Timeline for In a Banach algebra, do ab and ba have almost the same exponential spectrum?
Current License: CC BY-SA 2.5
21 events
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| Mar 5, 2016 at 21:42 | vote | accept | Malik Younsi | ||
| Feb 29, 2016 at 13:54 | comment | added | Duchamp Gérard H. E. | Can anyone say who is TJR ? | |
| Feb 29, 2016 at 10:32 | answer | added | Yemon Choi | timeline score: 5 | |
| Aug 20, 2013 at 12:52 | history | edited | Malik Younsi |
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| Apr 11, 2010 at 2:44 | comment | added | Jonas Meyer | Grobler and Raubenheimer do give some sufficient conditions. Here's a link to their paper: journals.impan.gov.pl/sm/Inf/187-3-5.html | |
| Apr 11, 2010 at 2:42 | comment | added | Jonas Meyer | Grobler and Raubenheimer discuss this in a 2008 paper called "The index for Fredholm elements in a Banach algebra via a trace". In section 4 on the exponential spectrum, they say about your problem: "Whether this is true in general for the exponential spectrum is still an open question." Last revised edition: April 7, 2008. Searching Google, MathSciNet, and the arXiv, I find no paper referencing this paper or more recently addressing the question. Perhaps this is useless, as you have clearly already looked, but it seems likely that it is still an open question. Maybe you could ask them? | |
| Apr 8, 2010 at 5:55 | comment | added | Jonas Meyer | You're welcome. Actually, I don't think there was LaTeX support back then. Of course, feel free to revert or adjust any aspects of the edits I made that you don't like. | |
| Apr 6, 2010 at 19:14 | comment | added | Malik Younsi | Thank you for the edit, I didn't know mathoverflow supported LaTeX when I asked the question. | |
| Apr 6, 2010 at 2:57 | comment | added | Jonas Meyer | I edited to add LaTeX, to merge the additional note from the closed duplicate, and to make the title (an imprecise version of) the question. (I now realize that the additional note also appears in the answer below, but I think that it will be more useful in the question.) | |
| Apr 6, 2010 at 2:04 | history | edited | Jonas Meyer | CC BY-SA 2.5 |
improved formatting and merged additional note from closed duplicate
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| Mar 28, 2010 at 6:54 | history | edited | Jonas Meyer |
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| Nov 19, 2009 at 3:07 | history | bounty ended | Malik Younsi | ||
| Nov 17, 2009 at 7:30 | history | edited | Greg Kuperberg |
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| Nov 16, 2009 at 17:03 | comment | added | Malik Younsi | So, anyone has comments / reading suggestions / ideas? | |
| Nov 12, 2009 at 1:31 | history | bounty started | Malik Younsi | ||
| Nov 3, 2009 at 6:55 | history | edited | Yemon Choi |
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| Oct 30, 2009 at 9:48 | comment | added | Yemon Choi | This probably ought to have a "functional-analysis" tag on it, if anyone with the power & inclination to bestow such is reading | |
| Oct 29, 2009 at 23:43 | comment | added | George Lowther | This sounds like a very interesting question. For an arbitrary Banach algebra, I would have thought that the answer is no. Have to think of a counterexample... | |
| Oct 26, 2009 at 15:15 | answer | added | Malik Younsi | timeline score: 5 | |
| Oct 25, 2009 at 5:48 | comment | added | Yemon Choi | question poseé par TJR, n'est ce pas? It certainly seems to be quite subtle, but perhaps my intuition is faulty. If I recall correctly, one can prove that this works when A is the Calkin algebra, by using properties of the Fredholm index. I'll have to check this though. | |
| Oct 24, 2009 at 21:39 | history | asked | Malik Younsi | CC BY-SA 2.5 |