View source for Wiki143 talk:WikiProject Mathematics/Archive/2005/Jun-Jul

{{WikiProject Mathematics archive list}}

==Featured list nomination==

Please see [[Wikipedia:Featured_list_candidates#Nominations]].

I have nominated [[list of lists of mathematical topics]] ('''not to be confused with''' [[list of mathematical topics]]) to be a featured list.  Please go to that nomination page to vote for or against it. [[User:Michael Hardy|Michael Hardy]] 01:22, 1 Jun 2005 (UTC)

:'''PLEASE VOTE ON THIS at [[Wikipedia:Featured_list_candidates#Nominations]].'''  Some of the opinions expressed there are from persons who are naive in more ways than just mathematically.  If you doubt this, see the accompanying discussion page at [[Wikipedia_talk:Featured_list_candidates#Nominations]]. [[User:Michael Hardy|Michael Hardy]] 00:59, 2 Jun 2005 (UTC)

:<math>\uparrow</math>'''VOTE!'''<math>\uparrow</math>

== why are the latex images so big anyway? ==

Again: why are the latex images so big anyway? I generally have my browser text set pretty large, yet the latexs still often look rather silly. Is there some kind of preference setting to adjust the rendering size? If not, is it technically possibly for somebody to do that? [[User:Dmharvey|Dmharvey]] 17:45, 1 Jun 2005 (UTC)

: In my work browser images look same size as text, while at home the images look much bigger. I don't know the reason. It might have to do with the screen resolution besides font sizes. So we again arrive at the time-established truth that one should not use latex images mixed with text, only on a separate line. That's why, back to the question of <math>\mathbb Q</math> versus '''Q''', one should use the latter when inline. [[User:Oleg Alexandrov|Oleg Alexandrov]] 23:13, 1 Jun 2005 (UTC)

:If only the [[MathML]] mode worked... --[[User:CesarB|cesarb]] 23:32, 1 Jun 2005 (UTC)

OK, let's try something:

:<math>\int_{-\infty}^0 1\,dx</math>

Consider the integral <math>\int_{-\infty}^0 1\,dx</math> which is blah blah blah .....

(1) Look at this here equation: <math>AX^2+B=0.\,</math>  So there!

(2) Look at this here equation: ''AX''<sup>2</sup>&nbsp;+&nbsp;''B''&nbsp;=&nbsp;0.  So there!

(3) This renders all right: <math>AX^2+B=0.</math> So ereht!

:   '''No, it does not.''' It looks exactly identical to (1) above; the characters are comically gigantic. [[User:Michael Hardy|Michael Hardy]] 01:44, 2 Jun 2005 (UTC)
:: FYI For me, (1),(2) and (3) are exactly the same size, and (2) and (3) visually look identical. I have a 1600x1280 monitor so use large fonts.[[User:Linas|linas]] 03:04, 3 Jun 2005 (UTC) 

I generally use the format (2) rather than (1) for two reasons: the math notation in (1) is ridiculously too big, and it gets mis-aligned.  Possibly this could be overcome by using a different browser or altering my preferences.  I have long said that [[TeX]] looks good on Wikipedia when it is "displayed", but often looks terrible when embedded in lines of text.  Note also: 1+2 does not look as good as 1&nbsp;+&nbsp;2; ''n''&nbsp;+&nbsp;2 is better than n&nbsp;+&nbsp;2; and also better than ''n&nbsp;+&nbsp;2''. [[User:Michael Hardy|Michael Hardy]] 00:57, 2 Jun 2005 (UTC)

: Number (3) render pretty good here (but this might look horrible if you have a larger/smaller font). This is actually quite an interesting question. What if rendering of math becomes unbroken in a future version of MediaWiki? You'd rather have the stuff between <nowiki><math></math></nowiki> than marked up using html. --[[User:R.Koot|R.Koot]] 01:21, 2 Jun 2005 (UTC)

:: See the link ''Archive4(TeX)'' at the very top of this page, discussing this in as much detail as one can get. [[User:Oleg Alexandrov|Oleg Alexandrov]] 01:32, 2 Jun 2005 (UTC)

(3) looks '''exactly identical''' to (1) from my browser. [[User:Michael Hardy|Michael Hardy]] 01:43, 2 Jun 2005 (UTC)

: Hmmm.. It looks SO good over here (Firefox/SuSE 9) that I thought it was a PNG, but it isn't it's HTML

 <nowiki><span class="texhtml"><i>A</i><i>X</i><sup>2</sup> + <i>B</i> = 0.</span></nowiki>

: The problem must be with the class="texhtml"? --[[User:R.Koot|R.Koot]] 01:56, 2 Jun 2005 (UTC)

Interestingly, the font in the TeX output is smaller on Wikicities. See example at [http://wikicities.com/wiki/User:Fredrik/Tex]. Would this look better on Wikipedia? One problem is that it may be harder to read. - [[User:Fredrik|Fredrik]] | [[User talk:Fredrik|talk]] 01:49, 2 Jun 2005 (UTC)


: Looks better inline but equations are MUCH harder too read. However is you could manually select the size (with two separate tage like <nowiki><math></nowiki> and <nowiki><equation></nowiki> for example it might work? --[[User:R.Koot|R.Koot]] 02:08, 2 Jun 2005 (UTC)

::I was thinking the same thing. Also, clicking the image could show a very high resolution version in addition to the wrapped TeX code. [[User:Fredrik|Fredrik]] | [[User talk:Fredrik|talk]] 02:11, 2 Jun 2005 (UTC)

For me, the LaTeX images are slightly ''smaller'' than the surrounding text. But then, I'm using a 12pt font at 132DPI. Since most Windows boxes are at 96DPI (since a lot of Windows programs look weird if you try to change it), I can see how it can look huge. --[[User:CesarB|cesarb]] 02:23, 2 Jun 2005 (UTC)

You will never get text in images and text not in images to mesh well for everyone. Saying it should be done one way or another because "it looks better" is just nonsense. It looks better to ''you'' on ''your screen'', maybe; that says nothing about how it looks to everyone else. (BTW, I must interject at this point that the font used in the TeX images changed several months ago and I really preferred the old font!) The best solution, perhaps, would be to add a preference setting to scale LaTeX images to a (user-) specified ''relative size'' &mdash; for example, "80%" or "110%", etc. &mdash; so that each user could, if they cared, have the images scaled to match the size of the regular text in their own browser (I guess this would also have to include a ''vertical-shift'' option, as well, if that's possible to implement). The only problems I can see with this plan would be: (1) server load, since every (TeX) image would have to be tagged with ''height'' and ''width'' calculated using the user's scaling preference; and (2) readability since some browsers probably have terrible algorithms for scaling images. - [[User:Dcljr|dcljr]] <small>([[User talk:Dcljr|talk]])</small> 11:11, 2 Jun 2005 (UTC)

:For me, (2) and (3) are identical. Only (1) looks bad. I think this is because I have selected "HTML if very simple or else PNG" in my prefs - it is not determined by my choice of browser. [[User:Lupin|L]][[User talk:Lupin|upin]] 12:32, 2 Jun 2005 (UTC)

(3) is the best, because I think using images for any kind of text is not a good thing to do.--[[User:Reubot|Reubot]] 10:19, 5 Jun 2005 (UTC)

Thanks everyone for your comments and examples. I think I now understand a little better why this is such a complicated issue.

I have a question: how good is MathML at rendering ''inline'' equations (as opposed to displayed equations)? Does it handle things as well as LaTeX, like line wrapping?

[[User:Dmharvey|Dmharvey]] [[User talk:Dmharvey|Talk]] 12:56, 2 Jun 2005 (UTC)

I think the previous suggestion of a user-definable relative size attribute is quite nice. Note also that CSS (I don't know if this is true for "old style HTML attribs") allows for sizes given in "ex", e.i. the height of an "x" in the current font. maybe this could also used to fix the problem. But I also agree that (maybe unless you have a 1600x1200 screen, which is still rather exceptional - maybe wiki has statistics on screen resolution...) the images are always way too big w.r.t. the text, so a fix should definetly be provided. (Maybe also alternate style files (at worst through user prefs) could allow to cope with this issue.) [[User:MFH|<nowiki></nowiki>]]&mdash; [[User:MFH|MFH]]: [[User talk:MFH|Talk]] 22:32, 20 Jun 2005 (UTC)

== [[tangent bundle]] and [[vector field]] ==

I would really like to know your opinion on what these articles should be about. Since the tangent bundle is basically the collection of vector fields, it would be useful to make it clear what info should go where. --[[User:MarSch|MarSch]] 14:26, 2 Jun 2005 (UTC)

: These articles certainly need a lot of work. For example, the vector field article should also have a more "introduction to several variables"-level version, with explicit formulae in terms of partial derivatives etc. There should be a version of tangent bundles in terms of submanifolds of euclidean space, as well as the more abstract version there currently. [[User:Dmharvey|Dmharvey]] [[User talk:Dmharvey|Talk]] 4:52, 2 Jun 2005 (UTC)

::[[Tangent bundle]] should cover the holomorphic version, the version in algebraic geometry, too. There are also replacements ([[microbundle]]s) to consider; and mappings on tangent bundles (''not'' on vector fields - see the notorious [[push forward]] talk page discussion). Vector fields in plane regions is already an interesting area. So there seem to be reasons to have two pages. [[User:Charles Matthews|Charles Matthews]] 15:48, 2 Jun 2005 (UTC)

==[[Wikipedia:Mathematics Collaboration of the Week]]==

So what is happening there? The tag has been taken down from [[tensor]], which was current. I don't see another nomination has been made. [[User:Charles Matthews|Charles Matthews]] 16:00, 2 Jun 2005 (UTC)

== Copyright ==

I'm sorry if this is the wrong place, but I wonder if there's copyright on proofs? Can I copy some proof from my lecture notes (in my own words)? [[User:Hugo|Hugo]] 08:30, 2 Jun 2005 (UTC) (Moved from [[Wikipedia:WikiProject Mathematics/Proofs]] by [[User:Oleg Alexandrov|Oleg Alexandrov]])
:Try asking at [[Wikipedia:Village_pump]] and then summarize the answers you get; I'd like to know myself. [[User:Linas|linas]] 01:07, 3 Jun 2005 (UTC)

: (I'm not a lawyer) You will have to make a distinction between the structure of the proof and the text of the proof itself. The stucture is not copyrightable only patentable, and that is not possible because you can't patent mathematics. Whether the/a text is eligible for copyright depends on wheter or not is considered ''original''. A proof consisting mainly of formulas, "let ... denote ...", and "from which we conclude", could hardly be considered orginal (and would be very hard to prove in court). However this ''might'' change if the proof contains original/creative explanations of the proof. Note that even rewiting the text in your own words is considered plagiarism (this might again be hard to prove in court but you or other Wikipedians might (should) have some moral problems with this). The safest would likely be to ask the author of the lecture notes if you could copy part of it to Wikipedia. --[[User:R.Koot|R.Koot]] 19:11, 3 Jun 2005 (UTC)

:: I would like to mention that if some theorem is missing a proof, that might be on purpose. Some of us (if not the majority) think that  proofs should be a part of the article only if they ellucidate the article, and if they are not too hard. So, proofs for their own sake are not very encouraged. Discussion on this is under way at [[Wikipedia:WikiProject Mathematics/Proofs]]. [[User:Oleg Alexandrov|Oleg Alexandrov]] 04:18, 4 Jun 2005 (UTC)

:: R.Koot, you are mistaken, it is possible (in the US) to patent pure mathematics when the math is the embodiment of some functional procedure or algorithm.  Examples include the RSA encryption algorithm and the inversion procedures used in MRI scanners.  So while in general you can't patent a proof there may be occasional exceptions if that proof is somehow a necessary component in the description of some otherwise patentable process.  Such cases are likely to be very few and far between however.  [[User:Dragons flight|Dragons flight]] 01:15, Jun 23, 2005 (UTC)

== [[Wikipedia:How to write a Wikipedia article on Mathematics]] ==

There are some interesting discussions going on at [[Wikipedia talk:How to write a Wikipedia article on Mathematics]]. I believe as many of us should be involved in that as possible, as that article is the main document defining how math is to be written. So, comments welcome. [[User:Oleg Alexandrov|Oleg Alexandrov]] 22:25, 2 Jun 2005 (UTC)

== Conjecture for deletion ==

According to newly created [[polygon sum conjecture]] article, 

:The '''Polygon sum conjecture''' is a [[geometry|geometric]] [[conjecture]] that states that the sum of the [[interior angle]]s of a [[polygon]] are equal to 180(N-2), where N is equal to the number of sides that the polygon has.

I almost put it in [[:Category:Conjectures]], when I realized conjectures in elementary geometry do not happen that often... :) 

Anyway, see [[Wikipedia:Votes for deletion/Polygon sum conjecture]]. [[User:Oleg Alexandrov|Oleg Alexandrov]] 01:21, 3 Jun 2005 (UTC)

: Also see [[Wikipedia:Votes for deletion/Roman letters used in mathematics]] [[User:Oleg Alexandrov|Oleg Alexandrov]] 01:28, 3 Jun 2005 (UTC)

== complex multiplication and e^(pi sqrt(163)) ==

Dear all, I have added the fascinating fact concerning e^(pi sqrt(163)) to the article on [[complex multiplication]]. It doesn't really fit very well at the moment, but hopefully one day that will change. The only reason I mention this here is that I'm not sure if this formula appears anywhere else in WP, perhaps it is already stated elsewhere. Thanks peoples. [[User:Dmharvey|Dmharvey]] [[User talk:Dmharvey|Talk]] 01:32, 3 Jun 2005 (UTC)

:I've added the equation to [[Pi]], under "Numerical approximations of &#960;". [[User:Fredrik|Fredrik]] | [[User talk:Fredrik|talk]] 05:00, 6 Jun 2005 (UTC)

::There is currently an "explanation" with links to [[modular form]] and something else, which is quite frustrating because nothing is explained there. I would appreciate a more precise indication on "how", even if w/o details. [[User:MFH|<nowiki></nowiki>]]&mdash; [[User:MFH|MFH]]: [[User talk:MFH|Talk]] 12:58, 23 Jun 2005 (UTC)

:::I agree the explanation is drastically lacking in detail. I will try to do something about this at some point, but I don't promise anything soon. The problem is, to make this work sensibly would require an article on complex multiplication ''considerably'' more in-depth than the presently existing one. [[User:Dmharvey|Dmharvey]] [[User talk:Dmharvey|Talk]] 15:00, 23 Jun 2005 (UTC)

== long-term of future of mathematics in wikipedia ==
(copied from the talk page of Charles. This is an interesting discussion, and I wonder what others would like to say [[User:Oleg Alexandrov|Oleg Alexandrov]] 04:37, 3 Jun 2005 (UTC)) 

I am wondering what your opinion is of the possible long-term future of maths in wikipedia? In particular, do you think that wikipedia (or some other wiki-based medium) has the capacity to (eventually) become an authoritative source on well-understood material? I guess 'authoritative' and 'well-understood' are somewhat rubbery terms. For an arbitrary starting point, perhaps 'well-understood' might mean "material that has made it into book form by 2005", and 'authoritative' might mean that a professional mathematician might consider making WP their first port of call for learning material they are unfamiliar with. I appreciate your insight, you seem to have had a lot of experience on WP. [[User:Dmharvey|Dmharvey]] 17:21, 30 May 2005 (UTC)

:To try to sum up my take on this - mathematics is short of good survey articles, and not really short of textbooks, except for things that are quite recent. It is quite hard to get a good historical perspective, from the technical literature alone; and much harder to understand what is going on in the Russian or Japanese perspectives, than in Paris or Princeton. We ought to be trying to give a good broad coverage, by survey article standards, with reasonable references. We ought to be giving the sort of background that makes the current preprints more accessible (so, basic definitions to answer 'what the hell is X?' questions). We should reach for a good overview of the whole tradition, and what is going on globally. I don't think it is so sensible to aim to compete directly with the conference literature, say. WP ought to complement academia, and make the effort to explain 'how it all fits together' and 'why any of this matters' - which academics generally don't find the time for. [[User:Charles Matthews|Charles Matthews]] 21:01, 30 May 2005 (UTC)

::Interesting. (BTW thanks for your time in answering these questions; you must be a pretty busy guy.) I certainly agree with your last sentence, i.e. that WP should help explain 'how it all fits together', I'm very keen on that. I'm also very keen on giving historical perspective. On the other hand, it seems that WP provides an ideal vehicle for a piece of writing to start off as a survey article, but then slowly morph into something providing textbook level detail, while nevertheless remaining a survey article to a reader not concerned with details or proofs. (They just don't have to follow all the links.) Mathematics seems to be a subject area especially suited to this, since there tends to be less disagreement about correctness than in most other academic discplines.
::I'm sure this meta-wiki discussion has been had by plenty of people already :-). Perhaps I should spend some time reading what everyone else has had to say. As I am a wiki newbie, I am probably suffering from some kind of wiki-thrill, believing that WP can solve all of humanity's problems. It does seem to me to be a genuinely new form of communication/publishing media, which as you can tell I find very exciting.

WP can do some good, no question. Trying to audit quite ''how much'' progress is interesting, taxing and sometimes chastening. The first five years, for mathematics, is going to look like 10000 pages with much 'core' material. Chronologically the solid coverage can get us into the 1950s, mostly; but not past 1960. I would project, that in 2010 it would look more like 1970 rather than 1960; and even that is ambitious and would require much more expertise in the 'rarer' topics (algebraic geometry and topology, for example) than we currently command. I'm quite upbeat, but it is still very easy to find the gaps. [[User:Charles Matthews|Charles Matthews]] 10:13, 31 May 2005 (UTC)

:::Hi Charles, Dmharvey. I don't mean to butt in on this conversation, but I've enjoyed reading both of your thoughts in this and the above section (the "multiple audience" issue particularly), and I would expect others involved in [[Wikipedia:WikiProject Mathematics]] would find these discussions interesting and beneficial as well, and perhaps even want to join in ;-)  However if you prefer to keep this a private discussion, I respect that. [[User:Paul August|Paul August ]] [[User_talk:Paul August|&#9742;]] 15:13, May 31, 2005 (UTC)

As far as I'm concerned, I'm not saying anything private - go ahead, Paul. [[User:Charles Matthews|Charles Matthews]] 15:27, 31 May 2005 (UTC)

:Charles, yes, I didn't really think that what you were saying was meant to be private (I was just trying to allow for the possibility that you or Dmharvey might prefer to have a two-person conversation). And anyway there isn't anything I really want to add to the discussion &mdash; yet. I just think that you guys have been having a couple of interesting discussions that others would be interested in also. So I was trying to encourage you to consider discussing these ideas on [[Wikipedia talk:WikiProject Mathematics]]. (By the way thanks for your vote in support of my admin nomination ;- ) [[User:Paul August|Paul August ]] [[User_talk:Paul August|&#9742;]] 16:45, May 31, 2005 (UTC)

::As far as I'm concerned, nothing on WP is private :-) (Unless of course you're using [[PGP]], but that, as they say, is just not cricket.) I'm quite happy for anybody to move the above text to an appropriate venue, or to do whatever is appropriate. [[User:Dmharvey|Dmharvey]] 18:22, 31 May 2005 (UTC)

Wow, yes, agree with both Charles and Dmharvey. Realistically speaking, WP has huge gaps in just about any topic, and will need to grow at least 50-fold to fill these gaps in. It will take many many years for this to happen.  But I also agree with Dmharvey in that it seeems inevitable that WP will become the authoritative reference in a decade if not sooner; its already beyond mathworld.com in many areas.  

But please note that we will have to tackle many serious structural issues first; and if these are not solved, then it will make growth harder.  For example: Charles "survey" articles are already outnumbered by more "mundane" articles that mostly list facts.  (I myself generate "mundane" articles because I'm not knowledgable enough to write surveys in any but a few fields, and those fields bore me...).  I would like to see some system that somehow makes the survey articles more visible, more prominent.  They tend to be lost in the mire.  

I don't know how to fix this. Maybe have different classes of articles? This is kind of like the "proofs" discussion, but in reverse.  With proofs, the problem is how to hide this third-tier material so that it doesn't impede article flow. With "survey articles", the problem is how to highlight them above and beyond the rest of the bulk.

Note also the existing tension between "simple" and "advanced" treatments of the same material is going to get worse. We'll need to devise some mechanism for dealing with this, as I wonder if the current ad-hoc approach can last.  I've had Oleg delete some of my edits because they were too advanced, I've had Fropuff delete some of my edits because they were too trivial.  I'm not complaining, I'm rather trying to make note that this is a potential problem area that will recur in WP and is worthy of attention. [[User:Linas|linas]] 00:19, 4 Jun 2005 (UTC)

: Yes, the greatest problem I'm having is where to put things. I really think we need to structure all our articles hierarchically and make it clear what should go where. --[[User:MarSch|MarSch]] 10:50, 4 Jun 2005 (UTC)

In the context of Wikipedia, I think I have come to the opinion that the issues being discussed do not really raise any problems.

Suppose that we have an article X that discusses topic Y. There are lots of people who might end up looking at page X. A priori, they might be arriving there with a huge range of different levels of mathematical experiences. However, I claim that the gap between
*The lowest level of experience a person could have before they conceivably could get anything on that topic; and
*The highest level of experience a person could have and still be interested in that topic,
is actually not that large. It may ''seem'' large, but there's some kind of "logarithmic scale" operating here. I think it is possible to have a well-written introduction that can simultaneously branch off to cover many different levels of pre-experience. Obviously, not everyone will be able to write that introduction, since some people simply don't have the background to see it all in context. But, almost by definition, someone will have that context, and will (eventually) supply it. [[User:Dmharvey|Dmharvey]] [[User talk:Dmharvey|Talk]] 11:34, 4 Jun 2005 (UTC)

:Mostly agree, just please note that there are some exceptional pages: [[Torus]] and [[Laplacian operator]] are examples. Torus can run the range of middle-school "volume of a torus" to grad-school "Teichmuller space".  Laplacian runs from engineering school to harmonic analysis.  Maybe these can be treated on an ad hoc basis. Somewhere I suggested an "educational trampoline" for things like "torus", since it can be a doorway to higher math for younger students.  [[User:Linas|linas]] 17:03, 4 Jun 2005 (UTC)

::One way to deal with it is to take advantage of Wikipedia's subsection facility. The first paragraph is a corse overview, which should be understandable to the journeyman, and will probably have little valuble content for the expert. It's allright it the total novice is a *little* floored by it, because the first proper section starts on the ground floor and explains things simply. Linkouts are good, but we shouldn't expect even a novice to have to search 10 links deep in order to understand something. Following sections can build up from there. Experts who know everything can skip to the bottom, where the heavy theory lies, and the novices can stop after a section or two, when they have a good overview of the topic, but before they get into the deep math. The trick is to compromise, and cede the top of the article to the complete novices, and only put the Masters level theory at the bottom. (Summary: Novice on top, Intermediate in the middle, Expert on the bottom.) 15:35, 22 Jun 2005 (UTC)  

I would also like to mention something else about "authoritativeness" of WP. It seems to be widely acknowledged that there are issues with reliability in WP, and that this seems an insurmountable barrier to WP becoming useful to the academic community (in the present discussion, the academic mathematical community). I agree with the first half of the sentence but not the second half. Something can be useful even if it's inaccurate. And it seems that WP has a strong tendency to become more accurate over time, at least on topics that are not too sparsely covered. In the real world, no one source is enough anyway. When I want to learn about a maths topic I don't know much about, I don't just get a book out of the library. If I really want to learn something, I get at least three books or journal articles, and talk to my colleagues, asking them what their point of view is on the whole subject area, and where they think is a good place to read about it.  [[User:Dmharvey|Dmharvey]] [[User talk:Dmharvey|Talk]] 11:34, 4 Jun 2005 (UTC)

:I'm wondering if some semi-formal peer-review/voting/audit-trail type system might help with authoritativeness. I'd like to mark up a page or a portion of a page to somehow state "yea verily I have reviewed this and attest to its accuracy".  Kind of like [[wear marks]].  Have no idea how to implement this.  [[User:Linas|linas]] 17:03, 4 Jun 2005 (UTC) 

:I've sometimes wondered if a symbiosis with [http://www.planetmath.org Planet Math] might work; they'd hold peer-reviewed content, which the public cannot edit.  It could be copied from WP after some sufficient quantity of review. [[User:Linas|linas]] 21:35, 4 Jun 2005 (UTC)

:: That's why the project we have here is called [[Wikipedia:WikiProject Mathematics/PlanetMath Exchange]] (please note the word ''Exchange''; it was hoped that the map from PlanetMath to Wikipedia is invertible, and PlanetMath people could use our stuff). [[User:Oleg Alexandrov|Oleg Alexandrov]] 23:56, 4 Jun 2005 (UTC)
On the other hand, on the more general topic of "long-term future of mathematics in WP", I have some other concerns. My first concern regards typesetting. I summarise by saying that in the present situation, I don't think WP has sufficiently sophisticated typesetting for serious mathematical work. This may become a long term problem, because one important group of people we would like to attract to write articles, serious mathematicians, will be put off by something that ''visually'' looks amateurish. For those who don't believe me, I suggest trying to write a complete paper in LaTeX. It's incredible how LaTeX is able to make even completely incoherent babble look like the most brilliant piece of mathematics written since the 16th century. This might improve if browsers improve, I'm not sure.

A second concern is that there are other interesting things that a WP-like system could conceivably do, but which the current software does not support. For example, it would be lovely for WP to support a parallel development of some kind of formal proof system; i.e. symbolic manipulation software where people could enter formal proofs which are checked automatically for correctness. I don't believe such a system exists yet, except in fairly primitive forms. I think there have been a fair number of attempts, but I haven't heard of any that have scaled up well. I think in time, the collaborative nature of something like WP will solve the scaling-up problem. Then, if you believe the axioms that the system is founded on, and you believe that WP is doing its proof checking correctly, then you can be happy that the theorem you are looking at is OK. (Please don't take this paragraph too seriously; there are ENORMOUS problems, both theoretical and practical, with automated proof systems, and I just wanted to throw it up as a random thought.)

OK I've really chewed up enough bandwidth now. [[User:Dmharvey|Dmharvey]] [[User talk:Dmharvey|Talk]] 11:34, 4 Jun 2005 (UTC)

:: That's an interesting concept (mixing automated reasoning with mathematical exposition), but that's another beast entirely, in my opinion. You probably are thinking of [[Mizar system|Mizar]] or [[Isabelle theorem prover|Isabelle]]? Proofs there tend to be long and not easy for the non-expert user to construct.--[[User:CSTAR|CSTAR]] 14:59, 11 Jun 2005 (UTC)

: The proofs do tend to be longer, but the difference is getting smaller nowdays. I put a small pdf file at [http://www.skokodyn.com/strangeset/Isar_example.pdf] with an example of modern declarative formalized proof style (generated by [[Isabelle theorem prover|Isabelle]]). Having a link to a formally verified proof of a theorem certainly increases "authoritativeness". Formalized proofs of many theorems mentioned in [[Wikipedia:WikiProject Mathematics]] are accessible on the web. --[[User:Slawekk|Slawekk]] 23:49, 14 December 2005 (UTC)

== Wallpaper groups ==

Dear peoples, I have spent quite a number of hours the last few days working on [[Wallpaper group]]s. It looks almost completely different now, and I hope it is an improvement.

The only thing I plan to do with it for the next few days is finish labelling the pretty pictures. Apart from that it is in all of your capable hands.

Then I need to take a break from wikipedia, so I can do some [[Special:Randompage|other things]].

I will return in a few weeks.

[[User:Dmharvey|Dmharvey]] [[User talk:Dmharvey|Talk]] 17:09, 4 Jun 2005 (UTC)

:Wow! [[User:Paul August|Paul August ]] [[User_talk:Paul August|&#9742;]] 18:31, Jun 4, 2005 (UTC)

:: That is indeed stunning. --14:51, 11 Jun 2005 (UTC)

== banner for talk pages ==

I've just come across a nice template slapped onto talk pages of chemistry ({{tl|chemistry}}):
{| class="Talk-Notice"
|-
|align="center"|[[Image:glasswareb.gif|50px|WikiProject on Chemistry]]
|align="center"|This article is supported by the '''''[[Wikipedia:WikiProject Chemistry|WikiProject on Chemistry]]''''', which gives a central approach to '''[[Chemistry]]''' and related subjects on Wikipedia. Please participate by editing the article [[{{PAGENAME}}]], or visit the [[Wikipedia:WikiProject Chemistry|project page]] for more details on the projects.
|}
Should/do we want to have something similar? Might bring more people to the project. --[[User:MarSch|MarSch]] 18:06, 5 Jun 2005 (UTC)

:Some reaction might be nice. Any reaction. --[[User:MarSch|MarSch]] 13:24, 12 Jun 2005 (UTC)

::I didn't react since I don't have much of an opinion either way. It is quite a bit of work, and I think our current approach of inviting people personally to have a look works much better; on the other hand, it doesn't do any harm, and it will rake in some more people, so go ahead. -- [[User:Jitse Niesen|Jitse Niesen]] 20:45, 12 Jun 2005 (UTC)

Personally, I hate banners. Ditto for topic templates, and such. I suggest that you just watch a lot of pages. If you see the same person making good edits on a number of pages, invite them here.  I made hundreds of edits before I even bothered to look at this page, and am deeply suspicious of anyone who would be interested in process who hadn't been an active editor first. [[User:Linas|linas]] 04:16, 13 Jun 2005 (UTC)

== [[List of lists of mathematical topics]] ==

There is a proposal at [[Talk:List of lists of mathematical topics]] to reformat that list according to subdivisions of math. Comments welcome. [[User:Oleg Alexandrov|Oleg Alexandrov]] 19:51, 5 Jun 2005 (UTC)

== WP etiquette question ==

There has been a recent addition to [[Pythagorean theorem]] by 67.86.108.32 which although appears to be in good faith, I feel is unnecessary. I tried for a while to think of a way to rephrase it so that it would fit, but eventually decided it just shouldn't be there. What's the best thing to do in a case like that? Thanks [[User:Dmharvey|Dmharvey]] [[User talk:Dmharvey|Talk]] 11:59, 6 Jun 2005 (UTC)

Write to the talk page explaining your reasoning and why you're going to delete it.  Then [[Wikipedia:Be bold|be bold]] and delete it. Be firm but polite.  If the editor clarifies or suggests alternative wording, be reasonable. --[[User:Tony Sidaway|Tony Sidaway]]|[[User talk:Tony Sidaway|Talk]] 12:45, 6 Jun 2005 (UTC)

: OK thanks. I'll try that. [[User:Dmharvey|Dmharvey]] [[User talk:Dmharvey|Talk]] 13:02, 6 Jun 2005 (UTC)

::Try moving it somewhere else (another article), if it is information. If it's just words then delete. --[[User:MarSch|MarSch]] 14:57, 6 Jun 2005 (UTC)

::: Assuming that you have the time and find the right spot, that's a good idea. Otherwise, just moving the text to the talk page, together with your explanation for why you moved it, is perfectly fine. Deleting the text altogether, with an explanation also works. [[User:Oleg Alexandrov|Oleg Alexandrov]] 15:09, 6 Jun 2005 (UTC)

:::: One of the exasperating things about WP is suddenly to find an article changed in totally bizarre ways. It 's very very hard to be polite in these circumstances. --[[User:CSTAR|CSTAR]] 15:55, 11 Jun 2005 (UTC)

::::: It can be exasperating, but you have to expect it. There will always be new users coming into Wikipedia who will act in very unusual ways. It is just the price we pay for the open model, which has been so enormously successful. And of course politeness is always the best strategy, no matter the circumstances or the exasperation level.  [[User:Paul August|Paul August ]] [[User_talk:Paul August|&#9742;]] 16:47, Jun 11, 2005 (UTC)

== [[carmichael's theorem]] ==

Is my brain broken, or is this theorem just silly? It seems to be saying that the definition of the carmichael function is, in fact, identical to the definition of the carmichael function. Surely the theorem should instead say something like, "the recursive formula given for the carmichael function is correct, i.e. satisfies the property alluded to in [[carmichael's theorem]]"? Really these should go into the same article with a redirect on one of them. (And then one day I'll write something about larger examples of carmichael numbers, and of its relevance to primality testing, and fix up some nasty markup.) [[User:Dmharvey|Dmharvey]] [[User talk:Dmharvey|Talk]] 23:57, 6 Jun 2005 (UTC)

* Aaah. Just found [[Carmichael number]], strangely enough not linked to either of the above articles. That makes life easier. [[User:Dmharvey|Dmharvey]] [[User talk:Dmharvey|Talk]] 00:01, 7 Jun 2005 (UTC)

==The recent total re-write of [[list of lists of mathematical topics]]==

(NOT to be confused with [[list of mathematical topics]])

[[User:Samohyl Jan]] has completely re-written this '''list of lists''', with some input from me as well.

Please '''vote''' on [[list of lists of mathematical topics]] at [[Wikipedia:Featured_list_candidates#Nominations]]. [[User:Michael Hardy|Michael Hardy]] 00:23, 9 Jun 2005 (UTC)

: I'm tempted to support, but I'm not really into featured lists. --[[User:MarSch|MarSch]] 10:49, 9 Jun 2005 (UTC)

== math-wikify ==

What about a specialized wikify template for mathematics articles? This might make it easier to keep our to-do-lists recent. See also the discussion at TFD about some of these templates: [[Wikipedia:Templates_for_deletion#Template:Foo-wikify]] --[[User:MarSch|MarSch]] 10:58, 9 Jun 2005 (UTC)

:I really think this would work much better than [[Wikipedia:Pages needing attention/Mathematics]] since categories automatically keep an uptodate list of articles. If you still want to vote, you can do so at  [[Wikipedia:Categories_for_deletion#Category:Foo_articles_that_need_to_be_wikified]]. --[[User:MarSch|MarSch]] 13:23, 12 Jun 2005 (UTC)

::I am not sure about a [[:Category:Math articles that need to be wikified]], for the reasons given in the CfD discussion (everybody can wikify), but a [[:Category:Math articles needing attention]] does seem to have some use. -- [[User:Jitse Niesen|Jitse Niesen]] 20:04, 12 Jun 2005 (UTC)

== Article on VfD ==

I nominated [[topic-based vector space model]] for deletion because this is a method proposed in a paper in 2003 (see the external link in the article), so it is very new and too early to say if it is proeminent. So I think it is not yet something to be included in an encyclopedia. But I am not 100% sure. I wonder if other mathematicians would visit that article, then post their opinions on the VfD page. [[User:Oleg Alexandrov|Oleg Alexandrov]] 03:37, 10 Jun 2005 (UTC)

:I would vote "merge as a note in the VSM article and redirect". [[User:Pcb21|Pcb21|]] [[User_talk:Pcb21|Pete]] 07:45, 10 Jun 2005 (UTC)

::[[vector space model]] is by the same author... --[[User:MarSch|MarSch]] 09:39, 10 Jun 2005 (UTC)

==WikiProject logic==
Encouraged by [[User:Paul August]] on [[Talk:Aristotelian logic]], I'm posting an invitation to comment on the idea for a WikiProject for Logic.  I have a draft proposal at [[User:Chalst/WikiProject Logic proposal]], and I am interested in:
* Indications of interest
* Criticisms of the what is on the page
Many thanks in advance for your comments. --- [[User:Chalst|Charles Stewart]] 15:59, 10 Jun 2005 (UTC)

== Related articles ==

Related articles with similar content and unclear interrelations are the biggest problem I am facing. A mild version of this is the [[group]], [[group theory]] combo which can usually be sorted out, although I think this has often not happened yet, but what to think about: [[vector (spatial)]], [[vector field]], [[vector space]], [[tangent bundle]], [[tangent space]], and the also to these related [[scalar]], [[scalar field]], [[tensor]], [[tensor field]], [[Tensor_%28intrinsic_definition%29]], [[Intermediate_treatment_of_tensors]], [[Classical_treatment_of_tensors]] and maybe more. What I would like to know is which you think the possible content of these articles should be in. Possibly using templates subarticleof}} and seesubarticle}}. I would welcome any ideas. --[[User:MarSch|MarSch]] 14:00, 12 Jun 2005 (UTC)

: For now I don't have the time to take a look at all the articles; but on principle, I would think that the fact that the articles are loosely organized (with repetitions occuring in places) is a good thing as this allows for reading one article independent of the other. Also, from what I saw, [[vector (spatial)]] is a less abstract/more physical/geometrical article as compared to vector space, and integrating the two could be a mistake. In short, I am for some anarchy on Wikipedia. :) [[User:Oleg Alexandrov|Oleg Alexandrov]] 14:32, 12 Jun 2005 (UTC)

::The problem with anarchy is that it is not clear where information can be found and by extension also not clear where information should be contributed. If the efforts were a little better organized all of these articles might have already been featured, instead of the cluttered form most are now in.--[[User:MarSch|MarSch]] 15:10, 12 Jun 2005 (UTC)

Yes, well, be careful. These articles treat similar topics, but not the same topic. Vector bundles are not vector spaces; and the former links to the later in the introductory sentence. Vector bundles are a kind-of fiber bundle ... I discovered early on that attempting to make large re-organizational edits can often sink a lot of time, while failing to improve quality.  I'm surprised you're not sensing this yet ... Personally, I prefer smaller articles, with a given topic spread out across multiple articles, than trying to jam everything into one article.  As to some repetition, that's OK, too.  I'd prefer to see articles grow "organically" by accretion. After lots of accretion, they may look poor, in which case they can be restructured. However, trying to optimize content across multiple articles makes me very nervous. In particular, such a re-organization implies that you are trying to impose your world view on something that had evolved quite differently to begin with.  Catholics and Protestants are both Christians, but neither would agree to the restructuring suggested by the other. [[User:Linas|linas]] 04:02, 13 Jun 2005 (UTC)

:I agree that articles on both vector spaces and vector bundles (I didn't even mention this one) are warranted and also tangent bundle, but probably not [[vector (spatial)]], [[vector field]] and [[tangent space]]. Vector (spatial) really about vector spaces and some Euclidean metric, vector field ought to be part of vector bundle and tangent space should redirect to tangent bundle. --[[User:MarSch|MarSch]] 14:34, 13 Jun 2005 (UTC)

: I agree very much with Linas. MarSch, I think you should proceed with caution, if at all. And please consult frequently with some of us; it is good that whatever you do have the community support.

: Now, in my view, the biggest problem the math articles face is not what you mentioned above. Many articles just need careful reading, fact checking and minor fixes. One should also watch a lot for vandals, trolls, or just misguided, misplaced or poor edits. If you feel full of energy, instead of rewriting and reorganizing things, I would suggest you check more often the recent changes to the [[list of mathematical topics]] (go to that link then you will see what I mean). Janitorial work is not very glamorous, but much needed. [[User:Oleg Alexandrov|Oleg Alexandrov]] 14:17, 13 Jun 2005 (UTC)

::Janitorial work is all very nice, but it doesn't improve article. --[[User:MarSch|MarSch]] 14:34, 13 Jun 2005 (UTC)

:I agree with Linas and Oleg that most of these articles should remain separate. [[Tangent space]] and [[tangent bundle]] should remain separate for the same reasons that I mentioned on [[Talk:Cotangent space]]. [[Vector field]]s are often studied by advanced calculus and physics students long before they've every heard of things like [[manifold]]s, let alone [[vector bundle]]s. [[Vector (spatial)]] &mdash; also known as [[vector (physics)]] &mdash; is how vectors are treated in freshman physics courses (where they almost never worry about [[vector space]]s as such) &mdash; this article should definitely remain separate. I do think that the articles on tensors are rather scattered and could do with some more cohesion. However, this needs to be done carefully, with much discussion, to avoid alienating certain user groups. -- [[User:Fropuff|Fropuff]] 16:15, 13 Jun 2005 (UTC)

== [[Kettle Principle]] ==

I ran into this article, and don't know what to do about it. Any opinions? [[User:Oleg Alexandrov|Oleg Alexandrov]] 05:25, 16 Jun 2005 (UTC)

:A very bad version of the "tea making joke", probably vfd or even d --[[User:MarSch|MarSch]] 15:43, 16 Jun 2005 (UTC)

: I've heard of the joke (and there is a better version in [[Mathematician]]), but I've never heard of the "Kettle Principle" (no google hits), unless someone can come up with a reference, I would support deletion of the the page via VFD. [[User:Paul August|Paul August ]] [[User_talk:Paul August|&#9742;]] 20:31, Jun 16, 2005 (UTC)

::I first wanted to turn [[Kettle Principle]] into a redirect to [[Mathematician]], which wouldn't require listing it on VfD, but on second thought I don't even want the redirect. I don't see why it would be a candidate for speedy deletion (which of the criteria of [[WP:CSD]] applies?), so I listed it on VfD. Please vote at [[Wikipedia:Votes for deletion/Kettle Principle]]. -- [[User:Jitse Niesen|Jitse Niesen]] 23:08, 16 Jun 2005 (UTC)

== Vector space example ''x'' ==

[[Vector space example 1]] and [[Vector space example 2]] and [[Vector space example 3]] are really horrid. They are complete verbosity. Maybe we should delete them.  --[[User:MarSch|MarSch]] 15:48, 16 Jun 2005 (UTC)

:Yes, I wrote [[examples of vector spaces]] as a replacement for these pages. But they are still lingering around. I would VFD. -- [[User:Fropuff|Fropuff]] 15:54, 16 Jun 2005 (UTC)

:I would support their deletion. [[User:Paul August|Paul August ]] [[User_talk:Paul August|&#9742;]] 19:53, Jun 16, 2005 (UTC)

::All three are now listed on [[Wikipedia:Votes for deletion/Vector space example 1]]. -- [[User:Jitse Niesen|Jitse Niesen]] 23:08, 16 Jun 2005 (UTC)

== [[Pulation square]] on vfd ==

The article [[pulation square]], which in my opinion is a perfectly fine math stub, has been nominated for deletion [[Wikipedia:Votes for deletion/Pulation square|here]]. Please share your thought there. Thanks. [[User:Paul August|Paul August ]] [[User_talk:Paul August|&#9742;]] 15:30, Jun 18, 2005 (UTC)

:This is not a legit VfD. Its an act of vandalism by an extremely foul-mouthed  14-year old newcomer to WP ([[User:Big al kicks ass]]).  I reported it as such to [[Wikipedia:Vandalism in progress]].  [[User:Linas|linas]] 17:34, 18 Jun 2005 (UTC)

==[[:Category:Physics]]: general/basic/introductory concepts==
We're currently having a brain storm on [[Category_talk:Physics]] about the following questions:
* How best to distinguish the articles that genuinely cover general topics from those that have been moved into the main physics category recently and jsut aren't specified yet. 
* What to call a category for mathematical tools, such as tensors, and if this makes sense at all.
You're cordially invited. &mdash; [[User:SebastianHelm|Sebastian]] [[User_talk:SebastianHelm|(talk)]] 07:50, 2005 Jun 20 (UTC)

==[[Democratic peace theory]]==

An excessively original believer in this piece of social science questions the following observation, which seems trivial to me: 

(... The proper odds to judge a set of data which satisfies a theory deriving its parameters from that [identical] data is the chance that the data would satisfy the theory using, not those particular parameters, but any possible parameters.)

If one of you can think of an exact source, [[Talk user:Pmanderson|contact me]] or comment on the article's  [[Talk:Democratic Peace Theory|talk page]]. Now at bottom. [[user:Pmanderson]]

: With due respect to the person who actually wrote the quote above, it seems to me of little value and poorly phrased. [[User:Oleg Alexandrov|Oleg Alexandrov]] 16:13, 21 Jun 2005 (UTC)

::Amateurishly phrased, and trivial; but apparently not allowed for by the political scientists in their calculations, and denied by [[User:Ultramarine]]. [[User:Pmanderson|Septentrionalis]] 17:27, 21 Jun 2005 (UTC)

: I think this is highly non-trivial, even ignoring the fact that the GUT is supposed to have no parameter freedom. It does not mention by what probabillity distribution that chance is to be calculated. By incorporating that distibution into your theory you can fix the outcome of the judgement to probably a very great extent. Thus I think the statement is highly ambiguous or even non-sensical. Also why does it say "judge a set of data"? Surely the theory is what you want to judge. Theories are judged by their predictions, their intuitive explanatory power and Ockham's razor. --[[User:MarSch|MarSch]] 09:51, 22 Jun 2005 (UTC)

:Thank you. I think the following phrasing is what I mean: see if you can object to the following:

::''Using a set of data to determine the parameters of a theory, and then validating the theory by applying it to the ''same'' set of data is a weak form of proof. Normal statistical tests assume the theory is independent of the data.'' [[User:Pmanderson|Septentrionalis]] 16:13, 22 Jun 2005 (UTC)

:::I'll object. I know very little about statistics, but it was my impression that this is exactly how statistics is done. When a medical trial tests the effectiveness of drugs, they don't try to fit parameters to some of the data, and then try to validate with another chunk of the data. They try to fit ''all'' of the data; they validate the theory by looking at the standard deviation and the correlation. So its not a weak proof at all, its the standard way by which statistics is done. I thought [[User: Michael Hardy]] was into statistics.  [[User:Linas|linas]] 00:42, 23 Jun 2005 (UTC)

::::medical tests just try to find out which out of a few treatments works best. There is no parameter fitting and hardly any theory, just facts that have been measured.--[[User:MarSch|MarSch]] 10:39, 23 Jun 2005 (UTC)

So far I'm still finding this very vaguely expressed.  I'm not sure what [[User:Pmanderson|Septentrionalis]] a.k.a. [[user:Pmanderson]], is trying to say. [[User:Michael Hardy|Michael Hardy]] 01:48, 23 Jun 2005 (UTC)

:The context is in [http://en.wikipedia.org/w/index.php?title=Democratic_peace_theory&oldid=15648163 this version]; the section called '''Significance'''. Rummel, a political scientist, is trying to prove a statement about all "sufficiently nice" democracies: to wit, that they don't go to war with each other. He narrows his sample of democracies by excluding those states with less than a certain proportion of voters, and less than a certain age. These are [[parameter]]s, in the real sense of the word.
:It is possible that he chose his values parameters '''precisely''' to get as many democracies, and as few wars, as possible. Let us suppose this true. If so, he is then testing the resulting theory against the historical record for the same period. I believe that this is a weaker test than if he had chosen his parameters ''a priori'' and then looked at the historical record. 
:This seems to me actually a fairly trivial observation, but it is the one that was challenged. (And my statistics may be rusty; I was  an actuary some years ago, after all.) [[User:Pmanderson|Septentrionalis]] 02:41, 23 Jun 2005 (UTC) -and after previewing I see the error of agreement in the paragraph. 
<sigh>

Allright, let me say some things. I think what we are talking about here is not a theory at all, since it has no predictive power, but just a statement of fact. The fact that if you define liberal democracy so and so, then there is so and so much war. If you define it somewhat differently you may get a different picture. For an informed picture you should present a few of these statements ranging from a restrictive to a broad def. If you don't like that picture then you can leave out some data (a few statements) thereby deceiving people into thinking what you want them (and possibly yourself also) to think. This you might call fitting the parameters. Looking at a single set of parameters is surely better than this, but also leaves much to be desired, as I explained.--[[User:MarSch|MarSch]] 10:56, 23 Jun 2005 (UTC)

:OK, I understand now. What Rummel should have done is to graph number of wars as a function of parameters (voting age, population size, etc.). ''If'' he finds that the graph is flat (i.e. independent of the parameter) then he has a theory. If there is a strong correlation between the parameter and the number of wars, then he has no theory until he explains ''why'' there is a strong correlation.  So maybe there is indeed an error of methodology. Either that, or a misinterpretation of Rummel's work. [[User:Linas|linas]] 15:44, 23 Jun 2005 (UTC)

:I mostly agree with the ''Significance'' section. If you only have one set of data and you have to first deduce a theory, you normally ''randomly'' split the data set. The first part is used to find a theory, including the parameters, and the second part is used to verify the theory. 

:I think it's a valid theory and might be true, but so far it's not proven, there is a deep flaw in the statistical argument. ''Future'' will show if the theory is right. [[User:Markus Schmaus|Markus Schmaus]] 18:35, 23 Jun 2005 (UTC)

== [[Morton's theorem]] ==

I ran into this article today. From what I see, this article is the thoughts of a certain [[Andy Morton]] about [[poker]] posted on rec.gambling.poker ([[Usenet]]) around 1997. It seems that his post was rather word for word pasted in this article, and that this article is not encyclopedic. How about voting it for deletion? [[User:Oleg Alexandrov|Oleg Alexandrov]] 19:53, 25 Jun 2005 (UTC)

:My first impression is not that it should be deleted. However, it may be a copyright issue, so I asked the user who posted it if this could be clarified, see [[User talk:Fekko]]. If I do not receive an answer, I will list it on [[WP:CP]]. You may also want to confer with [[User:Revolver]], who is apparently responsible for our article on the [[Fundamental theorem of poker]]. -- [[User:Jitse Niesen|Jitse Niesen]] ([[User talk:Jitse Niesen|talk]]) 20:56, 25 Jun 2005 (UTC)

::First of all, although it's math-related, it's not really a "theorem", so I deleted it from that category. One thing that's not made clear, is that the first paragraph appears to me to be Caro's words. This makes a big difference in reading the post. But, it is definitely a legitimate concept, in fact, it may be one of the most important concepts in all of poker. I'll try to summarise the gist of the post, esp. the example, so as to minimise the potential copyright problems. But, it's definitely encyclopedic. [[User:Revolver|Revolver]] 13:20, 26 Jun 2005 (UTC)

== [[Birthday distribution]] ==

Here's another article on which input is needed. Probabilists out there, do you think this is rescuable? So far, it looks like a table of data obtained by using a paper from 1981. [[User:Oleg Alexandrov|Oleg Alexandrov]] 20:13, 25 Jun 2005 (UTC)

:This is a copy of http://www.mathcad.com/library/LibraryContent/puzzles/soln28/exact28.html, but I doubt that it is copyright-able as it's basically a table of numbers. However, I don't see much encyclopaedic value in it. -- [[User:Jitse Niesen|Jitse Niesen]] ([[User talk:Jitse Niesen|talk]]) 21:04, 25 Jun 2005 (UTC)

== Proof of... articles ==
Any objections to moving [[Proof of Leibniz formula]] to [[Leibniz formula]] and [[Proof of Viète formula]] to [[Viète formula]]? I moved [[Proof of Wallis product]] earlier, but didn't notice these two. Are there any other ''proof of X'' articles without a main ''X'' article that should be handled similarly? - [[User:Fredrik|Fredrik]] | [[User talk:Fredrik|talk]] 21:22, 25 Jun 2005 (UTC)

:Actually, it seems that [[Leibniz formula]] should more properly be a disambiguation page... - [[User:Fredrik|Fredrik]] | [[User talk:Fredrik|talk]] 21:22, 25 Jun 2005 (UTC)

::No objections. --[[User:MarSch|MarSch]] 10:22, 26 Jun 2005 (UTC)

== [[Hyper generalized orthogonal Lie algebra]] ==

A badly written article should not be deleted, rather cleaned up. That is the conventional wisdom, but this particular article is trying my patience. Could anyboyd knowing this stuff take a look and say if this at all makes sence? Thanks. [[User:Oleg Alexandrov|Oleg Alexandrov]] 22:07, 25 Jun 2005 (UTC)

:The mathematics is probably OK. It's about explicit expressions of things like the Lie algebra of the Poincaré group, which is a semidirect product, in a [[block matrix]] way. Which is perfectly sensible. There is some odd language, but it is really mostly about writing things down in a 'dimensionless' way (c=1, that sort of thing). I wouldn't vouch for the title being standard. [[User:Charles Matthews|Charles Matthews]] 22:27, 25 Jun 2005 (UTC)

== italic "i"s for the imaginary unit are being changed to non-italic, please comment ==

[[User:Wurzel|Wurzel]] is proposing [[Talk:Complex number#The non-italic writing style of the imaginary unit|here]] that the [[imaginary unit]] be represented using a non-italic i, and has been changing articles accordingly. The first seven books I've just pulled from off my shelves, all use an italic i. Please share your thoughts on the appropriate talk page(s). [[User:Paul August|Paul August ]] [[User_talk:Paul August|&#9742;]] 17:04, Jun 26, 2005 (UTC)

== scope of [[derivative]] article ==

There's an interesting discussion going on at [[Talk:Derivative]] concerning the scope/audience of the article. I'd be interested if anyone supports what I have to say. Alternatively, if you disagree with me, please add your voice. When I hear enough I'll shut up :-) [[User:Dmharvey|Dmharvey]] [[User talk:Dmharvey|Talk]] 00:25, 27 Jun 2005 (UTC)

: The discussion in question is at the ==Scope of derivative article== heading and below it. Comments are very welcome (requested), since the issue of what to expect from the audience reading our articles is (I think) one of the more pressing ones this project faces. [[User:Oleg Alexandrov|Oleg Alexandrov]] 03:06, 27 Jun 2005 (UTC)

== Relaunch of Mathematics COTW ==

For those who don't know, the [[Wikipedia:Mathematics_Collaboration_of_the_Week|Mathematics Collaboration of the Week]] has been re-launched. Please nominate and vote for articles to focus on each fortnight. Both stubs and articles that are not stubs, but are confusing or poorly written, are acceptable. [[User:NatusRoma|NatusRoma]] 29 June 2005 05:42 (UTC)

==Please vote!==

Please vote at [[Wikipedia:Featured picture candidates/Ford.circles.gif]].  The selection criterion includes the following:

::the images featured on Wikipedia:Featured pictures should illustrate a Wikipedia article in such a way as to add significantly to that article

and stated that merely being a spectacular picture is not a sufficient qualification.  This picture will probably not be considered spectacular; it's very simple.  But it can make clear to ordinary laypersons the concept explained in [[Ford circle]] that would otherwise probably be understood by few other than mathematicians.  <hubris> Thus in "illustrat[ing] an ... article in such a way as to add significantly to that article" I think it excels. </hubris> [[User:Michael Hardy|Michael Hardy]] 30 June 2005 23:10 (UTC)

== Renaming the [[derivative]] article ==

There is a proposal at [[Talk:Derivative#move to differentiable function]] to move that article to [[Derivative (high school version)]] or some other similar sounding title. The reason seems to be that the [[derivative]] article as now written is not representative about what derivative is in mathematics, rather, it focusses on the most elementary calculus definition. Comments welcome. [[User:Oleg Alexandrov|Oleg Alexandrov]] 1 July 2005 02:20 (UTC)

:Don't say ''derivative (high school version)''; say ''derivative (elementary calculus)'', or something like that. [[User:Michael Hardy|Michael Hardy]] 5 July 2005 01:02 (UTC)

== [[The ugly theorem]] ==

I found this article about a rather elementary fact in [[number theory]]. Anybody heard it called that way? Google yields nothing about this particular theorem. [[User:Oleg Alexandrov|Oleg Alexandrov]] 1 July 2005 03:04 (UTC)

I don't understand what the "theorem" or elementary fact aspect is.  It just looks like a property possessed by three particular numbers.  Can anyone elaborate? (Google no help to me either) [[User:Kinser|Kinser]] 1 July 2005 03:50 (UTC)

:Checking the [http://en.wikipedia.org/w/index.php?title=The_ugly_theorem&action=history page history], it looks like an anonymous user with a tenuous grasp of English just typed up some info about something they found in a book or online, which then got copyedited into the current version by other people. The original version of the article didn't actually claim that Masahiko Fujiwara '''named''' the result ''the ugly theorem'', though it does suggest that the "theorem" is that only the given three numbers have this property. In the absence of any other information about it, I would be inclined to [[WP:VFD|delete]] the article on the grounds that the information has not been able to be verified. - [[User:Dcljr|dcljr]] <small>([[User talk:Dcljr|talk]])</small> 1 July 2005 05:13 (UTC)

::I cannot verify it. Let's get it deleted. --[[User:MarSch|MarSch]] 1 July 2005 11:43 (UTC)

== Errors in articles ==
I don't know if this is the right place to comment on this; please move if you know a better place.

About 3 months ago, I added an intentional error to the page about "Distribution", date/time "21:33, 31 March 2005 82.157.131.133 (→Formal definition)". Of course the type of convergence is weak, not strong. Jitse Niesen was so kind to move the error part in the text, and has been unnoticed until now.

If such a major error in a basic mathematical article can survive this long, how much errors will there be in the more advanced subjects? For me this is enough proof not to trust Wikipedia articles. [[User:Hugo|Hugo]] 1 July 2005 11:37 (UTC)

:you shouldn't trust anything that you've not seen the proof of. --[[User:MarSch|MarSch]] 1 July 2005 11:46 (UTC)
::I don't trust your statement. I even don't trust my own statements. With such an argument there is no need to make a precise encyclopedia. I was in doubt about adding a statement like "Don't just say you can never trust your sources" but I hoped such a non-argument wouldn't be said. [[User:Hugo|Hugo]] 1 July 2005 12:01 (UTC)
:::How's this for a non-argument: If you're intentionally introducing errors into articles, why should anyone engage you in serious discussion? In any case, see [[Wikipedia:Replies to common objections]]. - [[User:Dcljr|dcljr]] <small>([[User talk:Dcljr|talk]])</small> 2 July 2005 01:39 (UTC)

:::: There is sad truth in what [[User:Hugo|Hugo]] is saying above. But this is not surprising. There are 7000-8000 math and math-related articles on Wikipedia (7995 items on the [[list of mathematical topics]] as of now). There is not enough time and man power to check all contributions for mathematical correctness. There is not enough manpower even for style fixes. Besides, I am sure that a good chuck of those articles represent "dark matter", articles which are not on the watchlist of any active Wikipedians. One of course can check the changes to them from the [[list of mathematical topics]], but again, who has the time? So, while Wikipedia can be lots of fun for editors (me at least :) and a useful source for readers, ultimately it is not much more reliable than a lot of other information on the internet. And there is not much to be done about this. [[User:Oleg Alexandrov|Oleg Alexandrov]] 2 July 2005 02:21 (UTC)

:There are lots of errors in wikipedia articles, we just corrected a subtle error in [[linear independence]], but as a survey showed, many textbooks contained the same error. I found wikipedia very helpfull in several cases, but you're free to trust or not to trust any source you want to. [[User:Markus Schmaus|Markus Schmaus]] 2 July 2005 03:18 (UTC)

Perhaps you might be polite enough to fix the error, now that it has been spotted, and now that the point has been made  :-) (Although I see that there would be additional mileage gained by ''not'' fixing the error, since then you could point out that the error has not been fixed even after explicitly pointing it out in a discussion forum like this....)

But seriously... I agree that this is a problem, but probably not as big of a problem as you are making it out to be. You said: "For me this is enough proof not to trust Wikipedia articles." I agree: you ''shouldn't'' trust wikipedia articles. That should have been clear from the first moment you heard of the concept of wikipedia. And I don't think it is at all a non-argument to say "don't trust your sources". I genuinely believe in that argument. Trust is not black and white. It is possible to have a spectrum of trust in things you read, and a lot of it depends who wrote it and what your opinion is of them.

You also said: "With such an argument there is no need to make a precise encyclopedia." In my opinion, this is a vacuous statement; it is ''impossible'' to make a precise encyclopaedia. Precision is an ideal; I think generally wikipedians strive towards it, and they do a reasonable job, but I'm under no illusions of it being completely attained. However, it is possible to make a ''useful'' encyclopedia. And I think wikipedia is already such an object, and becomes more useful every day. An article can still be useful, even if it contains errors. (And I think most articles do not contain ''deliberate'' errors &ndash; the most insidious kind). For this reason, I still welcome your contributions, as long as the bulk of them are useful :-) [[User:Dmharvey|Dmharvey]] [[User talk:Dmharvey|Talk]] 2 July 2005 12:48 (UTC)
:I sometimes wonder what percentage of Wikipedia's inaccuracies are there because someone felt the need to make this point. [[User:Isomorphic|Isomorphic]] 2 July 2005 19:00 (UTC)

::I concur with the above posts: I trust Wikipedia generally far less than textbooks or mathematical papers (which does not mean that they are perfect), not only because of the anonymous edits but also because most articles are not written by experts and most are not reviewed by experts. Furthermore, I personally am more careful when writing a mathematical paper than when editing the Wikipedia, and I guess this is true for most of us. It is highly unfortunate that Hugo mentions a weakness on which most of us agree without offering any suggestion for overcoming this weakness, and also that he hasn't tried yet to amend the error he deliberately introduced. For reference, this is all about the following sequence:
:::"The space D'(''U'') is turned into a [[locally convex]] topological vector space by defining that the sequence (''S''<sub>''k''</sub>) converges towards 0 if and only if ''S''<sub>''k''</sub>(&phi;) &rarr; 0 for all test functions &phi;; this topology is called the [[strong operator topology|strong (operator) topology]]."
::Here, D'(''U'') is the (continuous) dual of the space of test functions. The topology is certainly not the strong operator topology because the space D'(''U'') does not consists of operators. Hugo seems to claim that it's the weak topology, but my impression is that it's the weak* topology. Can he (or anybody else) explain this? -- [[User:Jitse Niesen|Jitse Niesen]] ([[User talk:Jitse Niesen|talk]]) 2 July 2005 20:09 (UTC)

Lets get real. It appears that [[User:Hugo]] doesn't understand the process by which mathematics is actually done, and how research is published, much less how WP articles are written and corrected. A WP article can only be corrected when someone who is knowledgable and interested in a topic spots an error and corrects it. The error was presumably not corrected because there were no readers who were capable and interested in pursuing the particular claim. There's two ways to spot the error: one way is to be extremely knowledgable on the topic, and spot it instantly when the vandalism occurs. Clearly, there is no such person watching this article.  The other way is for someone who is weak on the topic, but is interested in it, to be engaged in the processes of performing research, to eventually notice the error. Seems that was not the case, either.  There is a third class of readers; those who didn't notice and didn't care.  I think the above analysis shows that what Hugo really discovered is something about the quantity and type of readers of WP math articles, and not about the quality of the articles themselves.

If [[User:Hugo]] was actually performing research, and actually using WP as a source, then if there were errors in the articles that Hugo was reading, he would have eventually found them. I presume that he'd eventually find them, since I presume he double- and triple-checks his work.  If not, and he publishes his work with errors and erroneous conclusions, then he is a fool, and has only himself to blame and not WP.  

Ethical norms are such that anyone who is intentionally misleading, such as Hugo was, has crossed an ethical boundary, going in the wrong direction.  Equally, if someone was deceived by his deceptions, they can blame Hugo. But, on the other hand, if WP contains honest mistakes (which it does), and someone is lead astray by these errors, then they are unfortunate or dumb or both.  Hugo has only demonstrated that one can fool some of the people some of the time; this is hardly new.

If Hugo is interested in refereed math referneces, he should perhaps engage in thinking a bit about the WP and PlanetMath Exchange. We've talked about this here, before.

Everyone who has done research has found errors in published articles and books; some minor, some major.  Errors on WP have the opportunity to be corrected, those on the printed page do not. Take a look a look at [[Talk:Bessel function]] for a real-world example of an error in a famous and highly-respected book that failed to propagate into WP. We actually have a chance to do better.  [[User:Linas|linas]] 3 July 2005 00:04 (UTC)

: Linas: well said. [[User:Dmharvey|Dmharvey]] [[User talk:Dmharvey|Talk]] 3 July 2005 01:04 (UTC)

== graphs ==

[[Image:Weighting curves.png|300px|right]]

I've been teaching myself how to make pretty graphs in gnuplot and maxima.  Is there a guide to this somewhere?  If not, there should be.  I will gladly contribute what I have learned today and yesterday.  See [[commons:Image:Weighting curves.png]] and [[commons:Image:Hilbert_transform.png]] for examples. - July 2, 2005 17:48 (UTC)

:A guide would be wonderful. I also hope MediaWiki gets support for gnuplot integration some day. [[User:Fredrik|Fredrik]] | [[User talk:Fredrik|talk]] 2 July 2005 20:17 (UTC)

::Such a guide would certainly be very useful, so please start it. I had so many problems getting nice graphs with gnuplot that I reluctantly switched to Matlab (see [[:Commons:Image:Schwarz-Christoffel transformation.png]] for my latest contribution), but judging from your graph to the right, gnuplot can also make nice pictures. -- [[User:Jitse Niesen|Jitse Niesen]] ([[User talk:Jitse Niesen|talk]]) 2 July 2005 22:07 (UTC)

A guide would be great; but don't make it into a guide for gnuplot, make it rather a set of "suggested" line weights, styles, etc. for WP, and how to set those things.  I note that the above graph looks very nice, whereas the gnuplot default settings look quite poor on WP. [[User:Linas|linas]] 2 July 2005 23:12 (UTC)

We have been trying to standardize plots for [[probability distributions]]. A summary of the latest definition of a "standardized plot" is at [[Template talk:probability distribution#Standard Plots]]. See [[normal distribution]] for an example. A basic trick is to make the plot very large, like 6000 pixels on a side, using size 48-64 font size and 17 pixel line thickness, then reduce down to about 1000 pixels on a side using bicubic interpolation. This give a plot with no jagged lines. It is, however, big enough so that someone could download it and use it for projection purposes without pixellation. The display size for the plot is about 325 pixels for the Wikipedia article. Plots are as language free as possible, and uploaded to Wikimedia commons, so that they may be used in any language version of Wikipedia. [[User:PAR|PAR]] 3 July 2005 00:01 (UTC)

:Any way to do the Gaussian blurring and bicubic interpolation without using PhotoShop? Can GIMP or Matlab do this? -- [[User:Jitse Niesen|Jitse Niesen]] ([[User talk:Jitse Niesen|talk]]) 3 July 2005 03:03 (UTC)

:Aha!  Those graphs look really great, and I based mine off of one without realizing they were standardized.  Also instructions from [[User:MarkSweep|MarkSweep]].  The two I linked to above have instructions in the commons page for reproducing them.  One is in gnuplot and the other is in Maxima.  I used GIMP to do the blurring and resizing.  I wonder if there's a way to get gnuplot to generate the graph the way we want directly to PNG? - [[User:Omegatron|Omegatron]] July 3, 2005 03:25 (UTC)

:I did a quick write-up at [[Wikipedia:How to write a Wikipedia article on Mathematics#Graphs]]. It would be great if somebody added the specific commands to do this in gnuplot, matlab, gimp, photoshop, and other programs. -- [[User:Jitse Niesen|Jitse Niesen]] ([[User talk:Jitse Niesen|talk]]) 4 July 2005 14:42 (UTC)

:: Something about graphs (very shortly) is mentioned in another paragraph in [[Wikipedia:How to write a Wikipedia article on Mathematics]] (up several sections). Do you think that part and what you wrote could (should) be merged? Or otherwise, the short part above could mention that more detail is below? I don't know myself how to proceed. [[User:Oleg Alexandrov|Oleg Alexandrov]] 4 July 2005 15:31 (UTC)

:::I don't see the two sections.  Were they already merged?  I will add the instructions for gnuplot and maxima (which outputs to gnuplot) later today.  Or you can do it.  I included it in the linked images.  Too busy right now. - [[User:Omegatron|Omegatron]] July 5, 2005 14:57 (UTC)

::::The first section is just two sentences in "Main part" (1.2 if you have numbering turned on), starting with "A picture is a great way of bringing a point home". I had already added a reference to the Graph section. -- [[User:Jitse Niesen|Jitse Niesen]] ([[User talk:Jitse Niesen|talk]]) 5 July 2005 15:26 (UTC)

==Dotted framebox around formulas==
What do people think of framing important formulas as in this example encountered at [[differintegral]]

<div style="margin-left:1em;margin-right:1.em;padding: 1em; border: 2px dotted blue;"><div style='float:right'>'''''definition'''''</div><math>{}_a\mathbb{D}^q_tf(t)=\frac{d^qf(t)}{d(t-a)^q}</math>
<br><math>=\frac{1}{\Gamma(n-q)} \frac{d^n}{dt^n} \int_{a}^{t}(t-\tau)^{n-q-1}f(\tau)d\tau</math></div>

I myself find it not very pleasing. [[User:Oleg Alexandrov|Oleg Alexandrov]] 3 July 2005 01:09 (UTC)

::*The template {{tl|ImportantLabeledEquation}} has been put up for deletion on [[WP:TFD]]. I've subst'ed the template here for readability, and so that it will be preserved in case of deletion. --[[User:Quuxplusone|Quuxplusone]] 23:17, 28 July 2005 (UTC)

No I can't say I like it much either. [[User:Paul August|Paul August]] [[User_talk:Paul August|&#9742;]] July 3, 2005 03:51 (UTC)

Not a fan.  Doesn't look especially nice, plus it adds extra formatting, which I consider a Bad Thing unless absolutely necessary. [[User:Isomorphic|Isomorphic]] 3 July 2005 06:18 (UTC)

I don't care for that particular example either.  But as it happens, I have been mulling over introducing '''equationbox''' templates for my project of improving the [[General relativity]] articles.  See the talk page for [[exact solutions of Einstein's field equations]].  I would be grateful if anyone has any ideas.  Also, I just used a table in the section on ''Lie algebra of the Lorentz group'' in my new revision of the article on the [[Lorentz group]].  I think the information there is useful in an encyclopedic way, but it would be nice if the table could be shrunk a bit.  This problem exhibits the problem I am having in devising equationbox templates; existing infoboxes display some kinds of data in a generally vertically stacked way, but for equations one typically needs a more horizontal array which someone avoids interrupting the main flow of text.  Maybe my notion is too quioxitic to be worth pursuing, but if you have any ideas, please add them to the above cited talk page.  TIA---[[User:Hillman|CH ]] [[User_talk:Hillman|(talk)]] 3 July 2005 06:27 (UTC)

:I don't really like this particular example. Keeping an open mind for other examples. Also I don't like the definition text in the corner. If you want to define something you should use := or =: for absolute clarity. --[[User:MarSch|MarSch]] 3 July 2005 13:25 (UTC)

== [[Paul Erdős]] moved to [[Pál Erdős]] ==

What do people think about the recent move of [[Paul Erdős]] to [[Pál Erdős]]? [[User:Paul August|Paul August]] [[User_talk:Paul August|&#9742;]] July 3, 2005 04:14 (UTC)
:In general, articles should be at the title most commonly used ''in English''.  See [[Wikipedia:Naming conventions (common names)]].  The new title may be more "correct" in some sense, but it's not what most books have.  Until "Pál Erdős" becomes the generally used form, I would rather stick with "Paul". [[User:Isomorphic|Isomorphic]] 3 July 2005 06:15 (UTC)

:I agree with Isomorphic, although I do think the English-language article should mention the Hungarian form of his name.---[[User:Hillman|CH ]] [[User_talk:Hillman|(talk)]] 3 July 2005 06:29 (UTC)
::I've put a mention of the Hungarian form in the intro, and moved the article back to its original title. [[User:Isomorphic|Isomorphic]] 3 July 2005 06:32 (UTC)

I can understand why Russian names are not at their original name, although they probably shold be, but I cannot understand this at all. What's worng with Pál? --[[User:MarSch|MarSch]] 3 July 2005 13:37 (UTC)

:See Isomorphic's response: the problem with Pál is that it is not used that often in English. -- [[User:Jitse Niesen|Jitse Niesen]] ([[User talk:Jitse Niesen|talk]]) 3 July 2005 14:58 (UTC)
:: I think the English name should be used. That's how I always encountered this guy in the English mathbooks. Same thing as with [[John von Neumann]] who orignally was Janos. [[User:Oleg Alexandrov|Oleg Alexandrov]] 3 July 2005 15:38 (UTC)

Anyone who publishes scientific articles is urged to choose one name, and one name only, under which to publish, so as not to confuse readers and in order to make bibliographies easier to assemble. Under what name did Paul Erdos publish? Shouldn't the article be under the name he himself chose? -- [[User:Linas|linas]] 3 July 2005 15:46 (UTC)

:I didn't even know John von Neumann is actually named Janos. How stupid is that. Or did he change his name upon becoming an American? --[[User:MarSch|MarSch]] 3 July 2005 16:09 (UTC)

I took a quick search on [[MathSciNet]]. Everywhere I saw Paul. The only exception is
: Surányi, J. Remembering Pál Erdös.  Paul Erdös and his mathematics, I (Budapest, 1999),  47--49, Bolyai Soc. Math. Stud., 11, János Bolyai Math. Soc., Budapest, 2002. 01A70.
So, even the Hungarians call him Pál only to emphasize that he is their guy, while the formal name is Paul. [[User:Oleg Alexandrov|Oleg Alexandrov]] 3 July 2005 16:17 (UTC)

:Why do I prefer Isomorphic's criterion to Linas's criterion? I think biographies in en:wiki should be named according to the name English language readers are most likely to encounter, particularly in searching on the web.  Usually, this will agree with the name the person went by in his own writings (such is the case with Paul Erdos), but there are exceptions, such as some Russian mathematicans whose names appeared in print in various German and French language journals with transliterations which would now be regarded as archaic, like Tschebycheff.  So an article on '''Chebyshev''' should use the currently most popular spelling in English language sources, but should of course mention other forms of the name which a reader might encounter.  Any questionable cases should probably be resolved by asking what choice of name is least likely to confuse the average Wikipedia reader.  So for example, some modern transliterations of Chinese names or Russian names might actually be more confusing than using the most commonly encountered name.  Case in point: you all probably know who Shing-Shen Chern was (if not see [http://cms.zju.edu.cn/shuxueyushuxueren/En/chernbook.htm]), but the wiki biography is called [[Shiing-Shen Chern]].  I am told this is a more accurate transliteration, but it is neither what he most often went by nor the form of the name which English language readers are most likely to encounter in web searches.---[[User:Hillman|CH ]] [[User_talk:Hillman|(talk)]] 3 July 2005 20:26 (UTC)

:P.S. An example of another common naming problem: [[Charles Émile Picard|Émile Picard]] went by ''Émile'', not ''Charles'', but his biography appears under his full name, which readers are unlikely to encounter except at the popular MacTutor Archive [http://www-groups.dcs.st-and.ac.uk/~history/], which uses full names exclusively.  This practice always makes me think of the quip that triple barrelled names always seem to denote either murderers (Lee Harvey Oswald) or philosophers (John Stuart Mill). ---[[User:Hillman|CH ]] [[User_talk:Hillman|(talk)]] 3 July 2005 20:45 (UTC)

==Maths COTW: Manifold==

As mentioned above, we are witnessing an attempt to revive the [[Wikipedia:Mathematics Collaboration of the Week|Mathematics Collaboration of the Week]] (which should probably be renamed to ''Collaboration of the Fortnight'' since it seems to run over two week periods). I am pleased that [[manifold]] was chosen to be the target of the collaboration and I'd like to invite all of you to contribute to this article. Note that we are currently rewriting the article at [[manifold/rewrite]]. Please put further comments on [[Talk:manifold/rewrite]]. -- [[User:Jitse Niesen|Jitse Niesen]] ([[User talk:Jitse Niesen|talk]]) 4 July 2005 13:26 (UTC)

== Hierarchy in the math articles ==

What people think of the article [[tangent bundle]] having on top the notice that it is a subarticle of [[differentiable manifold]]? Or of the planned [[topological manifold]] article being thought as a subarticle of the [[manifold]] article? I find this terminology introduced by MarSch a bit unusual. It implies that some articles are subordinate to others. 

Also, I am not a native speaker of English, but doesn't the phrase
:''[[Tangent bundle]] is a subarticle of [[differentiable manifold]]''
imply the former is a chunck of text contained in the latter, rather than a standalone article is it is now? [[User:Oleg Alexandrov|Oleg Alexandrov]] 4 July 2005 15:43 (UTC)

:I am not a big fan of the hierarchy thing. It is only in very rare cases that I would approve. This is not one of them. I bet that the term "tangent bundle" is probably used in other areas of mathematics that have nothing to do with differentiable manifolds, or at least are only loosely analogous to them. I think algebraic geometry might be an example, but I'm not an expert. Perhaps someone else can expand on this. (Oleg: I'm not even sure if "subarticle" is a real english word :-) [[User:Dmharvey|Dmharvey]] [[User talk:Dmharvey|Talk]] 4 July 2005 20:06 (UTC)

With few exceptions, no article should be subordinate to any other article. I can imagine some kind of "subarticle of" relationship perhaps being useful, but I don't think it should be a hierarchical parent-child relationship. We would certainly want an article to possibly be a "subarticle of" more than one article, and perhaps even two articles to be "subarticles of" each other, both of which however run counter to the usual notion of "subness". In short I don't think it is probably a very good idea. [[User:Paul August|Paul August]] [[User_talk:Paul August|&#9742;]] July 4, 2005 21:06 (UTC)

::The terminology is indeed confusing, but I like the idea of having a prominent link at the top of [[tangent bundle]] pointing to [[differential manifold]]. How about a phrase like "See [[differential manifold]] for more background." -- [[User:Jitse Niesen|Jitse Niesen]] ([[User talk:Jitse Niesen|talk]]) 4 July 2005 21:15 (UTC) (via edit conflict with Paul)

::: Definitely agree there should be such a prominent link. [[User:Dmharvey|Dmharvey]] [[User talk:Dmharvey|Talk]] 4 July 2005 21:17 (UTC)

Wikipedia is not heirarchal. If you start building linked lists and trees into the software through templates, you are breaking the design of Wikipedia. It has purposfully been designed NOT to be heirarchal. This discussion has been gone over many times allready in the past 4 years and there are rules against it. If you want to draw attention to another article, you do what every one else does: write it into the text of the article, explain why, and provide context for the reader. 

Keep in mind, articles can be copied anywhere, in any format, including paper, it has to be assumed that the reader is not reading the article using software and a computer, and thus does not have access to links. Thats why Wikipedia style guidelines are the way they are, articles are self-contained units with no dependencies or heirarchies. [[User:Stbalbach|Stbalbach]] 5 July 2005 03:11 (UTC)

:Basically a [[differentiable manifold]] is a [[topological manifold]], so there is a section of [[topological manifold]] about #differentiable manifolds. This section cannot contain all information on diff. manifolds so there exists now a full article on them (complete with intro and everything), with the most important parts in the section of top. manifolds. This is policy. For this situation were created the templates {main} and {seemain}. One to go in the section and one to go at the top of the corresponding article. Unfortunately the wording of these templates was identical and is still almost. Therefore nobody could knew which was which and they were used interchangeably. Consequently somebody listed them at tfd, because the seemed to be forks. Their creator SEWilco explained that they have different purposes. I voted to keep at first, but then I went and read their talk page descriptions and I found it very difficult to understand which was which. Basically because each uses main in a different meaning. Main as in has the most information and main as in is more general and thus has less information. So I started a discussion and proposed new templates with a clear distinction. These are {subartcleof} and {seesubarticle}. Their names are clear and their wording is clear. You may not like that wording though. The use of two such templates implies a acyclic graph structure. It is possible to have multiple subarticles and also to have multiple superarticles, just as it was with {main} and {seemain}. Stbalbach may rage against the {subarticle} templates, but the fact is that he uses the {main} versions which basically have the same purpose and also imply a hierarchical structure whether he realizes it or not. These templates are not intended to connect articles on the same level. If you want that then you need another template such as {siblingarticle} which does not exist yet. This is hardly an argument against {main} and {seemain} or {subarticle}s. So I can only understand all this by assuming you dislike the current wording. --[[User:MarSch|MarSch]] 5 July 2005 10:45 (UTC)

Since the word subarticle seems to cause problems. What about two other templates
*{details}: For more details on this topic, see the article {1}.
*{background}: For more background on this topic, see the article {1}.
Please discuss at [[Wikipedia:Templates_for_Deletion#Other_wording]] --[[User:MarSch|MarSch]] 5 July 2005 13:41 (UTC)

: Just in case people have not noticed, {{[[Template:subarticleof]]}} is up for deletion at [[Wikipedia:Templates_for_Deletion#Template:Subarticleof]]. [[User:Oleg Alexandrov|Oleg Alexandrov]] 6 July 2005 03:41 (UTC)

:Paul: such multiple relationships are possible. Horizontal grouping cannot be done with these, you need another template for that. So those are not two arguments against this template.
:Dmharvey: I don't understand why you do want the prominent link, but not the hierarchy. What is the difference?\
:Oleg:What about subcategories? Are they somehow not standalone?
:: That's the very point of it. Categories were meant to replace any other form of hierarchical relationship. No need for more. [[User:Oleg Alexandrov|Oleg Alexandrov]] 6 July 2005 15:23 (UTC) 
:Jitse, what do you mean by prefer written out in full? What is wrong with a template? Do you want local variation?  --[[User:MarSch|MarSch]] 6 July 2005 11:25 (UTC)

::My problem with templates is that they are not transparent. If I see a template when I'm editing an article, it's not immediately obvious what it does. It's not a big problem, but I also think it's not a big gain to write it out all the time (use subst: if you are too lazy). I understand that this may lead to variation, but that is quite okay with me. But let me iterate that this is really a miinor issue for me. -- [[User:Jitse Niesen|Jitse Niesen]] ([[User talk:Jitse Niesen|talk]]) 6 July 2005 19:55 (UTC)
::I want the prominent link because anybody looking up tangent bundle should realise that the idea comes from differential geometry. I don't want the hierarchy because [[tangent bundle]] may apply to settings other than differential geometry. As I said above, I'm not an expert, and I don't know much about these other settings. However, take a look at [http://planetmath.org/encyclopedia/ExampleOfFunctorOfPointsOfAScheme.html] on planetmath. Towards the bottom of the article, you'll see a discussion of how you define a "tangent bundle" over a [[scheme (mathematics)]], which is a pretty abstract version of tangent bundle, and has nothing to do with differential geometry. [[User:Dmharvey|Dmharvey]] [[User talk:Dmharvey|Talk]] 6 July 2005 12:56 (UTC)
::: I think sometimes the link is clear from context. Sometimes different wording should be used. I very much agree with Jitse (see [[Wikipedia:Templates_for_Deletion#Other_wording]]) that mindlessly slapping templates on articles illustrating its dependencies is not the way to go. [[User:Oleg Alexandrov|Oleg Alexandrov]] 6 July 2005 15:23 (UTC)

::::Dmharvey, the link is the hierarchy. I guess you object to my calling it a hiereachy and using the word subarticle. But I can only guess, since you haven't explained yet. Do you like my proposed alternatives any better?

::::Oleg, there is nothing mindless about slapping a template on something. Mindless is not an argument. This is one relation that I would like to highlight and I don't see what would be gained by doing that in a different way each time. Saying templates are mindless implies you want all templates to go away.--[[User:MarSch|MarSch]] 6 July 2005 15:38 (UTC)

::::Oh, and forgive me for forgetting, but I can't believe I have to say this yet again. There is nothing to prevent tangent bundle from having another link to scheme. --[[User:MarSch|MarSch]] 6 July 2005 15:41 (UTC)

:::Hi again, there seem to be a lot of proposed alternatives floating around, and I'm not quite sure I understand what they are. The problem I see with having a message like "this is a subarticle of differentiable manifold" on the "tangent bundle" page is that you would then require also "this is a subarticle of scheme" and so on. It just seems unwieldy and unnecessary. My preference is to have an introduction on [[Tangent bundle]] which discusses the tangent bundle in relation to differentiable manifolds as the simplest and most important case, mentions the fact that tangent bundles have analogues in quite different settings (for example in schemes), and then the main article focusses on the differentiable manifold case, and perhaps later we have a section that expands on the various generalizations of the tangent bundle concept. (This discussion reminds me very much of the ongoing debate about [[Derivative]], which is perhaps not a coincidence, given the close relationship between derivatives and tangent bundles :-) ) Personally I would be unable to write such an article because my knowledge of generalisations of tangent bundles is extremely limited.

:::I think the best reason to avoid "subarticles", "main articles" and so on, is that it introduces too much unnecessary rigidity into the structure of the whole encyclopaedia. You really can't predict what people will want to expand on later. [[User:Dmharvey|Dmharvey]] [[User talk:Dmharvey|Talk]] 6 July 2005 16:21 (UTC)

== Mathematics Subprojects, Anyone? ==

I'd like to point out that there are already some projects which can be described as subprojects of this one, and to suggest some new ones:
* listing key publications in the history of mathematics (actually, I think this one is a quixotic task),
* adding suitable citations to all mathematics articles (I see this as much more painless and feasible, but encourage participants to try hard to add only really suitable citations to articles on topics for which they know the textbook literature),
* themes of mathematics: examples include multiplicity of representations, levels of structure, local to global, classification, categorification, (all but the last two just came up in the [[manifold/rewrite]] discussion--- I'd say that ''manifold'' is a ''concept'' in mathematics, but ''classification theorem'' is a theme, and a big one),
* classification theorems could be a category in itself, which would include for example [[Thurston's classification theorem]] and ''Bianchi groups'',
* actually, ''Bianchi group'' could itself be a category, since I for one believe that these guys are worthy of indidivual articles (which I plan to write), and similarly for other classifications (e.g. an article on H<sup>2</sup> should be accessible in one click to someone searching for ''manifolds of constant curvature'', sometimes called ''space forms'').

The goal of the proposed ''themes of mathematics'' subproject could be to ensure that any reader who comes to the math pages here will be likely to encounter at least one of these "big ideas", and will be encouraged to read more about it.  At present, many articles adequatley describe a ''concept'' but fail to point out that this concept exhibits certain ''themes'', an oversight which I think should be systematically rectified.  For some examples of how big ideas can be incorporated into articles, see my discussion in the talk page for the [[manifold/rewrite]] article.

''Categorification'' seems to be a notion some mathematicians hate with a passion, but what I have in mind for the categorification subproject is something I expect we could all agree on: many articles describe concepts but fail to point out that they are examples of categorical notions, and these often arise from an attempt to capture in formal language some theme.  So the categorification subproject could have two complementary goals:
*ensuring that articles mention (probably near the end!) when a concept is an example of a (usually much more general!) concept in category theory, such as a [[pullback square]],
*ensuring that articles on concepts such as pullback square link to articles on important examples of pullback squares.

By the way, the article on [[Thurston's classification theorem]] should clarify the relation with [[uniformitization]].  It should probably cite the little book by Andrew Casson.

--[[User:Hillman|CH ]] [[User_talk:Hillman|(talk)]] 4 July 2005 20:41 (UTC)

:I would say we don't have enough mathematicians (post-doctoral, say) to indulge in subprojects. What is a big deal for us is still getting the top-down view right: fill obvious gaps, list articles, categorise, add biographies, and generally pull things together so that reading the English Wikipedia on mathematics can constitute a liberal education on it. [[User:Charles Matthews|Charles Matthews]] 08:38, 13 July 2005 (UTC)

== Puzzle articles on VfD ==

Several articles on puzzles such as [[burr puzzle]], [[mechanical puzzle]] and [[packing problem]] are up for deletion in two mass listings on VfD [[Wikipedia:Votes_for_deletion/MoreKarlScherer|here]] and [[Wikipedia:Votes_for_deletion/EvenMoreKarlScherer|here]]. &mdash;[[User:Blotwell|Blotwell]] 5 July 2005 00:31 (UTC)

:Thanks, many of them listed aren't the crap that they are thought to be. --[[User:MarSch|MarSch]] 5 July 2005 16:16 (UTC)

::Yes I agree, I have voted to keep these. [[User:Paul August|Paul August]] [[User_talk:Paul August|&#9742;]] July 5, 2005 18:19 (UTC)

== Templates for thought ==

In a magic country [[Shrek_2#Places_and_names_in_Far_Far_Away|far far away]], there lived four templates, explaining what math is all about. They were named "quantity", "space", "change", and "structure" (note that "quantity" is actually about numbers). Here they are in full glory.

{{space}}


{{#switch: {{{1}}}
|u=[[Image:Green Arrow Up.svg|10px]] {{{2}}}
|d=[[Image:Red Arrow Down.svg|10px]] {{{2}}}
|#default=[[Image:Straight Line Steady.svg|10px]]
}}


{{structure}}

I would like to generate some discussion on whether these templates are useful, whether they should be trimmed, or even eliminated, replaced by categories. Wonder what people think. [[User:Oleg Alexandrov|Oleg Alexandrov]] 03:23, 13 July 2005 (UTC)

(From [[talk:Transcendental number]], copied here by [[User:Oleg Alexandrov|Oleg Alexandrov]] 03:23, 13 July 2005 (UTC))

:While I agree that these templates are a bit weird and of dubious utility, I'm not sure I completely support their removal.  I might, but I probably need more convincing.  The fact that lots of other technical subjects seem to have similar templates means that removal from the math pages would damage the consistency of wikipedia across technical subjects, and I do think we should value some uniformity of format at this project.  So what am I saying, either we have to delete all the templates or none of them?  No, that's probably too severe.

:How about this Oleg, can you imagine a mathematics template which we could agree may be useful?  Maybe a much coarser template, and only a single one instead of four of them.  And maybe not organized so bizarrely (structure, quantity, change, and space????  wtf!).  I'd feel better if we still had one organizing template, to ensure consistency with the other technical subjects. -[[User:Lethe|Lethe]] | [[User talk:Lethe|Talk]] 17:31, July 11, 2005 (UTC)

::I despise templates.  I like categories. I can make only one argument in support of templates: if one is learning calculus or trigonometry for the first time, they are a handy tool for trying to cram a whole bunch of facts into your mind at the same time. But once you're no longer cramming for school ... no. They're ugly, they're inaccurate, they chew up space, they impart little knowledge.  [[User:Linas|linas]] 04:58, 13 July 2005 (UTC)
:::Templates are unpopular, justly. I think we only need a few templates, and those for pedagogic purposes. So, no [[bi-complex numbers]], for example. [[User:Charles Matthews|Charles Matthews]] 08:33, 13 July 2005 (UTC)

::::I prefer the simple "See Also" section at the bottom of an article. [[User:Dmharvey|Dmharvey]] [[User talk:Dmharvey|Talk]] 11:38, 13 July 2005 (UTC)

I nominated the templates {quantity} and {strucutre} which have a lot of articles and which are not very related, for deletion. See [[Wikipedia:Templates_for_deletion#Template:Quantity]] and  [[Wikipedia:Templates_for_deletion#Template:Structure]]. [[User:Oleg Alexandrov|Oleg Alexandrov]] 23:09, 14 July 2005 (UTC)

I recently saw for the first time the [[Template:Mathematics-footer|<nowiki>{{mathematics-footer}}</nowiki>]] template

{{mathematics-footer}}

in my opinion, that's all the template we need for mathematics for consistency.  Right? -[[User:Lethe|Lethe]] | [[User talk:Lethe|Talk]] 03:32, July 16, 2005 (UTC)

Kill 'em all.  -- [[User:Dominus|Dominus]] 04:55, 16 July 2005 (UTC)

Well, I got embolded and nominated for deletion the other two of the four templates. See [[Wikipedia:Templates_for_deletion#Template:Change]] and [[Wikipedia:Templates_for_deletion#Template:Space]]. [[User:Oleg Alexandrov|Oleg Alexandrov]] 06:43, 16 July 2005 (UTC)

Fwiw, see also {{tl|mathematics}}. &mdash;[[user:msh210|msh210]] 00:22, 26 July 2005 (UTC)

==Redirects on rfd==
Recently I moved [[Infinite tree (graph theory)]] to [[Tree (set theory)]], because the trees in question don't have to be infinite and don't have much to do with [[Tree (graph theory)|graph-theoretic trees]].  For the same reasons I have proposed that the two redirects, [[infinite tree]] and [[infinite tree (graph theory)]], be deleted. --[[User:Trovatore|Trovatore]] 04:19, 13 July 2005 (UTC)


==[[Infinity-Borel set]]==
I'm having a great argument with myself on the above-named page, and it'd be great if one/some of y'all would come referee. --[[User:Trovatore|Trovatore]] 04:38, 15 July 2005 (UTC)

:Think I've sorted it out now.  Still welcome to come take a look, though. --[[User:Trovatore|Trovatore]] 02:25, 16 July 2005 (UTC)

In fact please do come look at it, particularly the [[Talk:Infinity-Borel set#Alternative definition|Alternative definition]] section on the Talk page. Opinions solicited on which definition is clearer/better. --[[User:Trovatore|Trovatore]] 02:52, 16 July 2005 (UTC)

== Template:Quantity and Template:Structure ==

[[Template:Quantity]] and [[Template:Structure]] have both been listed for deletion at [[WP:TFD|Templates for deletion]]. I don't know enough about mathmatical topics to know how coherent the topics are in either template, so I am requesting that some editors with some math knowledge visit TFD and offer their input to the discussion. [[User:BlankVerse|<span style="color: green;">''Blank''</span><span style="color: #F88017;">''Verse''</span>]]<span style="color: #2554C7;"> </span>[[User talk:BlankVerse|<span style="color: #F660AB;">&empty;</span>]] 07:25, 15 July 2005 (UTC)

== [[H numbers]] ==

Hello. The article [[H numbers]] looks like original research to me. Article links to this web site [http://www.hnumbers.com]. Mathworld hasn't heard of H numbers and I can't find any relevant Google hits. Comments? Thanks for your help, [[User:Wile E. Heresiarch|Wile E. Heresiarch]] 08:32, 16 July 2005 (UTC)
: It looks like patent nonsense to me. [[User:Dysprosia|Dysprosia]] 08:37, 16 July 2005 (UTC)
::Not nonsense, necessarily. One can define such an algebra, I guess. But ''prima facie'' it is OR, and the link page just confirms that. [[User:Charles Matthews|Charles Matthews]] 08:39, 16 July 2005 (UTC)
::: Perhaps I use the term a little too loosely -- it appears to have some rather naive reasoning anyway afaics. Regardless, should be VfD'd for original research, plus it looks like an attempt to legitimize this by having a link from the hnumbers website back to us, and is in a sense advertising. [[User:Dysprosia|Dysprosia]] 08:44, 16 July 2005 (UTC)
::::I agree. It looks like original research to me. [[User:Paul August|Paul August]] [[User_talk:Paul August|&#9742;]] 12:03, July 16, 2005 (UTC)
:I don't think I'd call it research, but anyway let's get it deleted. [[User:Markus Schmaus|Markus Schmaus]] 12:19, 16 July 2005 (UTC)

== [[absolute value]] article rewrite, RFC ==

I've just completed a major revision of the [[absolute value]] article. I've described the changes I've made [[Talk:absolute value|here]]. I'd appreciate any comments/criticisms anyone might have. (Please respond [[Talk:absolute value|here]]) And a good proofread would be greatly appreciated (my eyes now glaze over when I attempt to read it). [[User:Paul August|Paul August]] [[User_talk:Paul August|&#9742;]] 19:56, July 16, 2005 (UTC)
:On my browser (Mozilla 1.7.8 running under Debian Sarge) the Wikipedia logo shows up in the article itself, on top of some of the text of the article.  And the navigation, search and toolbox boxes are nowhere to be found.  Something to do with this line?
::<nowiki>[[Image:Absolute value.png|frame|The graph of the absolute value function for real numbers.]]</nowiki>
:::No, that line isn't the problem.  I copied the article to my sandbox and deleted that line; problem's still there. --[[User:Trovatore|Trovatore]] 20:28, 16 July 2005 (UTC)
:--[[User:Trovatore|Trovatore]] 20:14, 16 July 2005 (UTC)
::I take back the "nowhere to be found" part--they show up at the very bottom of the article, in case that helps in debugging. --[[User:Trovatore|Trovatore]] 20:19, 16 July 2005 (UTC)
:Just tried it in Konqueror -- same result.
Hmm I'll have a look. I forgot to say that any comments (specific to that article) should probably be directed to [[Talk:absolute value|that talk page]]. [[User:Paul August|Paul August]] [[User_talk:Paul August|&#9742;]] 20:58, July 16, 2005 (UTC)

It works ok for me in Safari, Firefox And IE on a MacOS 10.3. [[User:Paul August|Paul August]] [[User_talk:Paul August|&#9742;]] 21:02, July 16, 2005 (UTC)

Same problem in Netscape 7.1 (Windows XP).  I've noted it on the talk page for the article. --[[User:Trovatore|Trovatore]] 21:21, 16 July 2005 (UTC)

: Works fine for me with Firefox, Mozilla, and Konqueror on Fedora Linux. Works equally well with Mozilla and Internet Explorer on MS Windows. [[User:Oleg Alexandrov|Oleg Alexandrov]] 22:30, 16 July 2005 (UTC)
::Yes, but that's after Paul's latest fix.  Try this version: [http://en.wikipedia.org/w/index.php?title=Absolute_value&oldid=18972725]. Clearly there's an issue with the Rf and Ent templates that someone needs to look at. --[[User:Trovatore|Trovatore]] 22:34, 16 July 2005 (UTC)
: That one also works for me with Firefox on both Linux and Windows (did not try the other browsers now). [[User:Oleg Alexandrov|Oleg Alexandrov]] 22:37, 16 July 2005 (UTC)
::Well, Paul said Firefox worked.  I don't have it to check.  Doesn't work in Mozilla 1.7.8. --[[User:Trovatore|Trovatore]] 22:43, 16 July 2005 (UTC)
::Ok I can see we are having a multipage discussion. My fault really. let's continue any future discussions at [[Talk:absolute value]]. I'm heading there now ... [[User:Paul August|Paul August]] [[User_talk:Paul August|&#9742;]] 22:47, July 16, 2005 (UTC)

== Merging of Portal and Category ==

Has anybody noticed the new [[:Category:Mathematics]]? --[[User:R.Koot|R.Koot]] 19:54, 17 July 2005 (UTC)

Nice job, visually.  I'm a bit concerned, though, that the formalist view is presented in a way that might suggest it's the default.  This may not have been the intent, but possibly should be addressed. --[[User:Trovatore|Trovatore]] 20:30, 17 July 2005 (UTC)

:Actually, that bit used to be in the main [[mathematics]] article - now we have something more mushy, and I miss it. [[User:Charles Matthews|Charles Matthews]] 20:58, 17 July 2005 (UTC)

By the bye, it led me to an interesting discussion that I hadn't seen before, and I cast my "yes" votes on math being a science and emperical.  See [[Talk:Mathematics#Is Mathematics a science?]] and [[Talk:Mathematics#Is Mathematics empirical?]]. --[[User:Trovatore|Trovatore]] 20:30, 17 July 2005 (UTC)

: The big challenge is to keep the portal thing up to date. I myself am no big fan of a Wikiportal, whether stand alone or embedded in the category. [[User:Oleg Alexandrov|Oleg Alexandrov]] 20:39, 17 July 2005 (UTC)

:: One of my two main objectives. See [[User_talk:DavidLevinson#Category Mathematics]] --[[User:R.Koot|R.Koot]] 21:45, 17 July 2005 (UTC)

I redirected [[Wikipedia:Wikiportal/Mathematics]] to [[:Category:Mathematics]] now that the contents has been merged. I do agree that the latter is more visible, as there is a link to it from the main Wikipedia page. I also put a note on [[Wikipedia talk:Wikiportal/Mathematics]] saying that the math talk usually takes place on this page, [[Wikipedia talk:WikiProject Mathematics]], and not there. I plan to put the same note on [[:Category talk:Mathematics]]. [[User:Oleg Alexandrov|Oleg Alexandrov]] 17:51, 18 July 2005 (UTC)

I've put [[Template:MathematicsCOTW]] on [[Wikipedia:Templates_for_deletion#July_18|TfD]] as is superseded by [[Template:Wikiportal:Mathematics/Opentask]]]. --[[User:R.Koot|R.Koot]] 18:41, 18 July 2005 (UTC)

==[[Definable number]]==
The [[definable number]] article is in pretty bad shape.  Whatever it is that the article is talking about, it makes some true and useful assertions about--but it's very unclear what it's talking about.  See the [[Talk:Definable number|talk page]]. --[[User:Trovatore|Trovatore]] 04:40, 19 July 2005 (UTC)
: I've rewritten the page.  See talk page for discussion. --[[User:Trovatore|Trovatore]] 05:15, 21 July 2005 (UTC)

BTW why isn't there a template for "math accuracy disputes" or "math articles needing attention" or some such?  I put the <nowiki>{{accuracy}}</nowiki> tag on it and believe I'm completely justified--but that only puts it in the "Accuracy disputes" category, where it could wait forever for a mathematician to notice it.  It would be nice to put it in a more specific needs-attention category.  But then again I suppose that's part of what this page is for. --[[User:Trovatore|Trovatore]] 04:40, 19 July 2005 (UTC)
:I decided to see, replaced <nowiki>{{accuracy}}</nowiki> with <nowiki>{{Math-accuracy}}</nowiki>, meant to hit Alt-P but hit Alt-S by mistake, got the red template link, and now it won't let me change it back.  Something going on with the server?--[[User:Trovatore|Trovatore]] 05:03, 19 July 2005 (UTC)

----
OK, I think I'm done with it for now.  Anyone here who knows about forcing is invited to check my proof that it's consistent with ZFC that there are only countably many OD reals (or better, find a reference). --[[User:Trovatore|Trovatore]] 03:10, 22 July 2005 (UTC)
:Forgot to mention, the proof's not on the main page; it's on the [[Talk:Definable_number#Countably_many_OD_reals|talk page]]. --[[User:Trovatore|Trovatore]] 03:40, 22 July 2005 (UTC)

The article isn't perfect but at least it no longer gives the false impression that there's a univocal, mathematically well-understood notion of what it means to be a not-further-specified "definable" real.  Unfortunately there are lots of pages that link to the page, and some of them do give that impression.  Not sure what to do about that yet. --[[User:Trovatore|Trovatore]] 03:10, 22 July 2005 (UTC)

==Mnenta==

Anybody here heard of [[mnenta]]? It's the only contribution from some IP address, I cannot find it in MathSciNet or OED, and none of the 14 pages returned by Google is relevant, so unless somebody speaks up it will go to VfD. -- [[User:Jitse Niesen|Jitse Niesen]] ([[User talk:Jitse Niesen|talk]]) 19:39, 19 July 2005 (UTC)
:Sounds like the sort of thing [[Clifford Pickover]] does; but I don't remember it specifically. Whether this should, if true, save it from VfD is another question. [[User:Pmanderson|Septentrionalis]] 19:43, 19 July 2005 (UTC)

This is a dicdef at best without some relevance to the rest of mathematics; I say VFD.  --[[User:Kinser|Kinser]] 23:16, 19 July 2005 (UTC)

If someone knows Pickover well enough to e-mail him, I say go for it; maybe the article can be brought up to a level worth keeping.  But if there's no serious, immediate prospect of improvement, I'll vote '''delete'''--the article as it stands is very uninformative. --[[User:Trovatore|Trovatore]] 23:52, 19 July 2005 (UTC)

Without a source, this is unverifiable and should be deleted. [[User:Paul August|Paul August]] [[User_talk:Paul August|&#9742;]] 03:47, July 20, 2005 (UTC)

Sounds like a mini-consensus.  Jitse, why don't you put it on VfD and get the ball rolling?  If the article has defenders, that'll concentrate their minds. --[[User:Trovatore|Trovatore]] 04:12, 20 July 2005 (UTC)

Went ahead and did it myself--hope you don't mind. --[[User:Trovatore|Trovatore]] 05:48, 21 July 2005 (UTC)

== Puzzle VfD ... Its baaaack ...  ==

The puzzle articles are under renewed attack.

*[[Wikipedia:Votes for deletion/KarlSchererRevisited1]]
*[[Wikipedia:Votes for deletion/KarlSchererRevisited2]]
*[[Wikipedia:Votes for deletion/KarlSchererRevisited3]]
*[[Wikipedia:Votes for deletion/KarlSchererRevisited4]]
*[[Wikipedia:Votes for deletion/KarlSchererRevisited5]]
*[[Wikipedia:Votes for deletion/KarlSchererRevisited6]]
*[[Wikipedia:Votes for deletion/KarlSchererRevisited7]]
*[[Wikipedia:Votes for deletion/KarlSchererRevisited8]]

I am concerned that these VfD's are being pushed by someone who has it in for puzzles. I am concerned that the people voting to delete never actually contribute to math or physics articles.  In a moment of heated anger, were I to actually get that heated, then I would say that these people are anti-social vandals, and should be treated as such.  But everyone knows I'm not a hot-head, right?  [[User:Linas|linas]] 15:38, 20 July 2005 (UTC)

:I think they all contain valid encyclopedic content. This is getting tiresome. [[User:Paul August|Paul August]] [[User_talk:Paul August|&#9742;]] 18:27, July 20, 2005 (UTC)

:: Yeah, -Ril- started some sort crusade Karl Scherer after he added 'spam' to some articles (which it barely was imho).  --[[User:R.Koot|R.Koot]] 18:47, 20 July 2005 (UTC)

It should be noted that the articles are up for VFD as neologistic categorisation by Karl Scherer. Coupled with a distinct lack of non-categorisation content, existing only to fluff the categorisation enough to have an article for each class. The 100+ that have already been VFD'd were done so for predominantly the same reason. 

Wikipedia is meant to be an encyclopedia, and not something to push your POV of how things should be categorised. Neither is it a collection of all information under the sun.[[User:-Ril-|<nowiki>~~</nowiki><nowiki>~~</nowiki>]] 22:10, 20 July 2005 (UTC)

: You have to categorize articles one way or another. And I think Karl did a pretty good job. --[[User:R.Koot|R.Koot]] 22:19, 20 July 2005 (UTC)

== Dotted box template up for deletion ==

I nominated [[Template:ImportantLabeledEquation]] up for deletion (this was a bit discussed above, see  [[Wikipedia talk:WikiProject Mathematics#Dotted framebox around formulas]]). I myself think that dotted box looks ugly, and indenting should be enough to display a math equation or defintion. [[User:Oleg Alexandrov|Oleg Alexandrov]] 18:43, 20 July 2005 (UTC)

The vote for deletion is at [[Wikipedia:Templates for deletion#Template:ImportantLabeledEquation]]. [[User:Oleg Alexandrov|Oleg Alexandrov]] 18:44, 20 July 2005 (UTC)

: Somewhere there one also can find [[Template:Calculus2]] which is not necessary anymore, as it is just an old version of [[Template:Calculus]]. [[User:Oleg Alexandrov|Oleg Alexandrov]] 00:40, 21 July 2005 (UTC)

==[[:Category:Integer sequences]]==
:''(Moved to here from my talk page.)'' [[User:Linas|linas]] 17:17, 24 July 2005 (UTC)

I notice you recently recategorised [[quasiperfect number]] to 'integer sequences', but it seems odd to mark it as such given that no such numbers are known to exist. Do you see the categorisation as extending to any boolean property defined on integers (or maybe the naturals)? (I ask in all humility - it isn't clear to me whether the categorisation is appropriate or not.) Either way, it may also merit a clarification on ''Category::Integer_sequences''. [[User:Hv|Hv]] 16:30, 24 July 2005 (UTC)

:Hi Hv, If you know of a better category, please recategorize as appropriate. I was attempting to do a broad cleanup; the articles I placed in [[:Category:Integer sequences]] I had found scattered about [[:Category:Numbers]], [[:Category:Integers]], [[:Category:Number theory]], [[:Category:Number sequences]], a few in some odd corners, and a few without any cats at all. Rather than having them scattered all about, I thought I'd at least pull them into one place.  There may be a better way of organizing these, but I don't know of one/can't think of one at this time.  If you have ideas, let me know.  At any rate,  [[quasiperfect number]] seemed a better fit there than elsewhere.  [[User:Linas|linas]] 16:44, 24 July 2005 (UTC)

:Hm, maybe [[:Category:Divisor-related sequences]], since there seems to be a dozen or so that can be loosely defined in this way, e.g. [[abundant number]]. [[User:Linas|linas]] 17:05, 24 July 2005 (UTC)

:And then, there's [[:Category:Totient-related sequences]] as well; e.g. [[highly cototient number]]. Is there a common name for these things?  [[User:Linas|linas]] 17:13, 24 July 2005 (UTC)

:Sequences can be finite, of course, but this category might be better named [[:Category:Kinds of integer]] (or '''Types''' or '''Classes'''). '''Sequences''' should be kept for those where the order matters, like [[Fibonacci sequence]] or [[John Conway]]'s [[Speak-and-say sequence]]. [[User:Pmanderson|Septentrionalis]] 19:39, 24 July 2005 (UTC)

::I agree. I saw Linas put [[primitive semiperfect number]] in [[:Category:Integer sequences]] and I thought that it was very odd to call it a sequence, but I forgot to follow up on it. How about something like [[:Category:Divisibility properties]]? -- [[User:Jitse Niesen|Jitse Niesen]] ([[User talk:Jitse Niesen|talk]]) 19:58, 24 July 2005 (UTC)

:::I'm not sure it's a divisibility property.  How about [[:Category:Properties of natural numbers]]?  Or maybe a [[List of properties of natural numbers]]. --[[User:Trovatore|Trovatore]] 20:10, 24 July 2005 (UTC)
Something in the spirit of [[:Category:Properties of natural numbers]] looks good to me. But can one shorten this in some way? [[User:Oleg Alexandrov|Oleg Alexandrov]] 21:08, 24 July 2005 (UTC)

:[[:Category:Integer properties]] is shorter, if a bit looser. But presumably a description could explain that it is appropriate for properties defined over more restricted sets as well, such as naturals or positive integers. [[User:Hv|Hv]] 23:35, 24 July 2005 (UTC)
::Or just make sure the articles somewhere say the property only applies to non-negative/positive integers. They probably should anyway. [[User:Pmanderson|Septentrionalis]] 23:39, 24 July 2005 (UTC)

::I'd prefer [[:Category:Properties of integers]].  Somehow "integer properties" sounds like something that's an integer and at the same time a property. --[[User:Trovatore|Trovatore]] 00:16, 25 July 2005 (UTC)
::: I like Trovatore's suggestion. [[User:Oleg Alexandrov|Oleg Alexandrov]] 01:33, 25 July 2005 (UTC)

Well, there are 75 articles in [[:Category:Integer sequences]]; and it would be appropriate to introduce some subcategories, such as [[:Category:Divisor-related numbers]] and [[:Category:Totient-related numbers]]. The first seems to be a category over at mathworld, the second a neologism. I was fishing for a commonly-used, commonly-accepted name for these two cats. In all cases, I assume that the category will also contain "theorems pertaining to divisor-related numbers" and "properties of numbers that are in the divisor-related number category".  I think we can add wording stating this explicitly,once we know the correct, commonly accepted cat names.  [[User:Linas|linas]] 02:20, 25 July 2005 (UTC)

:Personally I think "Divisor-related numbers" is horrible.  Every number is divisor-related (for example, it has divisors, is a divisor of other numbers, etc).  The things in the category are not numbers, but rather ''properties'' of numbers, and the name should reflect that. --[[User:Trovatore|Trovatore]] 01:43, 27 July 2005 (UTC)

:And just in passing, I really wouldn't look to MathWorld, or PlanetMath either, as an example of how to do anything. --[[User:Trovatore|Trovatore]] 01:47, 27 July 2005 (UTC)

::A category such as [[:Category:Divisors of integers]] would be useful, and could be a subcategory of both the 'integer sequences' and 'number theory' categories. It would not just hold sequences, but I think people get a bit hypnotised by the sequence thing. [[User:Charles Matthews|Charles Matthews]] 10:11, 27 July 2005 (UTC)
::: Taken literally, which categories usually are, this would be coterminous with [[:Category:Integer]]. I presume this is not what is meant; but what '''is''' meant? [[User:Pmanderson|Septentrionalis]] 14:35, 27 July 2005 (UTC)
::Quite a lot of number theory takes an integer ''n'', looks at its set of divisors (a [[multiset]], if you want) and then defines some function ''f''(''n'') via that multiset. So, it's a substantial topic, and not really a tautologous thing either. [[User:Charles Matthews|Charles Matthews]] 14:43, 27 July 2005 (UTC)
:::Perfectly true (pun unintentional). And now I see what you mean. If the whole category becomes [[:Category:Properties of integers]], the subcat should be [[:Category:Properties of divisors]] or even [[:Category:Properties of divisors of integers]] (although I'd rather not go ''there''). I will propose a move of the whole category now, to move that part of this discussion where it will do something. [[User:Pmanderson|Septentrionalis]] 15:15, 27 July 2005 (UTC)

* There is some misunderstanding; its about "numbers related through functions of the [[divisor function]]", and not whether or not numbers have divisors.[[User:Linas|linas]] 17:34, 27 July 2005 (UTC)

:Which is precisely why "divisor-related numbers" is a bad name.  If you have a category called "foo numbers", the individual articles should logically be about individual foo numbers.  (So we shouldn't have any categories called "foo numbers".)  (Maybe that was your point--I can't tell from the comment above and haven't bothered to trace through the history to see which comments are yours.) --[[User:Trovatore|Trovatore]] 06:20, 31 July 2005 (UTC)

::There is a [[:Category:Prime numbers]] which contains articles about related theorems. [[User:Linas|linas]] 23:53, 1 August 2005 (UTC)

* I vote we keep the discussion here, instead of CfD, since almost no mathematicians hang out on CfD. I promise to make the changes myself, if we can build a reasonable consensus on what the naming should be. [[User:Linas|linas]] 17:34, 27 July 2005 (UTC)
**Fine; CfD has been notified in case anyone there cares. The category talk page will refer them here. [[User:Pmanderson|Septentrionalis]] 01:59, 2 August 2005 (UTC)

== [[3.14]] ==
The article for this number is up for deletion at [[Wikipedia:Votes for deletion/3.14]]. [[User:Uncle G|Uncle G]] 02:01:35, 2005-07-25 (UTC)

==Visualstatistics.net==
[[User:Cruise|User:]]{{User|Cruise}} has recently added a number of links to Visualstatistics.net and vstat.net. A number of the pages on this site about social science topics (e.g. [[slavery]]) are a mix of facts and patent nonsense, and I have thus removed them. I have no idea about the quality of the math and statistics pages linked, e.g. at [[multiple correlation]], but it would be a good idea if someone double checked them. - [[User:SimonP|SimonP]] 03:20, July 25, 2005 (UTC)
:the [[Multiple correlation]] link looks somewhat simple-minded but not utter bilge, at least at a glance. [[User:Pmanderson|Septentrionalis]] 22:34, 25 July 2005 (UTC)

== PNG vs HTML ==

I have a disagreement over at [[cardinal number]] about using inline TeX which becomes HTML. I argue against it (that is, use HTML if TeX gives PNG), while the other opinion seems to be that if one really want HTML then one should set up the browser settings that way. Wonder what people think on this issue. Thanks. [[User:Oleg Alexandrov|Oleg Alexandrov]] 22:40, 26 July 2005 (UTC)

:The advantages to using markup like "<nowiki><math>|X| \le |Y|</math></nowiki>" rather than "<nowiki>|&amp;nbsp;''X''&amp;nbsp;| &amp;le; |&amp;nbsp;''Y''&amp;nbsp;|</nowiki>" which in turn is automatically turned into HTML such as <nowiki>| <i>X</i> | ≤ | <i>Y</i> |</nowiki> are numerous, by writing formulae in an abstract markup language they can be turned into HTML, PNGs (and in the future MathML) on the fly rather than being restricted to just one of those options, it's not future proof, it's restrictive and it's bad for accessability to use html rather than the math module.
:If you have a problem with how the math module is converting LaTeX into HTML please file a bug at http://bugzilla.wikimedia.org/ . —[[{{ns:2}}:Ævar Arnfjörð Bjarmason|Ævar Arnfjörð Bjarmason]] 22:59:06, 2005-07-26 (UTC)

::This is an issue which comes up frequently and generates long discussions; see e.g. [[Wikipedia talk:WikiProject Mathematics/Archive4(TeX)]]. The majority of mathematicians seem to prefer HTML, as documented on [[Wikipedia:How to write a Wikipedia article on mathematics]]. 
::My personal opinion is that given this situation, the author of an article gets to decide, which for [[cardinal number]] means that the HTML should not have been changed into <nowiki><math></nowiki> (if my cursory skim of the history is correct). However, I care so little about it that I won't even revert. I think the only permanent solution is technical, and that it would be more constructive to find out how to achieve a technical solution (of course, just filing bugs won't help much). -- [[User:Jitse Niesen|Jitse Niesen]] ([[User talk:Jitse Niesen|talk]]) 23:24, 26 July 2005 (UTC)

::I found out in a discussion with Pmanderson that &alefsym; doesn't show up correctly for everyone.  I think that by itself is a pretty good argument for LaTeX.  Being able to use the aleph symbol inline is indispensible. --[[User:Trovatore|Trovatore]] 23:56, 26 July 2005 (UTC)
::: Right, if you have no choice then you use PNG. If you have a choice, you use HTML. [[User:Oleg Alexandrov|Oleg Alexandrov]] 03:30, 27 July 2005 (UTC)

: Thankfully the HTML-<nowiki><math></nowiki> renderer uses the proper fonts now, so it wouldn't be bad if <nowiki><math></nowiki>  was used in articles (judiciously of course as it spontaneously springs to PNG if it is used a little too liberally) as it looks decent now, but I would suggest that PNG be reserved for inline as it has been. [[User:Dysprosia|Dysprosia]] 12:13, 5 August 2005 (UTC)

== Number articles up for deletion ==
* [[List of numbers ordered by Google rating]] ([[Wikipedia:Votes for deletion/List of numbers ordered by Google rating|discussion]])
* [[99999999]] ([[Wikipedia:Votes for deletion/99999999|discussion]])
* [[List of numbers that are not primes]] ([[Wikipedia:Votes for deletion/List of numbers that are not primes|discussion]])
* [[31999998]] ([[Wikipedia:Votes for deletion/31999998|discussion]])
The aforementioned articles are all up for deletion. [[User:Uncle G|Uncle G]] 02:18:02, 2005-07-27 (UTC)

:I voted to delete them all. [[User:Paul August|Paul August]] [[User_talk:Paul August|&#9742;]] 03:35, July 27, 2005 (UTC)

==Symmetry==

I noticed that there is no [[:Category:Symmetry]]. Should there be? [[User:Charles Matthews|Charles Matthews]] 10:13, 27 July 2005 (UTC)

: I think it is a good idea. Here are a bunch of articles which could go there:
[[Axis of symmetry]] [[Talk:Axis of symmetry| ]] --
[[Broken symmetry]] [[Talk:Broken symmetry| ]] --
[[Circular symmetry]] [[Talk:Circular symmetry| ]] --
[[Freiling's axiom of symmetry]] [[Talk:Freiling's axiom of symmetry| ]] --
[[Homological mirror symmetry]] [[Talk:Homological mirror symmetry| ]] --
[[Mirror symmetry]] [[Talk:Mirror symmetry| ]] --
[[P-symmetry]] [[Talk:P-symmetry| ]] --
[[Plane of symmetry]] [[Talk:Plane of symmetry| ]] --
[[Rotational symmetry]] [[Talk:Rotational symmetry| ]] --
[[Spacetime symmetries]] --
[[Spontaneous symmetry breaking]] [[Talk:Spontaneous symmetry breaking| ]] --
[[Symmetry]] [[Talk:Symmetry| ]] --
[[Symmetry group]] [[Talk:Symmetry group| ]]

:(maybe not all of them). [[User:Oleg Alexandrov|Oleg Alexandrov]] 15:47, 27 July 2005 (UTC)
::Not [[Freiling's axiom of symmetry]], I think. [In fact, if this and [[Symmetry group]] are removed, I see a good [[:Category:Physical symmetry]]. 17:13, 27 July 2005 (UTC)] [[User:Pmanderson|Septentrionalis]] 16:10, 27 July 2005 (UTC)
:::Hmm. Are you sure? This lumps together a bunch of otherwise unrelated topics. In physics, p-symmetry and spontaneous symmetry breaking are ... well, related, but in a subtle way. And these have little to do with some of the math concepts of symmetry ... If we create this cat, then we need to rethink the VfD for template:Numbers which lumped together a bunch of "unrelated" articles with the word "number" in the title. However, I think its lots of fun to have a [[list of all math articles with the word "number" in the title]] and it would be fun to have a similar list for symmetry.  [[User:Linas|linas]] 17:05, 27 July 2005 (UTC)
I agree about not including [[Freiling's axiom of symmetry]]. Let us keep this geometric/physical. So for example, the article [[symmetry of second derivatives]] should not be there either. [[User:Oleg Alexandrov|Oleg Alexandrov]] 17:24, 27 July 2005 (UTC)
: And this asks an interesting question. If we adopt this cateogry as mathematical, putting it in the [[list of mathematics categories]], should all the physics articles in [[:category:symmetry]] be added to the [[list of mathematical topics]]? (For example, [[CPT symmetry]].) [[User:Oleg Alexandrov|Oleg Alexandrov]] 17:24, 27 July 2005 (UTC)
::Not very harmful, I think. One can trust the physicists eventually to bend any mathematical concept to the breaking point. But if you think about [[rotational symmetry]] and [[circular symmetry]], for example, it is a bit perverse to say that one is mathematics and the other isn't. [[User:Charles Matthews|Charles Matthews]] 05:42, 28 July 2005 (UTC)
::: Thanks Charles. [[User:Oleg Alexandrov|Oleg Alexandrov]] 15:29, 28 July 2005 (UTC)
== Proposal: rename [[:Category:Math lists]] ==

The word Math (as opposed to Maths) is quite jarring for many Brits, and to me it feels somewhat too informal for a category title anyway. How about moving articles in this category to [[:Category:Mathematical lists]]? This is a task which bots can perform fairly easily, I believe. [[User:Lupin|L]][[User talk:Lupin|upin]] 23:32, 27 July 2005 (UTC)
: Fine with me. If agreed on the change, my [[User:mathbot|bot]] can take care of it. (However, under no circumstances will I rename my bot from ''mathbot'' to ''mathsbot'' :) [[User:Oleg Alexandrov|Oleg Alexandrov]] 00:13, 28 July 2005 (UTC)
::Of course it should be renamed (the category, not the bot), see [[Category talk:Mathematics stubs]] for a precedent. -- [[User:Jitse Niesen|Jitse Niesen]] ([[User talk:Jitse Niesen|talk]]) 12:18, 28 July 2005 (UTC)
I think [[:Category:Math lists]] better be renamed to [[:Category:Mathematics lists]], rather than [[:Category:Mathematical lists]]. Any objections to that? :) [[User:Oleg Alexandrov|Oleg Alexandrov]] 15:29, 28 July 2005 (UTC)

:Picking nits, "Mathematics lists" could be interpreted by someone who knew nothing as being "Lists of various (kinds of) mathematics". I can't think of a  meaning for "Mathematical lists" other than "lists of a mathematical nature". So I slightly prefer the latter. But I'm really not that bothered. [[User:Lupin|L]][[User talk:Lupin|upin]] 15:34, 28 July 2005 (UTC)

I see your point about ''mathematical'' instead of ''mathematics'' (and I agree). Lupin, I think you will need to submit a formal request at CfD for [[:Category:Math lists]] to be deleted, and the articles moved  to [[:Category:Mathematical lists]]. I expect no problems with that, and then I can start the move. [[User:Oleg Alexandrov|Oleg Alexandrov]] 22:06, 28 July 2005 (UTC)
: I actually already moved the articles. Should we formally ask for the [[:Category:Math lists]] to be deleted, or can an admin among us just quickly get rid of it? [[User:Oleg Alexandrov|Oleg Alexandrov]] 02:41, 29 July 2005 (UTC)

== blahtex: a LaTeX to MathML converter ==

Someone called "kate" once said to me:
:''the best way to get this implemented is to write the code :-)''

I took her advice. Following a few weeks of down-and-dirty coding, I would like to announce '''blahtex version 0.1''', a [[LaTeX]] to [[MathML]] converter designed specifically for Wikipedia (or more generally for the [[MediaWiki]] environment).

You can try it out interactively [http://abel.math.harvard.edu/~dmharvey/blahtex/test.php here]. You can also see some samples extracted from Wikipedia [http://abel.math.harvard.edu/~dmharvey/blahtex/wp-samples/page-99.php here].

'''Important note:''' Your mileage may vary depending on OS/browser. I will get back to this in a moment. For now, I'll just say that your best bet is Mozilla/Firefox on Windows; if you're on a Mac then I'm afraid the world of MathML is rather inaccessible right now; if you're on Linux or another Unix then I really have no idea, I'm guessing Mozilla will be your best bet.

Before getting to more details, let's just check out this screenshot of blahtex plugged into MediaWiki:

[[Image:blahtex_screenshot.png|frame|Screenshot]]
<br style="clear:both" />

Here's the wiki markup I used for this:

 <nowiki>'''Archimedes''' was a [[Greek]] [[mathematician]] who is best known for the myriad mathematical</nowiki>
 <nowiki>[[notation]]s that he invented, most of which are still in use today. His earliest work included</nowiki>
 <nowiki>devising simple [[inline equation]]s such as <math>\sin x = \cos^2(y+t)</math> and</nowiki>
 <nowiki><math>x^2 + y^2 = -e^{-\theta}</math>. He pioneered the use of greek symbols such as</nowiki>
 <nowiki><math>\alpha</math> in English writing. While performing complicated calculations such as</nowiki>
 <nowiki><math>\sum_{i=1}^3 i^2 = 47</math>, he noticed that despite the baseline of the equation</nowiki>
 <nowiki>lining up nicely with the surrounding text, the so-called [[displayed equation]]</nowiki>
 <nowiki>: <math>\displayed\sum_{i=1}^3 i = 46, \qquad \textrm{unless} 46 \not= 47</math></nowiki>
 <nowiki>was probably better value. A similar effect occurred for integrals such as</nowiki>
 <nowiki><math>\int_0^1 \sin^2 x \, dx</math>. He marked this up using the kludgy "\displayed"</nowiki>
 <nowiki>command, although he suspected that later and greater thinkers would come up with something</nowiki>
 <nowiki>better. When he couldn't make up his mind he would write</nowiki>
 <nowiki>: <math>\displayed F(x) = \begin{cases} \left\uparrow\frac{\partial^2 G}{\partial u \partial v}\right\}</nowiki>
 <nowiki>& \textrm{if the sky was \bf blue}, \\ A_0 + \cdots + A_k & \textit{if Troy was on the attack.}</nowiki>
 <nowiki>\end{cases}</math></nowiki>
 <nowiki>He also invented the polynomial rings <math>\mathbf{R}[x]</math>,</nowiki>
 <nowiki><math>\mathcal{C}[y]</math> and <math>\boldsymbol{\mathcal{C}[z]}</math>, and being</nowiki>
 <nowiki>fluent in Chinese he was comfortable writing things like</nowiki>
 <nowiki>:<math>\displayed 钱 = \sqrt{不好},</math></nowiki>
 <nowiki>although historians have debated whether his Chinese really was all that good.</nowiki>

How did I get this screenshot? I installed MediaWiki on my laptop (an [[iBook]] G3), and fiddled around with a few bits of the code to change the MIME type etc, and redirected the math code so that it fed into blahtex instead of texvc. A rather ugly hack. It doesn't really work. I don't recommend it. But it's enough to get something like the image above. The browser was Mozilla running on a Windows XP machine.

=== Blahtex's main features ===

==== backwardly compatible with [[texvc]] ====

In other words, all the equations already present on Wikipedia won't break.

Hmmm. A big claim. Probably not entirely true. In any case, a proposition capable of empirical testing.

Here's how I tried to test it. First, I downloaded a database dump of the current content of the English Wikipedia, from http://download.wikimedia.org/wikipedia/en/pages_current.xml.gz. (I got the file dated 14th July 2005. It's 3.4 GB uncompressed, 1GB compressed.) Then I wrote some code to suck out everything surrounded by <nowiki><math></nowiki> tags. After throwing out some junk caused by people enclosing <nowiki><math></nowiki> tags inside nowiki tags :-), and discarding duplicates, we are left with 50193 distinct equations (71561 including duplicates; we lost about 80 "equations" as junk). If you want to play with them, you can get the full list [http://abel.math.harvard.edu/~dmharvey/blahtex/equations.txt.gz here], one line for each equation. I set my poor laptop the task of running texvc on all 50193 equations, which took about nine hours. (About 1800 of them failed to work with texvc; casual inspection suggests these are things in people's personal sandboxes, and markup being discussed on talk pages.) Then I ran blahtex on all the equations as well (under ten minutes :-)). Actually I did this several times during development, to gauge progess.

For ease of comparison, I have collected the result together [http://abel.math.harvard.edu/~dmharvey/blahtex/comparison.tar.gz here] (36 MB). Uncompress it and load up "index.xml" in your browser. You'll find the entire corpus of English Wikipedia equations, divided up pseudo-randomly into 256 pages (each containing about 200 equations), with the LaTeX, PNG output from texvc, and MathML output side-by-side for handy comparison. As mentioned earlier, I've put one sample page up on the web [http://abel.math.harvard.edu/~dmharvey/blahtex/wp-samples/page-99.php here]. 

(''Warning:'' there are about 50000 small files in there, so if your filesystem is anything like the one on my mac, it could take up to 200 MB of hard drive space, even though there's only about 100 MB of data.)

So you can have a look yourself to see what blahtex's strengths and weaknesses are.

I should mention that I studied portions of the texvc code quite carefully to work out exactly what it was doing, and which LaTeX commands it accepts.

==== displayed and inline equations ====

Blahtex has command line options for choosing either inline equations (for use in running text) or displayed equations.

In my opinion, Wikipedia's greatest math rendering weakeness at the moment is the inability to do inline equations ''well''. You can do simple stuff with HTML (although it renders inconsistenly with the displayed PNGs), and you can sure try to do PNGs inline, but they look pretty awful. In contrast, one of MathML's wonderful features is that it automatically lines up baselines and fonts with the surrounding text.

As you can see from the markup I gave above, I used the "\displayed" command to get displayed mode. This is just a temporary fix because I don't know enough about MediaWiki internals to make up another math tag (e.g. <nowiki><mth></nowiki>, or something like that). If blahtex is ever plugged into MediaWiki on a real site, I don't expect "\displayed" to be used.

You might point out that the font sizes don't match properly in the screenshot above, but I'm pretty sure this is more a result of my complete ignorance about CSS and stylesheets and MediaWiki internals, rather than any fault in MathML or the browser's rendering. As soon as someone who understands these things gets involved, the font size matching problem will go away.

==== unicode happy ====

As you can also see from the screenshot, blahtex is quite happy to accept [[Unicode]] characters. Try typing some chinese characters into the [http://abel.math.harvard.edu/~dmharvey/blahtex/test.php interactive form], either in math mode or inside text blocks (like \textrm). I'm sure that our friends at the non-English Wikipedias will find this very pleasant. Since MathML is based on XML, which in turn uses Unicode, it seems a bit silly not to support it.

Blahtex accepts input in UTF-8, and output is pure ASCII, but all internals are done with wide 32-bit characters, so it should be trivial to implement different input/output encodings if necessary.

==== GNU GPL ====

I will be releasing the code under the [[GNU GPL]], probably in the next week or so. I just need to remove various profanities from the code and generally clean it up. Stay tuned.

==== written in C++ ====

Except for a [[yacc]] parser, it's all written in [[C plus plus|C++]], with a healthy dose of [[Standard Template Library|STL]]. Probably C++ isn't the best choice of language from a technical point of view, but it has the advantage that I know it, and so do lots of other people. I think this will encourage collaborative hacking in a way that is not possible for texvc, which is written in [[OCaml]], which not many people know.

=== Browser compatibility issues ===

So far all is well and good. Now we come to the hard stuff.

There are actually two completely separate questions concerning browser compatibility.

The first question is: how does the browser know that it should be trying to translate MathML tags? In an ideal world, the following would happen. Joe loads up a Wikipedia page with equations on it. If he's running Mozilla or Firefox, everything just works. If he's running internet explorer and has MathPlayer installed, then everything just works. If he doesn't have MathPlayer installed, he gets a dialog box telling him that he should install MathPlayer; if he chooses not to, he gets the next best alternative (e.g. PNGs). If he's running a completely MathML-unaware browser (like [[Safari (web browser)|Safari]]), then he should just get the PNGs again (perhaps with a message telling him to get a different browser!!)

I don't know how to make this happen. For various technical reasons that I don't understand very well, it seems like a very difficult problem. I will leave this to the experts to sort out.

The second question is: assuming our browser ''does'' understand MathML and knows that it should be doing so, how does its rendering look? Does it render things "correctly"? Do different browsers give different renderings?

Let me summarise my current understanding of the situation here. Overall, I think the best browser I've played with is Mozilla/Firefox on Windows. It does have a bunch of bugs (which I will say more about on another day), but it does give the best overall effect. You'll notice that there is a radio button for "Mozilla tweaks" on the interactive site. This activates a bunch of tweaks to the output to compensate for some of Mozilla's bugs. Almost all of my testing has been on Windows Mozilla. MathPlayer for Internet Explorer is occasionally competitive, but its pixelation doesn't get corrected by XP, which is a major disadvantage, and sometimes it does some really weird stuff with spacing.

(NB: if you're on Windows and your equations look pixelated in Mozilla, you might want to try turning on ClearType. On XP, go right-click on desktop, then Properties, then Appearance, then Effects, then "Smooth edges of screen fonts" should be set to "ClearType".) 

Sadly, on the Mac, you don't really have anything very good. Mozilla's support got broken a few versions ago. I'm not sure why they're taking so long to fix it. You could try running an old version (I think 1.3 is ok), but it doesn't look that great. Despite being a big mac fan, I concede that currently Windows kills the Mac in this department &mdash; you have no idea how hard it was for me to admit that :-)

As for other OSes, I'm pretty ignorant. Maybe someone else can report on the situation.

You could also try [[Amaya (web browser)|Amaya]]. It's a bit frustrating to work with (the mac version anyway), but sometimes helpful for debugging.

=== What to do now ===

'''I need your help'''. Play with blahtex and help me find and squish all those evil bugs.

Of course it would be fantastic if a MediaWiki developer knows how to plug blahtex into MediaWiki (at least the "MathML - experimental" option). Drop me a line if that's you.

I am going to run a blahtex development page at http://meta.wikimedia.org/wiki/Blahtex. '''Probably the best place to continue this discussion is over there. In particular you can report bugs there.'''

=== now I'm off to bed ===

Goodnight guys and gals, I hope you enjoy playing with blahtex.

[[User:Dmharvey|Dmharvey]] [[User talk:Dmharvey|Talk]] 02:17, 28 July 2005 (UTC)

=== Comments ===
''"If he doesn't have MathPlayer installed, he gets a dialog box telling him that he should install MathPlayer"''

:Nooooooooooooo!  
:He gets a note on the top of the page that it would look better with Mathplayer, but it displays PNGs for now, letting him decide that he wants to install it when he gets around to it. :-) 
:Otherwise, '''very very cool'''. 
:I don't know much about mathML, but is it possible that little spacing issues could be from your code?  Or is that just the browser's interpretation of the mathML?  Specifically,
::''Moved to [[m:Blahtex/Bugs and feature requests]]''
:(HTML id tags would be helpful.) :-) - [[User:Omegatron|Omegatron]] 05:51, July 28, 2005 (UTC)

:: Hi Omegatron, thanks for your interest. I'd appreciate it if you could list the bugs on the page I mentioned at meta.wikipedia.org. Right now I want to concentrate on getting the source to a level appropriate for release. I'll come back to those bugs in a little while. [[User:Dmharvey|Dmharvey]] [[User talk:Dmharvey|Talk]] 12:05, 28 July 2005 (UTC)

Very promising. Almost all formulas are understandable in my browser at work (Firefox 1.0 on Linux with Fedora Core release 2), though the spacing is often wrong; almost certainly the browser fault. Re 99d1d9133a0a5551e047a9560783aedc, there is a special latex code which should have been used, I think \ll, so it's not blahtex's fault. I hope dmharvey forgives me for saying that my personal opinion is that translating latex to mathml is the easy part and there is a lot that needs to be done, but as I said, it's a very promising start. I poked a bit around in the mediawiki code lately, going through some of the texmf bugs, and I'd be quite willing to lend a hand (within my time constraints, of course). -- [[User:Jitse Niesen|Jitse Niesen]] ([[User talk:Jitse Niesen|talk]]) 12:11, 28 July 2005 (UTC)

: Yes, I forgive you :-). I agree it's probably the easy part, but not quite as easy as I had thought it would be several weeks ago when I started trying to write the code. :-) There ''are'' of course other translators out there, but in my opinion they have a lot of weaknesses, and I hope that eventually blahtex will be better. Anyway, maybe having a working translator will spur other people on to fix the MediaWiki end of things. Your assistance is appreciated. [[User:Dmharvey|Dmharvey]] [[User talk:Dmharvey|Talk]] 12:35, 28 July 2005 (UTC)

:I don't understand why it's difficult.  They already have rudimentary mathml output in the preferences, and blahtex looks like it works for everything.  So isn't it just a matter of swapping blahtex in place of the older experiment?  Could still leave the "experimental" tag on it, but it would be a better experimental.  (And I'd start using it all the time.) - [[User:Omegatron|Omegatron]] 23:10, July 28, 2005 (UTC)

:: The problem is that your browser probably won't know that it's supposed to interpret the MathML as MathML unless the server sends out some additional information. You should try splicing some of blahtex's output into a page with wikipedia's standard headers and see if that works. I suspect it won't, although I haven't tried it myself. Maybe if you save it as a file with a xhtml extension, and fiddle with the file headers then that might work, or something like that. (btw, "rudimentary" means: it can handle equations as complicated as "x+2" but not as complicated as "x^2" :-)) [[User:Dmharvey|Dmharvey]] [[User talk:Dmharvey|Talk]] 16:38, 30 July 2005 (UTC)

:::Yes, I know; I've played with it.  But if they can already get my browser to display mathML for <math>x+2</math>, and a Tex-to-mathML converter has been written, why can't they combine the two?  It sounds like the rudimentary mathML support already does all the "hard stuff" like MIME or XHTML or whatever other strings of capital letters. - [[User:Omegatron|Omegatron]] 00:48, August 4, 2005 (UTC)

::::Your browser (probably) doesn't really display the MathML for <math>x+2</math>.

::::For example, I often use Safari, which doesn't know anything about MathML. The MathML code for "x+2" is <nowiki><mi>x</mi><mo>+</mo><mn>2</mn></nowiki>. So safari just ignores the tags like <nowiki><mi></nowiki> and just prints the conents inside the tags, which turns out to look ok (i.e. looks like "x+2"). But for anything more complicated it's useless. For example to do something like "x^2" it sees <nowiki><msup><mi>x</mi><mn>2</mn></msup></nowiki> and it just prints something like "x2".

::::Now here's the thing. Even a browser like Mozilla, which knows about MathML, will just print "x2", UNLESS you put a whole bunch of headers at the beginning of the page, which Wikipedia doesn't currently do. So, although it would be very easy to simply plug blahtex into the mediawiki software to do the conversion, it would presently be useless, because no-one would be able to see the MathML output. (Unless they manually changed the headers on every page they downloaded, which is ridiculous). Until Wikipedia is able to send out the right headers, or unless there is some other way to coax everyone's browsers into interpreting the MathML, there isn't any point in just "plugging it in". [[User:Dmharvey|Dmharvey]] [[User talk:Dmharvey|Talk]] 10:55, 4 August 2005 (UTC)

:::::Aha.  Well, is it really that hard to plug in the appropriate headers?  Is it a server-side MIME kind of thing as well or is it something that could be added with a clever user.js or greasemonkey script?  If the current experimental mathML can't add the headers either, then what's the harm in plugging in the new converter? - [[User:Omegatron|Omegatron]] 17:08, August 4, 2005 (UTC)


== ''n''-th versus ''n''th ==

There are quite a few articles that use "n-th", "''n''-th", and/or "''n''th" (similarly for "''i''th", etc).  All of the literature I checked uses "''n''th" (and occasionally "''n''<sup>th</sup>"). The only justification for "-th" that I can see today is if you don't have italics available, such as in a newsgroup.  Based on the articles I've seen, I think that "''n''th" is more common in Wikipedia than "''n''-th" and "n-th", but I didn't do a formal count.  

I think the standard style should be "''n''th". [[User:Bubba73|Bubba73]] 22:14, July 28, 2005 (UTC)

I prefer ''n''th; but I could understand an editor deciding that it was unclear. A standard, but not a mandatory one? 

But then, I spent today watching the anti-Communist revert wars '''and''' the &^$%&$ AD/CE revert wars, so I'm a little more ''laissez-faire'' than usual.  [[User:Pmanderson|Septentrionalis]] 22:40, 28 July 2005 (UTC)
: I prefer ''n''-th. I guess it was my edits which brought [[User:Bubba73|Bubba73]] in here. If many people say they like ''n''th, I will obey. :) [[User:Oleg Alexandrov|Oleg Alexandrov]] 23:07, 28 July 2005 (UTC)

:''n''th IS CLEARLY THE ONLY SOLUTION AND I WILL not TOLERATE THIS POV CULTURAL IMPERIALISM CHRISTIANITY-HATING U.S.-BIASED FASCIST CONSPIRACY!!1! - [[User:Omegatron|Omegatron]]!!!11!! 23:18, July 28, 2005 (UTC)!1!!!

:Should be ''n''<sup>th</sup>.  Bit of a pain to type, but if you have to use it in a lot of places, copy and paste (or write nth and do a global change). --[[User:Trovatore|Trovatore]] 14:36, 29 July 2005 (UTC)

::Would be nice if we had a wiki shortcut for super and subscripts.  I've been using T_{E}X (=T<sub>E</sub>X) markup in my greasemonkey scripts, although that might be confusing when alongside the same thing inside math tags?
::Also things like 220+-5% becomes 220&plusmn;5%, ==> becomes &rArr;, 100degC becomes 100&deg;C, and so on. - [[User:Omegatron|Omegatron]] 16:11, July 29, 2005 (UTC)

:: My personal preference is for ''n''<sup>th</sup> too, and that is sometimes used in the literature.  However, ''n''th is much more common in the literature. 

::Another argument in favor of ''n''th is that TeX has a function "\nth{<number>}", which makes 1st, 2nd, ''n''th, etc, although it isn't implemented in WP.   Furthermore, TeX interprets "n-th" as "n - th".  Since math formulas are rendered in TeX, I think we should use ''n''th to be consistent.  [[User:Bubba73|Bubba73]] 16:08, July 29, 2005 (UTC)

I think ''n''-th is marginally easier to read. I think ''i''-th, for example, is definitely easier to read than ''i''th. I think (''n'' &minus; 1)<sup>th</sup> is not a sensible piece of notation, for example; and the sort of thing that shows we should mostly aim to be clear and readable. [[User:Charles Matthews|Charles Matthews]] 16:34, 29 July 2005 (UTC)

:Well, (''n'' &minus; 1)<sup>th</sup> is just jarring to my ear; I prefer (''n'' &minus; 1)<sup>st</sup>.  I can see the point that maybe it should be (''n'' &minus; 1)st or (''n'' &minus; 1)-st, to keep people from trying to evaluate it as an exponentiation (although the latter two choices could be, respectively, multiplication or subtraction). --[[User:Trovatore|Trovatore]] 16:39, 29 July 2005 (UTC)

::That's a good argument against ''n''<sup>th</sup>.  ''n''th and (''n'' &minus; 1)th look the best to me, so far, though it seems there's a better solution for n-1 out there somewhere. - [[User:Omegatron|Omegatron]] 16:46, July 29, 2005 (UTC)

:::But in my experience nobody (or almost nobody) actually ''says'' "en minus oneth". We say "en minus first".  Conflict between euphony and logic, perhaps--in this situation I vote for euphony. --[[User:Trovatore|Trovatore]] 16:50, 29 July 2005 (UTC)

: Quoting Charles, "I think ''n''-th is marginally easier to read. I think ''i''-th, for example, is definitely easier to read than ''i''th" (ditto for ''i'').  Readability is the reason I prefer ''n''<sup>th</sup> over ''n''th.  But ''n''th seems to be almost universal in the literature and I haven't found ''n''-th in the literature.  My feeling is that WP should be more like the literature in style than that of newsgroups and email.  [[User:Bubba73|Bubba73]] 17:50, July 30, 2005 (UTC)

== vfd ==

[[Wikipedia:Votes_for_deletion/Log/2005_July_29#Arc_Sine]] --[[User:R.Koot|R.Koot]] 14:24, 29 July 2005 (UTC)

== Law of information ==

Is this article salvagable; does it even make sense? [[Law of information]] --[[User:R.Koot|R.Koot]] 15:18, 31 July 2005 (UTC)

:I couldn't make any sense out of it. When I searched the internet I found a [http://wiki.cotch.net/index.php/Talk:There_is_a_law_of_conservation_of_information discussion] on a wiki about evolution. [[User:Markus Schmaus|Markus Schmaus]] 17:11, 31 July 2005 (UTC)

:I put it on VFD [[Wikipedia:Votes for deletion/Law of information|here]]. [[User:Samohyl Jan|Samohyl Jan]] 17:15, 31 July 2005 (UTC)