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May 1, 2012 at 8:20 answer added Marc Palm timeline score: 2
Apr 30, 2012 at 20:56 history edited user4245 CC BY-SA 3.0
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Apr 30, 2012 at 20:51 vote accept user4245
Apr 30, 2012 at 20:03 comment added Mariano Suárez-Álvarez Minor nitpick: the why part of your title does not make sense... maybe it wanted to be «What is the Bernstein center of a reductive group and why is it that?» or something along those lines.
Apr 30, 2012 at 17:58 answer added Jef timeline score: 50
Apr 28, 2012 at 14:28 history edited user4245 CC BY-SA 3.0
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Apr 27, 2012 at 22:43 comment added user4245 @Alexander: "the key sentence" is only my guess and still need to be convinced by experts. Thank you for your helpful comments.
Apr 27, 2012 at 20:12 comment added Alexander Chervov Role is apparantly the same as role of ZU(g) - it allows to parametrize irreps by some managable set of params (similar to highest weights) - center acts as scalar irreps, hopefully center is finitely generated so essentially you take values of generators z_1...z_n in V and get numbers l1...ln if these numbers are different irreps are different, most probably converse is not formally true, but "informally" true, up to some "details".
Apr 27, 2012 at 20:09 comment added Alexander Chervov I think questions "What is the original motivation to introduce it ? What role does it play in the theory of automorphic forms ?" are easy to answer from the key sentence " some analogy of "the centre of enveloping algebra"" (even without knowledge what B.'s center is :). I think: motivation is to have something analogous to ZU(g). U(g) is not good thing in p-adic case - so you want some substitute. continued...
Apr 27, 2012 at 15:28 comment added Qiaochu Yuan (Agh. Above when I say "equivalences" I mean endo-natural transformations.)
Apr 27, 2012 at 14:24 history edited user4245 CC BY-SA 3.0
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Apr 27, 2012 at 14:03 history edited user4245 CC BY-SA 3.0
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Apr 27, 2012 at 8:09 comment added Alexander Chervov Is the Berntein's center finitely generated algebra ? Is it polynomial algebra for semi-simple groups ? (These properties holds true for Z(U(g)) ).
Apr 27, 2012 at 1:12 history edited user4245 CC BY-SA 3.0
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Apr 27, 2012 at 0:58 history edited user4245 CC BY-SA 3.0
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Apr 26, 2012 at 20:23 comment added Marc Palm +1 nice question, even $GL(2)$ would be nice with some explanation, why this point of view is useful.
Apr 26, 2012 at 16:44 answer added SGP timeline score: 3
Apr 26, 2012 at 16:32 history edited user4245 CC BY-SA 3.0
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Apr 26, 2012 at 16:28 comment added user4245 @BR :Thanks for your references ! It will be nice if someone could explain this in some concrete example, say for GL(n).
Apr 26, 2012 at 16:19 comment added B R Qiaochu is correct. The Bernstein center of a $p$-adic group $G$ is the algebra of endomorphisms of the identity functor on the category of smooth representations of $G$. It can also be realized as a space of distributions. See, e.g., hazu.hr/~tadic/41-Moy-T-Howe-proc.pdf or ams.org/journals/ert/2002-006-11/S1088-4165-02-00181-4/…
Apr 26, 2012 at 16:12 comment added Qiaochu Yuan The meaning I know is that the Bernstein center of a category $C$ is the (commutative) monoid of self-equivalences of the identity functor $\text{id}_C$. If that category is $R\text{-Mod}$ then this is the center of $R$ in the usual sense. I don't know what category $C$ is meant here though.
Apr 26, 2012 at 16:06 history edited user4245
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Apr 26, 2012 at 15:21 history edited user4245
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Apr 26, 2012 at 15:08 history asked user4245 CC BY-SA 3.0