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5 votes
1 answer
158 views

Why do most eigenspaces of a Lie algebra automorphism have finitely many orbits?

I'm interested in understanding the following lemma, which Vogan states (Lemma 4.8) in his paper The Local Langlands Conjecture (omitting the "well-known" proof). Suppose $G$ is a complex ...
David Schwein's user avatar
9 votes
1 answer
294 views

A duality result for Coxeter groups

Short version: if $G$ is a Coxeter group and $H \subset G$ is a parabolic subgroup, both acting on a space $V$, is it true that the invariant-coinvariant algebra $(S(V)_G)^H$ has a natural bilinear ...
Pablo Zadunaisky's user avatar
3 votes
1 answer
313 views

GIT quotients and automorphisms

Let $X$ be a smooth projective variety. Then we have an exact sequence: $$0\mapsto Aut^{o}(X)\rightarrow Aut(X)\rightarrow H\mapsto 0$$ where $Aut^{o}(X)$ and $H$ are respectively the connected ...
user avatar
1 vote
0 answers
187 views

Research of a reference about $G$-linearizations of line bundles on quasi-projective schemes

I am looking for some references for the following statement: Let $G$ be a linearly reductive algebraic group acting on a quasi-projective scheme $X$, over an algebraically closed field $K$. Let $L$ ...
User3773's user avatar
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