# Stephen Griffeth

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bio website mathoverflow.net location age member for 3 years, 10 months seen Apr 12 at 23:45 profile views 307

# 68 Actions

 Jan5 awarded Revival Jan5 awarded Necromancer Jan5 awarded Yearling Jan5 awarded Nice Answer Sep8 awarded Enthusiast Aug28 revised Are linear algebraic groups rigid? deleted 7 characters in body Aug28 comment Are linear algebraic groups rigid? Nice! It's never a bad idea to read SGA. Do you know if it is possible to see this deformation as a commutative deformation living within a larger family also containing quantum $\mathfrak{sl}_2$? Aug28 awarded Citizen Patrol Aug28 comment Are linear algebraic groups rigid? @user54268 So, you are saying that reductive groups are rigid, yes? Aug28 comment Are linear algebraic groups rigid? @Tony Pantev Huh. I guess I just wrote down this. For some reason your comment didn't show up while I was writing my answer... Aug28 answered Are linear algebraic groups rigid? Aug26 comment Representations of parabolic subgroups of the general linear group over the complex numbers It depends on what you mean by "easy", I think. Any semisimple representation of $B$ will of course be a direct sum of one dimensional subrepresentations. But arbitrary representations need not be. Aug16 comment Update on list of open problems for Cherednik/Symplectic Reflection Algebras OK, thanks! I should edit the answer a bit when I have some time, and among other thigns I'll fix that. Aug15 comment Update on list of open problems for Cherednik/Symplectic Reflection Algebras @BenWebster Perhaps I should have written "crystal combinatorics" instead of "KL combinatorics"? I would be interested to know if it's possible to recover Pavel Etingof's classification of when $L_c(\mathrm{triv})$ is finite dimensional for $G(2,1,n)$ from what Roman and Ivan did (or from what Ivan has done since). Aug14 comment Update on list of open problems for Cherednik/Symplectic Reflection Algebras Well, ok, when is the trivial lowest weight irreducible finite dimensional? It's my impression from talking to Ivan that even this question is not so easy to answer. It would be interesting for me, at least, to know if the set of parameters for which it is can have components of codimension more than two in the parameter space! Aug14 answered Update on list of open problems for Cherednik/Symplectic Reflection Algebras Jun2 comment If $M$ has hyper-kaehler structure then $M//G$ has hyper-kaehler structure? I don't understand your comment---(1) which Peter? and (2) Neither one wrote exactly what you did, as far as I can tell. It seems to me that Peter Crooks is incorrect in asserting that his response addresses your A) above. Jun2 comment If $M$ has hyper-kaehler structure then $M//G$ has hyper-kaehler structure? @HassanJolany Projective spaces are all Kahler (with the Fubini-Study metric), no? I suppose that in this example it should be the same as that produced by Thm 3.1 of HKLR. May27 comment Why are there no triple affine Hecke algebras? Nice! I suppose the moral for me is, using Ext algebras instead of End provides an extra lattice (or polynomial ring). Is it right that without doing the mixed version you just get something like a semidirect product of the Weyl group with a commutative ring? May26 answered Why are there no triple affine Hecke algebras?