User talk:R.e.b./Archive 3

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Zariski surface

Hello. Have you noticed the discussion at Wikipedia:Articles for deletion/Zariski surface? It is proposed that this article be deleted because a now-banned user, Piotr Blass, was its original author. But he was not its original author; you were. (It makes no sense to me at all to consider that a reason to delete an article. Some say his edits to it were in some ways an abuse of Wikipedia editing privileges. But if he's banned, there's no danger of that, so that cannot be a reason to delete it, IMO.) (It does not appear that it will be deleted, however.) Michael Hardy 02:44, 22 January 2007 (UTC)

"Zariski surface" is an obscure and rather pointless topic that only barely passes the guidelines for notability. Charles Matthews added a redlink about them to Enriques-Kodaira classification, which surprised me as I'd never heard of them; after looking them up, I wrote a short note about them mainly to save anyone else from wasting time trying to find out what they were.

Blass's edits to the article are mostly harmless, though they need a lot of copy editing. (On the other hand they don't add much useful for general readers: if everything except the introduction and the reference to Zariski's paper were deleted, it would be no great loss.) The bans and blocks on him are an overreaction: he is (mostly) trying to help and is gradually improving, but is rather slow at understanding how wikipedia works. R.e.b. 04:05, 22 January 2007 (UTC)

Unfortunately for him: we are tightening up on autobiographical editing; and his way of appealing the ban is upper-case only, little coherence and less punctuation. Charles Matthews 16:39, 22 January 2007 (UTC)

That's a good reason for protecting his vanity page from re-creation, but if it is protected then blocking him seems unnecessary. (Though it does save time!) R.e.b. 17:08, 22 January 2007 (UTC)

geometrization theorem

Geometrization theorem is actually a common name for Thurston's geometrization theorem for Haken 3-manifolds. Nobody actually calls the geometrization conjecture "geometrization theorem". I don't know if you were aware of this; I don't think many people outside the subject do, so this ought to be straightened out somehow. I think the geometrization theorem is of sufficient importance for its own article, with the appropriate link from geometrization conjecture. --C S (Talk) 01:08, 28 January 2007 (UTC)

The geometrization theorem is a special case of the geometrization conjecture, so a redirect seems fine until someone writes a separate article. R.e.b. 01:31, 28 January 2007 (UTC)

I've just added the "R with possibilities" template to that redirect page. Michael Hardy 01:39, 28 January 2007 (UTC)

Elementary proof

Do you have a citation that the distinction between elementary and non-elementary is precisely whether it is doable in Peano arithmetic? I don't think that's correct in that even Selberg's proof uses a small bit of real analysis and it isn't at all obvious to me that it can be converted to a proof that is completely in Peano arithmetic. JoshuaZ 03:20, 6 February 2007 (UTC)

My recollection was that Selberg in his paper carefully eliminated all real analysis. But on rechecking it at [1] I find that he says that he eliminates all real analysis except for the most elementary properties of the logarithm. These can be converted into Peano arithmetic in a standard way by replacing the logarithms with harmonic sums. So Selberg's proof can indeed be converted into a proof in Peano arithmetic, though verifying this not completely trivial. R.e.b. 03:42, 6 February 2007 (UTC)

Abhyankar's conjecture and Abhyankar's lemma

Thanks for clearing up the confusion over Abhyankar's conjecture, and for creating the article on Abhyankar's lemma. DFH 19:45, 12 February 2007 (UTC)

AdS space

Please see the discussion page about AdS space. Pierreback 16:26, 28 February 2007 (UTC)

RE: Notation for groups

Hi R.e.b

IMO the notation GL(n,•) is not outdated nor mathematically inferior to GL_n(•) (it is a functor this way too, like Hom(M,•) ). There is not much difference between the two but I think we should avoid subscripts and superscripts if we can, hence in this context I think GL(n,•) is better. —Preceding unsigned comment added by Hesam7 (talk • contribs)

Missing Unsolved Problem Box

R.e.b., why did you remove the unsolved problem box in the resolution of singularities article? Giftlite 17:08, 16 March 2007 (UTC)

Because it just duplicated a sentence already in the introduction. R.e.b. 17:54, 16 March 2007 (UTC)

Then, if you don't mind, I'd like to add Category:Unsolved problems in mathematics to the article. Giftlite 18:02, 16 March 2007 (UTC)

That sounds like a much better idea. Categories dont clutter up an article in the way that navigation boxes do, and are easier to use. R.e.b. 18:45, 16 March 2007 (UTC)

E8 story

What exactly have they computed for poor old E8 (mathematics)? Is it some structure matrix for the representation ring? Breaking news, but the press stuff has all the vital words taken out!

Charles Matthews 22:34, 19 March 2007 (UTC)

Kazhdan-Lusztig-Vogan polynomials for the split real form of E₈ according to this. I'll wait until the fuss has died down before trying to clean up the article. R.e.b. 22:43, 19 March 2007 (UTC)

Yes, also here.[2] Charles Matthews 22:56, 19 March 2007 (UTC)

Kazhdan-Lusztig polynomials, Hecke algebras

Hi there, I've reverted some of your recent edits to these articles. Please, do not take it personally, but it seems that some of your contributions are a bit hasty, and sometimes introduce errors. For example, you've added references to Iwahori-Matsumoto, which is fine, but in the wrong place (for finite case instead of affine). Likewise, it may be argued what the true motivations of Kazhdan and Lusztig were, but they very explicitly state that their polynomials measure "failure of local Poincare duality", which is understood to be the non-vanishing of local intersection cohomology of Schubert varieties. I also feel that an encyclopedia is not a proper venue for fleshing out technical details; instead, we need to state the general picture as seen by experts. I would be interested to know your opinion on this. Best wishes, Arcfrk 02:52, 26 March 2007 (UTC)

I did indeed misremember which case Iwahori-Matsumoto did. On the other hand my comments about K and L's motivation that you removed were more or less copied directly from their first paper. I'm a little surprised that they make no mention of IH there if that really was their original motivation. But it's not important enough to spend further time on.

Please don't remove www links to papers that are used as references: they make it much easier to fix misprints, such as the ones in the original version of that section. R.e.b. 03:44, 26 March 2007 (UTC)

OK. Please, also take a look at my comments in Talk:Hecke algebra. Arcfrk 04:53, 26 March 2007 (UTC)

Hello again, in the article on Kazhdan-Lusztig polynomials you wrote

As of 2007, there is no known combinatorial interpretation of the coefficients of the Kazhdan-Lusztig polynomials (as the cardinalities of some natural sets) even in the case of the symmetric groups.

Are you sure that that's true? First, there are definitely formulas for Kazhdan-Lusztig polynomials in some cases, like Lascoux-Schützenberger formulas for Grassmanians, Lusztig's intertpretaion of certain affine Kazhdan-Lusztig polynomials in terms of q-weight multiplicities, etc. One of my goals in creating this subsection had been to expose some of the results from Section 6.3 of Billey-Lakshmibai, especially Deodhar's theorem, I just have not gotten around to that yet. From my perspective, it would not have made too much sense to say "there is combinatorial theory" in the article if there had not been combinatoriral formulas. And also, there was big progress made recently in related questions, this is not a topic for a discussion on Wikipedia, but I would cautiously only vouch for as of June 2006, there was no general bijective formula for KL polynomials for all y,w in the symmetric group. In view of the comments above (some nice formulas exist), however, I do not think such a negative statement should be included in this section. Arcfrk 03:25, 29 March 2007 (UTC)

I'm not absolutely sure; but I saw it mentioned somewhere in a recent publication (Bjorner and Brenti?) as an important and hard unsolved problem. Feel free to update it if you have more recent info about its status (or go ahead and tone it down or delete it if it really upsets you). R.e.b. 03:41, 29 March 2007 (UTC)

Macdonald polynomials and Hodge structures

Hi R.e.b., the page on Macdonald polynomials looks very nice. Good job! Arcfrk 14:53, 1 April 2007 (UTC)

I've glanced at Hodge structure, it looks fairly complete as it is. Even though I am not by any means an expert in this, I've added a bit of intuition-applications, please, let me know if this type of material is helpful/appropriate for Wikipedia. Arcfrk 05:45, 6 April 2007 (UTC)

I think its helpful and appropriate for Wikipedia. (Though my views on what should be in wikipedia are somewhat non-standard.) I'm not expert in this area either, so its probably a good idea for more than 1 person to contribute to it. R.e.b. 18:17, 6 April 2007 (UTC)

I've made fairly substantial changes to Hodge structure, it's probably not the end of story, but can you, please, let me know your opinion so far? Arcfrk 07:46, 21 April 2007 (UTC)

Adding more than the bare definitions is a big improvement. R.e.b. 13:10, 21 April 2007 (UTC)

E8 lattice

If you're curious, I've just started a new article on the E8 lattice. Comments, criticisms, and contributions are more than welcome. I'm sure you know much more about this stuff than I do. -- Fropuff 19:36, 20 April 2007 (UTC)

The article looks great as it is; I cant offhand think of anything important to add to it. R.e.b. 21:12, 20 April 2007 (UTC)

Great! Thanks for looking at it. -- Fropuff 04:53, 21 April 2007 (UTC)

Picture request at Fields_Medal

Hi. I believe you may be able to help out with this request, if it's not too much of a bother. --C S (Talk) 06:11, 30 April 2007 (UTC)

Dihedral groups

OK, I will go with the notation you want. I notice that Joseph Rotman conceded the point in the 4th edition of his group theory text. Scott Tillinghast, Houston TX 03:15, 1 May 2007 (UTC)

re Jeffrey Adams (mathematician)

This person appears not to pass the WP:PROF test, at least as the article is presently formed. Herostratus 15:03, 12 May 2007 (UTC)

As I wrote on User talk:Herostratus, the article does not fall under one of the criteria of speedy deletion. I thus restored the article. -- Jitse Niesen (talk) 15:32, 12 May 2007 (UTC)

Thanks. But the article still seems to be deleted several hours after you restored it. R.e.b. 19:42, 12 May 2007 (UTC)

... and now I've restored it, and stated on the talk page why speedy deletion was not appropriate, and contacted the user who marked it for speedy deletion. Michael Hardy 22:26, 12 May 2007 (UTC)

Thanks; looks like the trouble was caused by a couple of well meaning high school kids. As usual. R.e.b. 22:45, 12 May 2007 (UTC)

Well, I now see that it was deleted twice. I didn't notice that they were high school students, and the user page of one of them makes it look as if he's not just having fun putting idiotic graffiti into things. Michael Hardy 22:59, 12 May 2007 (UTC)

Silly me forgot to remove the "speedy deletion" tag when I restored the article. Thus, it was deleted again soon after I restored it. -- Jitse Niesen (talk) 03:18, 13 May 2007 (UTC)

Tempered representations

Hello again, and thanks for the tip on how to avoid edit conflicts! I am a little uneasy about your recent edits of tempered representation. The concerns are two-fold: factual and expository. Which sources are you using for that article? I do not have Knapp, Wallach or Borel-Wallach close at hand, but usually tempered representations are defined in terms of the rate of growth of their matrix coefficients, not of their Harish-Chandra character, which is a highly non-trivial generalization of a character of a representation of a finite group. Likewise, in Harish-Chandra's work, the fact that the matrix coefficients of tempered representations belong to L^2+ε(G) comes after a fair amount of work, since a priori it's unclear that this would be a good condition, and in particular, that this property holds for the matrix coefficients of the (spherical) unitary principal series. The converse is also a non-trivial fact, since the 2+ε growth rate is a 'softer' condition than the what you get from an explicit comparison with the $\Xi$-function. Even if someone does define temperedness in terms of the Harish-Chandra character, we should really give the definition in terms of the matrix coefficients. Firstly, it explicitly occurs in most of the literature, and secondly, it does not rely on rather non-trivial theory of the Harish-Chandra character (note, by the way, that it is still a red link). Of course, in Properties it can be mentioned that the three conditions on an irreducible admissible representation of a real reductive Lie group are equivalent: one K-finite matrix coefficient is asymptotically bounded by the $\Xi$-function, the same holds for all K-finite matrix coefficients, and finally, the Harish-Chandra character satisfies the growth estimate, making it a tempered distribution. The same should also be true for semisimple p-adic groups (I can't find it in Harish-Chandra; cf. Silberger's book, which I also don't have).

I do not want to make changes myself, for a couple of reasons. Firstly, you seem to be working rather actively on that article, and also, I do not have any of the standard references and having already made one rather questionable substitution (I've put locally compact group in the beginning, since the L^2+ε condition is meaningful in this generality, although I can't recall if anyone refers to representations of non-reductive groups with this property as 'tempered'), I'd rather not introduce any more hastily made statements. Arcfrk 04:11, 13 May 2007 (UTC)

I replied at Talk:Tempered representation.R.e.b. 13:34, 13 May 2007 (UTC)

capable group

Someone proposed deletion of the article titled capable group. Perhaps your opinion could shed some light. Michael Hardy 00:10, 25 May 2007 (UTC)

I've never heard of this concept. It seems useless but harmless. R.e.b. 00:27, 25 May 2007 (UTC)

Now I've looked at Google Scholar and I find some relatively recent research, including papers that begin by asking the reader to "recall" the definition of this concept. I've edited the article to indicate only the oldest one, published in 1938. I'll leave it to people who know some group theory to decide which of those published in the 21st century to include. Michael Hardy 00:58, 25 May 2007 (UTC)

Capable groups are an important research area in group theory, especially in nilpotent groups. To build a nilpotent group from its upper central series is nice, but most groups are not parents in this way. A similar concept with an identical name refers to quotients by the last term of the lower exponent-p central series and is fundamental to the study of small p-groups. Glancing at MathSciNet shows that I.M. Isaacs, H. Heineken, J. Wiegold, and R. Baer have published on this topic, any one of which should justify the article. JackSchmidt 21:06, 5 July 2007 (UTC)

Frobenius Group

A fair number of changes have been made to Frobenius group, and in the next few days I was going to add back in some reverted material in a new section. I just wanted to make sure I hadn't overlooked anything since the revert wasn't explained. I assume that basically the new text was awful and so you turned it back into something nice. I plan on including the information in a much nicer way with better context and references, so don't foresee any objections. However, the edit log mentioned the definition being incorrect, so I wanted to check first. Oh, and if you care I commented on capable groups in your older talk page. They are quite important to some of us :) JackSchmidt 21:11, 5 July 2007 (UTC)

The definition of Frobenius group was indeed wrong, though not seriously: it omitted the condition that the subgroup H is non-trivial. The main problem was not that the definition was slightly wrong, but that it was unintuitive and unmotivated.R.e.b. 03:14, 6 July 2007 (UTC)

RS1900

Are you Richard Borcherds? Well, sir, I am RS1900. In future I will created article related to physics and mathematics. Can you help me? Thank you. RS1900 06:34, 18 September 2007 (UTC)

If you want to edit math articles you might find the pages Wikipedia_talk:WikiProject_Mathematics and Wikipedia:WikiProject_Mathematics useful. R.e.b. 14:57, 18 September 2007 (UTC)

...and also Wikipedia:Manual of Style (mathematics). Michael Hardy 18:05, 18 September 2007 (UTC)

You have not answered my question. Anyway, I am mainly interested in Physics. Thanks for the reply. All the best. RS1900 02:45, 19 September 2007 (UTC)

I will not ask any personal questions. I looked at your edits and you two are very interesting individuals. All the best. RS1900 02:50, 19 September 2007 (UTC)

Names

Greetings. In the von Neumann algebra article I find some parts of the introduction a little bit too direct now. I wonder if you could possibly change this please? Mathsci 18:57, 23 September 2007 (UTC)

Could you be more explicit? I have no idea what you mean. R.e.b. 19:04, 23 September 2007 (UTC)

I very slightly changed your format. There are other texts (eg Bratteli and Robinson I, Stratila and Zsido, Pedersen, Kadison and Ringrose) which could be added, but that's a matter of taste. Mathsci 20:45, 23 September 2007 (UTC)

The books listed are just those I happen to be familiar with; if you know other good ones go ahead and list them. They were added to satisfy the Wikipedia:Scientific citation guidelines.R.e.b. 21:10, 23 September 2007 (UTC)

proof of Minkowski inequality

Hi R.e.b.,

I've made a comment on the proof of the Minkowski inequality that you added on its talk page. --MarSch 14:02, 1 October 2007 (UTC)

Speedy deletion of George W. Whitehead

A tag has been placed on George W. Whitehead, requesting that it be speedily deleted from Wikipedia per CSD A7.

Under the criteria for speedy deletion, articles that do not meet basic Wikipedia criteria may be deleted at any time. Please see the guidelines for what is generally accepted as an appropriate article, and if you can indicate why the subject of this article is appropriate, you may contest the tagging. To do this, add {{hangon}} on the top of the article and leave a note on the article's talk page explaining your position. Please do not remove the speedy deletion tag yourself, but don't hesitate to add information to the article that would confirm its subject's notability under the guidelines.

If you think that this notice was placed here in error, you may contest the deletion. To do this, add {{hangon}} on the top of the page (just below the existing speedy deletion or "db" tag) and leave a note on the page's talk page explaining your position. Please do not remove the speedy deletion tag yourself. Rackabello 23:30, 8 October 2007 (UTC)

Diffeomorphism

Happy Guy Fawkes day. I have added some material to this article and I wondered whether you could look over it for omissions, errors, etc. There are still references to add, like the asterique Travaux de Thurston sur les surfaces. I have made the wikilinks with exotic spheres. Thanks for adding the Spanier BLP. --Mathsci 16:44, 5 November 2007 (UTC)

I didnt see any obvious problems; the article seems fine. R.e.b. 17:05, 5 November 2007 (UTC)

Proof-theoretic ordinals for large cardinal axioms

Hi R.e.b.,

I have never heard that anyone has succeeded in isolating such a thing. As far as I know the study of proof-theoretic ordinals is bogged down somewhere around second-order arithmetic. Are you referring maybe to some abstract result, one that doesn't give a clear picture of the ordinals involved? If so, what result are you referring to? --Trovatore 18:38, 11 November 2007 (UTC)

Depends what you mean by "isolate such a thing". You can always give explicit computable descriptions of such ordinals in the sense that you can (with a lot of patience) write down an explicit Turing machine that computes such a well ordering on a r.e. subset of the natural numbers, though I guess it would be fair to say this does not give a clear picture of the ordinal. If you want a "combinatorial" description, then as you say no one seems to have gotten past weak fragments of second order arithmetic. R.e.b. 18:54, 11 November 2007 (UTC)

On second thoughts, I'm not sure that the ordering you can compute is a well ordering; it might be a well ordered quasi order or something like that. But it is essentially equivalent in strength to the proof theoretic ordinal. R.e.b. 19:04, 11 November 2007 (UTC)

Well, so if all there is here is that you can reduce consistency claims to claims of the form "such-and-such a putative ordinal notation gives rise to a wellfounded tree of ordinal notations", then I think it's a bit misleading to mention the proof-theoretic ordinals at list of large cardinal properties. I mean, that's hardly a surprising result; consistency claims are $\Pi _{1}^{0}$ whereas Kleene's O is $\Pi _{1}^{1}$-complete. It would be a bit more interesting if the result were about the actual ordinal, but as you've described it it seems to be more about the ordinal notation.

Here's a test question: As far as I know, for any two large-cardinal axioms, either they are equiconsistent, or one of them proves the existence of a wellfounded model of the other one. Is there any case you know of where there's anything you want to say about their proof-theoretic ordinals, that doesn't follow directly from that? If not, I think we should probably remove the proof-theoretic ordinals from the discussion. --Trovatore 19:18, 11 November 2007 (UTC)

If you could prove that for any two large-cardinal axioms, either they are equiconsistent, or one of them proves the existence of a wellfounded model of the other one, then this would indeed imply the results you get from considering proof theoretic ordinals. However this result is not yet known in all cases: for example it is not currently known if one of superstrong and strongly compact implies consistency of the other. However it is obvious that their proof theoretic ordinals are comparable. In other words proof theoretic ordinals explain why large cardinal properties can be linearly ordered; consistency strength does not. R.e.b. 19:30, 11 November 2007 (UTC)

Well, it's not actually the kind of thing that's subject to proof, because there isn't a generally accepted abstract definition of "large-cardinal axiom". Woodin has one but not everyone buys it. It's an observation, one of the things that shows that mathematics is an empirical science and not purely logic. My philosophical slant coming in there, obviously.

But let's dig deeper into this stuff about the proof-theoretic ordinals; maybe you can educate me here. But I want to make sure you're not conflating the ordinals themselves -- which are obviously linearly ordered -- with the notations that represent them, where it's not so clear. Why can't it be the case that you have notations N1 and N2, such that ZFC proves neither the proposition "if N1 is a (wellfounded) ordinal notation then so is N2", nor the converse? --Trovatore 19:43, 11 November 2007 (UTC)

It's not clear (to me) that it can't be the case. That's why it says in the article:"(It is conceivable that this order depends on which model of ZF one is working in, though no cases of this are known.)".

So then basically I don't see what the proof-theoretic ordinal stuff adds to the discussion. We know that there are theories that have incomparable consistency strength. The remarkable fact, still not fully explained (though Woodin has an attempt), is that this never appears to happen for theories of the form "ZFC+large-cardinal axiom". If proof-theoretic ordinals did explain it, then that would certainly be worthy of noting, but I don't see that they do.

As it stands I think the text is misleading. Unless there is some actual work in the literature treating these ordinals, I think we should just remove it. --Trovatore 20:47, 11 November 2007 (UTC)

The point is that the proof-theoretic ordinal stuff gives an informal explanation of why large cardinal properties seem to have a natural linear order. R.e.b. 21:04, 11 November 2007 (UTC)

But it doesn't give such an explanation, even informal, unless there's more to it than you're telling me. Which could well be; I don't know that much about proof-theoretic ordinals.

Let me put it this way: consider two theories T1 and T2 with incomparable consistency strengths. Do they have proof-theoretic ordinals, in the sense you intend here? If they don't, then the question becomes "why do theories of the form ZFC+large cardinals have proof-theoretic ordinals, when not all theories have them?". Whereas if they do, then the question becomes "why do consistency strengths of theories of the form ZFC+large cardinals line up with their proof-theoretic ordinals, when this is not true of all theories?". Either way, as far as I can tell, it just shifts the problem one step; I don't see that it explains anything.

As a side question, maybe you could say a little more about what a "proof-theoretic ordinal" is in general. I know the example of PA and epsilon-naught and the Gentzen proof, but I'm not sure how it generalizes. I can easily cook up an ordinal notation for the ordinal zero, such that the notation is wellfounded if and only if ZFC+"there exists a measurable" is consistent, but you wouldn't express that consistency result as equivalent to "zero is wellfounded". So I suppose for an ordinal α to be a proof-theoretic ordinal for T, you want that, given any notation for α, the wellfoundedness of that notation implies Con(T). And by analogy with the Gentzen thing, you'd also hope that for at least some notation for α, Con(T) implies the wellfoundedness of that notation. Is that a good criterion for being a proof-theoretic ordinal for T? And if so, is it actually known that any theories of the form ZFC+LCA even have proof-theoretic ordinals? --Trovatore 21:29, 11 November 2007 (UTC)

You can assign a proof-theoretic ordinal to pretty much any theory powerful enough to describe Turing machines. (The theory doesnt have to be about large cardinals; in fact a few of the entries, such as zero sharp, zero dagger, and Vopenka's principle, are not large cardinal axioms.) You can define it as the smallest constructible ordinal that the theory cannot prove is well ordered, which is probably more or less equivalent to your definition. In practice, as you suggest, a converse is often true, so the consistency of the theory is equivalent to the well ordering of its ordinal, and if this happens then the ordering by proof theoretic ordinals is the same as ordering by consistency. There is a subtle problem about whether the ordering of constructible ordinals depends on on the model of ZF you use, which I will not discuss as it gives me a headache. I also have a suspicion that everything should be really formulated in terms of constructible quasi well orderings rather than constructible well orderings. R.e.b. 22:08, 11 November 2007 (UTC)

OK, so I still wish you'd be more careful about distinguishing between ordinals and their notations (which I think would ameliorate your "subtle problem" with models of ZF) but basically this is along the lines of what I was saying -- the question boils down to whether there's a two-way result, with Con(T) proving wellfoundedness of some notation for the ordinal, but where the wellfoundedness of even one notation for the ordinal proves Con(T). Is that correct?

If so, are there any results showing that there's such a two-way result for some theory of the form ZFC+LCA? Not necessarily all known such theories, but even one such theory? Because otherwise I really think the discussion should be removed -- as I say, it doesn't explain anything, even informally, but just suggests that if these theories had ordinals with this two-way property, then that would imply the observed linearity. --Trovatore 22:23, 11 November 2007 (UTC)

This seems to be turning into an extended tutorial on proof theoretic ordinals. It might be more efficient to learn about them by reading a book. R.e.b. 22:36, 11 November 2007 (UTC)

Perhaps, but the goal is to figure out whether the text belongs there or not. Right now I don't think it does. Surely it ought to be clear from the text plus references why it belongs, if in fact it does. --Trovatore 22:40, 11 November 2007 (UTC)

Cauchy-Kowalevski theorem

The Hormander reference only treats the linear case, so is not so useful. Mathsci 20:36, 13 November 2007 (UTC)

If it's good enough for Hormander, it's good enough for me. Do you have any idea why Ko*ale*sk* spells her name with a "y" in her paper on the C-K theorem? (I suspect it's a misprint by the german printer, who seemed to think her middle v stands for von!) R.e.b. 22:24, 13 November 2007 (UTC)

logical foundations of scientific math

With probability 1-ε for some small ε, you've already seen this; but just in case, it might interest you:

S. Feferman, Why a little bit goes a long way: Logical foundations of scientifically applicable mathematics 75.62.4.229 (talk) 09:40, 22 November 2007 (UTC)

Thanks; I didnt know about it but it's quite interesting. R.e.b. (talk) 14:58, 22 November 2007 (UTC)

harvnb

I think the problem was because there were two authors. If I remove Dan Segal, all is well with "citation". Otherwise not. I will experiment. Mathsci (talk) 19:15, 25 November 2007 (UTC)

That was it. Segal had to be added to harvnb to make it work. Mathsci (talk) 19:17, 25 November 2007 (UTC)

Srinivasa Ramanujan

Thanks for this edit. See my changes. I saw you had changed the expression with pi, so I changed it back to the version before. I just realized that maybe that was your intention in the first place. Is this the case? If it is, I'll undo my edit. Best, Nishkid64 (talk) 04:51, 2 December 2007 (UTC)

Yes, my change to pi was intentional, so you can revert back to my version. R.e.b. 04:54, 2 December 2007 (UTC)

Okay, I added it back. Ramsey2006 confirmed that it was divergent, then the integral would just go to infinity or negative infinity. Have your changes fixed this problem now? Is it now convergent? Nishkid64 (talk) 05:13, 2 December 2007 (UTC)

Yes, the integral is now correct and convergent, at least for 0<a<b+1/2, unless I've missed something. R.e.b. 05:15, 2 December 2007 (UTC)

Ramanujam

You wrote:

C P Ramanujam needs to be moved to C. P. Ramanujam, but this seems to need admin tools to do while keeping its history, as the latter article already exists as a stub. (I think the stub can be quietly deleted; I wrote most of it anyway.)

Hello. If I were not somewhat confused about how to merge the edit histories of two articles, I'd have attended to this right away. And if I'd noticed that you said the stub could just be deleted, I'd also have attended to it right away; that one's easy. I see someone's done it now. Michael Hardy (talk) 14:56, 17 December 2007 (UTC)

...OK, now I see that that was actually a cut-and-paste move. I restored the old version of C P Ramanujam, before it was made a redirect, then I moved it, in the process deleting the target article and its history. If substantial changes were done after the cut-and-paste move, then we should probably recruit someone who knows how to merge edit histories. Sorry not to get to this sooner. Michael Hardy (talk) 15:03, 17 December 2007 (UTC)

Thanks; you seem to have sorted out a rather confusing mess! R.e.b. (talk) 15:36, 17 December 2007 (UTC)

If there were edits AFTER the copy-and-paste move, then probably the people who did those edits should be notified so that they will know that the deletion was not intended to wipe out their edits, and so that they can reinstate them and have their names in the edit history. In order to do that, it is necessary to find out which ones those are. That requires looking at the edit history of the now-deleted article, below. Would I be right in guessing that it's ONLY "Hemaraman"? Michael Hardy (talk) 20:13, 17 December 2007 (UTC)

history of C. P. Ramanujam

1. 14:57, 17 December 2007 (diff) . . Michael Hardy (Talk

The edits by Hemaraman were a (well-meant but somewhat confused) attempt to merge the articles, and the only person who edited after this seems to be you. None of the other people in the edit history added anything important to my initial stub so I dont think losing this old edit history matters much. Maybe the talk page should have a comment explaining what you did just in case someone gets confused. Otherwise everything now seems fine. R.e.b. (talk) 20:39, 17 December 2007 (UTC)

Style note

Hi Reb. Thank you for your work at Radon measure. I have one note. At least to me, having text of the form "Warning" in the text looks overly formal and not encyclopedic. I sort of preferred the original way of saying things, "following Bourbaki", etc. I wonder what you think. You can reply here. Thanks. Oleg Alexandrov (talk) 20:44, 23 December 2007 (UTC)

Unfortunately the "original way of saying things" was wrong and misstated Bourbaki's (extremely confusing and non-standard) terminology. It also changed definitions in the middle of the article, which did not seem a good idea. If you want to change "Warning" to something less formal go ahead. R.e.b. (talk) 21:09, 23 December 2007 (UTC)

I won't change the wording, since I know little about those things. I just thought I'd comment on your talk page about the style thing. Of course, what's most important is that the content be correct. Oleg Alexandrov (talk) 22:27, 23 December 2007 (UTC)