 6 October 2006 (UTC)
replies: text: Pretty good nonsense. It has been reverted. Charles Matthews 10:16, 6 October 2006 (UTC)
thread_title:  Prime numbers 

message: Graph invariant is a regular page. I propose to make it a subcategory of Graph Theory. Several pages would then belong to it:
* Algebraic connectivity
* Arboricity
* Betti number
* Clustering coefficient
* Colin de Verdière graph invariant
* etc.
Do you agree/disagree? pom 09:22, 6 October 2006 (UTC)
replies: text: On the point of grammar, :Category:Graph invariants would be the usual style. Charles Matthews 10:07, 6 October 2006 (UTC)

text: Agree (preferrably with the plural form) JoergenB 12:49, 6 October 2006 (UTC)

text: On a similar note, I just made a subcat :Category:Graph families yesterday. Probably several of the entries there could also be cross-listed under invariants, e.g. Dense graph defines density as an invariant. —David Eppstein 15:04, 6 October 2006 (UTC)

text: Notable invariants should be worked into the main article as prose, as in Knot invariant. Later on, it may even be useful to complete the coverage with a list article, but not yet. Melchoir 16:32, 6 October 2006 (UTC)
thread_title:  Graph invariant: a new category? 

message: There are several fairly active discussions going on about quality, citations and so on. The Project needs one more thing, really, which is an assessment of coverage and where it is going. At a moment when the coverage as a whole looks satisfactory, saying people should concentrate more on quality makes every sense. 
We are not there yet, really. It is somewhat muddling to look at lists of articles, or of red links, and to try just from that to say how broad the coverage is. My gut feeling, though, is that 18 months ago we were mid-1950s, and now more like mid-1960s. That is, there is a historical way of thinking about this, and it is a helpful barometer. (In physics, the 1960s would be quarks and quasars, kind of thing, and it is not so odd there to ask about coverage in terms of what is adequately discussed in encyclopedia terms.)
Extrapolating, we might have a reasonably full coverage in about four years time. Don't groan: it would be an amazing achievement to say we had a survey that good. There are always going to be topics left out, but the criterion is that writing an article to fill a gap would not involve a long trail of red links to further concepts on which it depended. The basic vocabulary would be there.
Charles Matthews 10:28, 6 October 2006 (UTC)
thread_title: The future

message: I noticed a number of problematic edits by User:Karl-H on topics relating to  the Riemann hypothesis. I tried fixing some, but am out of energy at the moment. I believe that the gist of what he's trying to say is mostly correct, but he is not a native English speaker, and he's not a mathematician, and he's writing up original interpretations of research papers he did not quite understand. The edits wreck to flow of the articles, the language is fractured, ungrammatical, mis-capitalized, and worst: the formulas are fractured, incomplete or wrong; see for example Chebyshev function, Hilbert-Polya conjecture, etc. I just can't get to this stuff in the next few weeks. linas 19:28, 7 October 2006 (UTC)
replies: text: See an awkward ongoing discussion about claims to have proved RH, on Talk: Hilbert-Pólya conjecture. I'm not rushing into anything, but there are unsupported statements about RH on the pages, not sourced, which may need to be removed as original research. There may also be an issue here about what is a 'reliable source' for rumours, how we treat 'non-withdrawn claims' over time, and so on. My view is that in most cases we can have an article with NPOV that ignores fringe claims; so that cutting out rumours is usually OK. Charles Matthews 09:26, 9 October 2006 (UTC)
thread_title:  Problem edits on RH 

message: Whereas I 100% agree with We should write good articles, not Good Articles, I want to bring to everybody's attention that the GA candidateship of Order theory is on hold  for failing the criteria 2a, 2b,2c of It is factually accurate and verifiable. --Pjacobi 22:31, 8 October 2006 (UTC)
replies: text: This is a sad example of the prevailing lunacy. Despite the twisted mindset of some editors that "inline citations" = "accurate and verifiable", this article is well documented. Reputable sources given at the end suffice to allow the claims given in the article to be verified as accurate. Wikipedia must learn that mobs and footnotes are no substitute for editorial competence and diligence. --KSmrqT 23:31, 9 October 2006 (UTC)
thread_title:  [[Order theory]] 

message: The article Euclidean group is a large amount of little factoids, which added together make, in my view, a pain to read. The article is primarily the work of User:Patrick. I like much more the original version by Charles Matthews (see current version and good old version). I would vote for a rewrite of the article using the older version or a revert. Comments? Oleg Alexandrov (talk) 04:23, 13 October 2006 (UTC)
replies: text: Wikipedia:Embedded list is relevant, I think. (I'm guilty of perpetrating lists sometimes as well, but that doesn't mean I think it's generally good style.) —David Eppstein 04:49, 13 October 2006 (UTC)

text: I always support good writing over grab bags; please do revert and rewrite. --KSmrqT 05:18, 13 October 2006 (UTC)

text: I think I added a lot of useful content, in a very orderly way, not as an unorganized collection of factoids. Therefore I am against deleting that. We should be careful in changing lists into prose, it may become less readable (or if we do, keep both, and split off parts if the article gets too long). Constructive input from others would be nice, there has been little activity by others the last year.--Patrick 07:58, 13 October 2006 (UTC)
replies: text: The new version does have a lot more information, but when I read through it I found it to be very staccato.    Some of the lists are clear, but for example the overview of isometries section is very difficult to follow.  I don't think a revert is justified, just some editing to make the article flow better.  Adding introductory paragraphs to some of the sectins would make the lists more clear, while other lists could be replaced with a series of subsections. CMummert 13:46, 13 October 2006 (UTC)

text: If the overview is restricted to closed subgroups this has to be mentioned, you cannot say the subgroups are all of type A, B, or C, when there is also a type D. However, to clarify the restriction you have to explain it, so you end up briefly explaining the additional kind anyway.--Patrick 22:08, 13 October 2006 (UTC)
replies: text: I don't agree: if it is thought of as a topological group, why not just explain the closed subgroups? I don't see the need for any more than that. Charles Matthews 12:23, 14 October 2006 (UTC)

text: Doesn't this all belong on the talk page Talk:Euclidean group? Let's take it there. CMummert 22:22, 13 October 2006 (UTC)
replies: text:  Good point. I started the discussion here to attract attention, now that people got involved, the discussion can continue on the appropriate talk page. Oleg Alexandrov (talk) 02:29, 14 October 2006 (UTC)
thread_title:  Euclidean group 

message: The categories :Category:Erdős number 1 etc. (not to be confused with :Category:Wikipedians with Erdős number 1) are nominated for deletion. If you have an opinion on this, comment on Wikipedia:Categories for deletion/Log/2006 October 8#Erdős number categories. You probably have to be fast, as the nomination was six days ago. -- Jitse Niesen (talk) 05:40, 14 October 2006 (UTC)
thread_title:  Erdős number categories on CfD 

message: I observe that this article has (recently, I believe) become congested with umlauts. Unless, as we are not likely to, we change the spelling of Noetherian ring, this should be straightened out, with a reasonable allowance of "Noether"s for a mathematician who is usually so called in English, and who died on the faculty of Bryn Mawr College. Septentrionalis 15:36, 16 October 2006 (UTC)
replies: text: And, if I may add, the German Wikipedia also spells the name :de:Emmy Noether. So do German libraries, like the catalogue of the Deutsche Nationalbibliothek. And so did she herself. I'm copying this over to the talk page of the article.  --LambiamTalk 16:45, 16 October 2006 (UTC)
thread_title: [[Emmy Noether]]

message: If your expertise allows you to contribute in a meaningful way to articles involving Hamiltonians and their applications, please take a look at Wikipedia talk:WikiProject Physics#Hamiltonian articles.  --LambiamTalk 01:35, 17 October 2006 (UTC)
thread_title:  Hamiltonian, anyone? 

message: There are currently no articles or subcategories in :Category:Infinity paradoxes which is a subcategory of :Category:Infinity. Possibly related articles are in :Category:Paradoxes of naive set theory which is in :Category:Basic concepts in infinite set theory which is in :Category:Infinity. Does anyone want to put something in the empty category or shall we delete it? JRSpriggs 08:17, 16 October 2006 (UTC)
replies: text: I say nominate for deletion. :Category:Mathematics paradoxes is a reasonable upper bound, and the :Category:Paradoxes of naive set theory was deliberately created to sort out those relevant to infinite cardinality. Charles Matthews 13:09, 16 October 2006 (UTC)
replies: text: If I understand the rules correctly, I can add  to the category on 20 October 2006. Will that result in it being deleted? Or must I also list it somewhere? JRSpriggs 05:55, 17 October 2006 (UTC)
replies: text: No, just speedy it. It's not like deleting an empty category is a big deal; if someone wants to recreate it, it takes all of five seconds. Melchoir 06:29, 17 October 2006 (UTC)
replies: text: Although I have suggested (on this page) deleting a category once before, I have never gone thru the process myself. As I understand it, I would have to persuade an administrator to delete it. Do I just ask one, like User talk:Oleg Alexandrov or User talk:Arthur Rubin? JRSpriggs 07:59, 17 October 2006 (UTC)

text: is actually a a speedy tag. Basically just put it on the page and wait. If no one objects it will go.  WP:CSD explains more. --Salix alba (talk) 08:24, 17 October 2006 (UTC)
thread_title:  Another empty category 

message: I've added "eigendecomposition" as a synonym for "spectral decomposition" in the spectral theorem article: I'm almost completely sure that's right, but my maths is a bit rusty these days -- could someone more up-to-date double-check this, please? -- The Anome 11:59, 20 October 2006 (UTC)
replies: text: Aaagh: Google says 84K of hits for eigendecomposition. That's already far too many ... Charles Matthews 15:43, 20 October 2006 (UTC)
thread_title:  Eigendecomposition 

message: Since the discussions seem to have abated for some time now, I am asking the Mathematics and Physics WikiProjects if they support the new citation guidelines that I (and others) have devised. The point of the guidelines is to establish an appropriate, sensible standard for referencing articles in our fields so that we are less likely to run into objections (such as those that have come up recently) when we try to write technical articles that others then tell us are impropoerly sourced. I think these guidelines are now well thought out enough that they can be added to the main pages of the two WikiProjects and perhaps linked from WP:CITE. I should also note that they seem to have attracted some encouragement from outside the WikiProjects, on their talk page, mine, and on WP:CITE.
One outstanding issue is where to move the page. I don't have any great ideas. Wikipedia:WikiProjects Mathematics and Physics/Citation guidelines is too cumbersome. We could just leave it under physics as Wikipedia:WikiProject Physics/Citation guidelines or be BOLD and put it at Wikipedia:Scientific citation guidelines (presumably this would mean we would have to engage with the rest of the community to ensure there is consensus). I submit we should go with Wikipedia:WikiProject Physics/Citation guidelines and once we have consensus here go to Wikipedia:WikiProject Biology and Wikipedia:WikiProject Chemistry (and wherever else seems appropriate) to solicit their opinions, and then move it out of the physics WikiProject. We could even eventually go ask the wider Wikipedia community what they think at WP:CITE but I think that should be left as a longer term project. –Joke 22:14, 16 October 2006 (UTC)
replies: text: Since there doesn't seem to be any objection to this proposal, I have gone ahead and moved it to Wikipedia:Scientific citation guidelines and added links on the pages of the relevant WikiProjects and on WP:CITE. –Joke 03:52, 26 October 2006 (UTC)
thread_title:  Citation guidelines proposal 

message: Hello. The WikiProject Council has recently updated the Wikipedia:WikiProject Council/Directory.  This new directory includes a variety of categories and subcategories which will, with luck, potentially draw new members to the projects who are interested in those specific subjects. Please review the directory and make any changes to the entries for your project that you see fit. There is also a directory of portals, at User:B2T2/Portal, listing all the existing portals. Feel free to add any of them to the portals or comments section of your entries in the directory. The three columns regarding assessment, peer review, and collaboration are included in the directory for both the use of the projects themselves and for that of others. Having such departments will allow a project to more quickly and easily identify its most important articles and its articles in greatest need of improvement. If you have not already done so, please consider whether your project would benefit from having departments which deal in these matters. It is my hope that all the changes to the directory can be finished by the first of next month. Please feel free to make any changes you see fit to the entries for your project before then. If you should have any questions regarding this matter, please do not hesitate to contact me. Thank you.  B2T2 00:20, 26 October 2006 (UTC)
thread_title:  Project directory 

message: The various mathematician-stub templates are currently being discussed at Wikipedia:Stub types for deletion/Log/2006/October/19
Affected templates , , , . --Salix alba (talk) 11:32, 26 October 2006 (UTC)
thread_title:  mathematician-stub 

message: I was fiddling with some formulas, and seem to have stumbled over the following theorem: given any topological space X and any homomorphism g:X\to X, there exists a measure \mu such that it is preserved by the pushforward g_* \mu=\mu (aka the direct image functor on the category of measurable spaces(?)); equivalently, there is always a measure such that g is a measure-preserving map, and furthermore, this measure is unique. This theorem is little more than a fancy-pants version of the Frobenius-Perron theorem, and the measure is more or less the Haar measure.  I was wondering if this theorem has a name? Is it in textbooks? Or is it supposed to be a nameless corollary of the theorem that defines the Haar measure? Thanks. linas 03:35, 21 October 2006 (UTC)
replies: text: I find uniqueness hard to believe. JRSpriggs 06:40, 21 October 2006 (UTC)

text: I question existence, since Haar measure depends on having a group structure. --KSmrqT 12:29, 21 October 2006 (UTC)

text: Existence is true if X is a compact space, in which case the measure μ can be taken to be a probability measure. This is just the compactness of the space of Borel probability measures in the weak* topology and the fact the group of integers Z is amenable (actually this is equivalent to a fixed point theorem for continuous affine mappings on compact convex sets. See Dunford Schwartz, although I don't have it in front of me so I don't know the exact formulation.) However, in general uniqueness is false even for compact X and imposing the additional requirement that the measure μ is a probability measure.  Uniqueness is a special property called unique ergodicity. For non-compact X, existence is also false without some additional assumption on X.--CSTAR 16:08, 21 October 2006 (UTC)
replies: text: Thank you CSTAR, this pointer is just what I needed. (My X was indeed compact, and my g ergodic. I'm not sure what other additional errors assumptions I might have accidentally made along the way.) KSmrq, I'm looking at dynamical systems, so the hand-waving physics argument for existence is that physical systems always have a ground state, and, for systems in thermodynamic equilibrium (i.e. ergodic), so that all symmetries are broken, the ground state is unique. I'm grappling with general formulations, but this is new territory to me. I assume "Dunford Schwartz" is the book "Linear Operators" from 1958. I presume newer books on operator theory will have similar content. linas 22:17, 21 October 2006 (UTC)
replies: text:  Dunford and Schwartz vols 1 and 2 (vol 3 is much less interesting), though dated, are unsurpassed as general references in functional analysis.--CSTAR 22:30, 21 October 2006 (UTC)
replies: text: Someone creted an artcle just today, for at least half of what I was looking for: the Krylov-Bogolyubov theorem. linas 23:48, 26 October 2006 (UTC)
thread_title:  Name of theorem? 

message: I've mentioned this before, but I want to get it implemented now.  See MediaWiki talk:Common.css#span.texhtml. —Mets501 (talk) 21:48, 28 October 2006 (UTC)
replies: text: Yes, you've suggested it before. And then, as now, the answer is that you can make it happen in your own personal style sheet, called monobook.css. (See Help:User style or Wikipedia:Help desk.) There is no point in wasting our time again, and certainly not developers' time, with this. The new STIX fonts will be serif fonts, and we'd like to switch over to blahtex as soon as possible. --KSmrqT 22:58, 28 October 2006 (UTC)
thread_title:  [[MediaWiki talk:Common.css#span.texhtml]]