Timeline for Distance to an apartment of the affine building of GL(N)
Current License: CC BY-SA 2.5
20 events
| when toggle format | what | by | license | comment | |
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| Dec 8, 2010 at 17:33 | vote | accept | Paul Broussous | ||
| Dec 5, 2010 at 12:54 | answer | added | Jean Lecureux | timeline score: 9 | |
| Nov 22, 2010 at 14:26 | comment | added | Jean Lecureux | The sector $C$ in your second question is not well-defined. I guess you should consider the sets of all fixed points of $u$ in $A$ ; if you don't, I think you can't always choose $c$ so that $c_0=x_A$. | |
| Nov 22, 2010 at 5:41 | comment | added | Paul Broussous | P.S. Asking this question was definitely a good idea :-) | |
| Nov 22, 2010 at 5:24 | comment | added | Paul Broussous | @Marty. I thank you a lot for your hint. I didn't know that article. I'm sure it will help. | |
| Nov 21, 2010 at 4:57 | comment | added | Marty | This is a bit of a specialized research question, I think. I certainly don't know the answer off the top of my head. But perhaps the paper "Kostant Convexity for Affine Buildings" (preprint on ArXiv, now in Forum. Math.?), by P. Kitzelberger will help. I think the result on p.4 comes close to an answer to the first question, and the rest of the questions are in the same spirit as Kitzelberger's paper too. Good luck! | |
| Nov 20, 2010 at 18:28 | comment | added | Jim Humphreys | @Paul: I agree with Ben that no question is too technical for this site; but you may well be the most expert visitor here. Asking research-level questions is always a useful activity. | |
| Nov 20, 2010 at 13:20 | comment | added | Joël | I approve the idea of creating a tag for building. I think that will encourage questions to be asked. This question seems difficult since it is not a pure geometric question on building: the $x_U$ are defined group theoretically. | |
| Nov 20, 2010 at 12:57 | comment | added | Ben Webster♦ | Also, the number theory and combinatorics tags where pretty bizarre, though admittedly, this is a tough question to tag. I may get taken to task for creating a singleton tag of "buildings" but c'est la vie. | |
| Nov 20, 2010 at 12:54 | comment | added | Ben Webster♦ | @Paul- I'm not sure Jim was trying to say the question was too technical (and shame on him if he was). No question is too technical for MO, though lots of questions are too technical to have a good chance of getting an answer; it may well be you are actually the most knowledgeable current MO user on the subject of affine buildings. I guess we'll find out soon enough. | |
| Nov 20, 2010 at 12:52 | history | edited | Ben Webster♦ |
re-retagging
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| Nov 20, 2010 at 10:29 | comment | added | Paul Broussous | My first definition of $x_U$ was not correct.Indeed the vertex $x_U$ is unique but $u$ is not. | |
| Nov 20, 2010 at 10:27 | history | edited | Paul Broussous | CC BY-SA 2.5 |
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| Nov 20, 2010 at 10:25 | comment | added | Paul Broussous | @Jim. I apologize if my question is too technical. In fact in the litterature on affine buildings I have difficulties to find references for the projection to an apartment. Of course there are plenty of things on retractions (on an apartement according to a fixed chamber or a fixed sector). | |
| Nov 20, 2010 at 10:16 | history | edited | Paul Broussous | CC BY-SA 2.5 |
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| Nov 20, 2010 at 10:08 | history | edited | Paul Broussous | CC BY-SA 2.5 |
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| Nov 20, 2010 at 6:00 | comment | added | Alex B. | Romeo, the connection of the last two questions that you tagged nt-number.theory to number theory is very tangential. Maybe it's just me, but I think that your re-tagging is not helping to keep the tag-space on MO clean. | |
| Nov 20, 2010 at 5:54 | history | edited | Romeo |
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| Nov 19, 2010 at 23:45 | comment | added | Jim Humphreys | These questions seem well formulated though they may be beyond the technical range of most Math Overflow users. Since there are several questions, it would help to number them and also highlight them using the command > | |
| Nov 19, 2010 at 22:19 | history | asked | Paul Broussous | CC BY-SA 2.5 |