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Timeline for What is a (generalized) BN-pair?

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Jun 28, 2012 at 7:25 comment added Marc Palm @Bugs Bunny: This was certainly a mistake. You precisely have to change the set of generators for the Coxeter group because of that fact.
Jun 28, 2012 at 7:21 history edited Marc Palm CC BY-SA 3.0
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Jun 27, 2012 at 15:23 comment added Bugs Bunny I am not sure what your magic $Z(F)$ is, doc, but I am quite sure that $Z(GL)\cdot SL$ is strictly smaller than $GL$. The determinant of a matrix in the former is always an $n$-th power!! In fact, the (Iwahori,Monomonial) define a BN-pair on this group, but not on the whole $GL$
Jun 27, 2012 at 14:35 comment added Max Horn Note that the center of a group with BN-pair always acts trivially on the associated building. So in a sense, the building theoretic part (and hence the BN-pair) only ``sees'' the original group modulo its center. So this "cheap trick" indeed seems quite sensible, I guess... Well, depending on what exactly you want to do ;).
Jun 27, 2012 at 13:10 comment added Marc Palm Note that you will have to change the set of generators for the affine Weyl group a little bit while changing form $GL(2)$ to $SL(2)$.
Jun 27, 2012 at 13:02 history edited Marc Palm CC BY-SA 3.0
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Jun 27, 2012 at 12:54 history edited Marc Palm CC BY-SA 3.0
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Jun 27, 2012 at 12:45 history answered Marc Palm CC BY-SA 3.0