User talk:MathMartin

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Contents 1 Edit at Periodic point 2 Hyperbolic fixed points 3 Clenshaw algorithm 4 Mathematics CotW 5 Knot span

[edit] Edit at Periodic point

You said:

Given a periodic point x with prime period t, then Φ(t,x) = Φ(t + s,x) for all s in R

Are you sure? I don't really know anything about dynamical systems, but that doesn't sound right to me. This would make Φ(a,x) = Φ(b,x) for all a and b, which means that Φ(s,x) = x for any s, which sounds far too restrictive. Staecker 19:36, 25 February 2007 (UTC)

Thanks, you are correct. I fixed my mistake. MathMartin 19:41, 25 February 2007 (UTC)

[edit] Hyperbolic fixed points

Hi, MathMartin!

I've been reading the new articles (Hartman-Grobman theorem, stable manifold theorem) that you've been writing lately, and doing my best to add references. You might want to take a look, to be sure you approve. If you have any reference information yourself, I'd be heppy to hear from you. The Hartman-Grobman name was fairly simple to track down, but the stable manifold theorem is giving me more trouble. It seems there are several of these, and the one you've written about is (I think) a result attributed to Ya. B. Pesin and D. Ruelle. Is that right? Thanks! DavidCBryant 00:11, 11 March 2007 (UTC)

Thanks for putting references in the article. I was unable to check the paper by Pesin. The paper by Ruelle seems to talk about a generalization of the basic stable manifold theorem.

I am currently working on articles connected with dynamical systems and I created Hartman-Grobman theorem, stable manifold theorem as stubs, because those articles are basic (important) theorems in the field needed for reference in other articles. The main problem with those articles is that their content is quite well known but there still do not exist canonical statements of those theorems. Especially the stable manifold theorem is giving me a headache because every author seems to proof a slightly different version of it. So basically I cannot provide solid reference for the theorems and I think in these cases it is neither possible nor useful. Dynamical systems is a very confusing topic because the terminology in the field is not yet standarized and before you can state any sort of interesting theorem, you first have to fix a notation.

On the other hand adding a reference to the first paper, the theorem was published in, is a very good idea and I would very much like to see wikipedia add original (historical) statements of important theorems to math articles.

I have been following your discussion at Wikipedia talk:WikiProject Mathematics about this topic and I understand that in order to increase the quality of the articles and fend of cranks we need references. But I think in this case it is not possible and at least I did not find any canonical and easy to understand version of the theorems on the net or in books. I must admit though that I am currently studying these topics so perhaps the wikipedia dynamical system expert(s) might disagree. MathMartin 14:59, 11 March 2007 (UTC)

[edit] Clenshaw algorithm

Hi there! I just came across Clenshaw algorithm which you wrote a while back. I wonder if you know of a good algorithm for finding Chebyshev coefficients for a given polynomial? I'd be interested to expand the Clenshaw algorithm page...could you point me to a good resource for finding materials about the algorithm? --HappyCamper 17:04, 10 May 2007 (UTC)

I have written the article quite some time ago (2 1/2 years) and I am not very deep into numerical analysis at the moment. Feel free to expand the article but I cannot provide any help. All the information I have on the Clenshaw algorithm is in the article :). You could ask User:Jitse Niesen for help, as he works in numerical analysis, or post a request at Wikipedia_talk:WikiProject_Mathematics, where the mathematicians hang out. Greetings. MathMartin 17:30, 10 May 2007 (UTC)

OK, I just might do that. Thanks for getting back to me! --HappyCamper 19:09, 10 May 2007 (UTC)

[edit] Mathematics CotW

Hey Martin, I am writing you to let you know that the Mathematics Collaboration of the week(soon to "of the month") is getting an overhaul of sorts and I would encourage you to participate in whatever way you can, i.e. nominate an article, contribute to an article, or sign up to be part of the project. Any help would be greatly appreciated, thanks--Cronholm144 23:18, 13 May 2007 (UTC)

[edit] Knot span

Another editor has added the "{{prod}}" template to the article Knot span, suggesting that it be deleted according to the proposed deletion process. All contributions are appreciated, but the editor doesn't believe it satisfies Wikipedia's criteria for inclusion, and has explained why in the article (see also Wikipedia:What Wikipedia is not and Wikipedia:Notability). Please either work to improve the article if the topic is worthy of inclusion in Wikipedia or discuss the relevant issues at its talk page. If you remove the {{prod}} template, the article will not be deleted, but note that it may still be sent to Wikipedia:Articles for deletion, where it may be deleted if consensus to delete is reached. BJBot (talk) 05:16, 25 January 2008 (UTC)