Alexander Braverman

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visits member for 4 years, 2 months
seen Apr 12 at 8:36

Apr
8
answered What is the intuition behind the definition of cuspidal representations?
Apr
3
accepted An affine singular surface
Apr
2
comment An affine singular surface
Yes, I understand, but I wonder if someone has already performed that.
Apr
2
asked An affine singular surface
Feb
8
awarded  Yearling
Nov
18
comment Restriction to Levi Subgroups and the Affine Grassmannian
Let me make one comment about it. Although, the construction is indeed as described above, there is one subtle thing about it. Namely, on the representation theory side, the restriction functor depends only on $L$ but not a choice of a parabolic $P$. However, geometrically the functor depends on the parabolic very heavily (note that you can have non-conjugate parabolics with the same Levi). I don't know any geometric way (without using Satake equivalence) to prove independence of $P$ - this is actually a very good problem (but probably it has no reasonable solution).
Nov
18
accepted Kawamata-Viehweg vanishing for non-Gorenstein singularities
Nov
18
comment Kawamata-Viehweg vanishing for non-Gorenstein singularities
Thanks a lot, Sandor (and Dave). I think that log canonicity will suffice for my situation. And I promise to improve my notation! (you are definitely absolutely right about it).
Nov
17
comment Kawamata-Viehweg vanishing for non-Gorenstein singularities
Thank you. But I really need something more similar to my original question. The point is that I need to prove cohomology vanishing for some line bundle $L'$ and I know that I can represent it as $L\otimes (\omega_Y+\Delta)$, where $L$ is very ample. Do you know ANY vanishing theorems for line bundles on non-Gorenstein schemes? For example, my $\Delta$ is very explicit. What does one need to know about the singularities of $(Y,\Delta)$ in order to guarantee the vanishing?
Nov
17
asked Kawamata-Viehweg vanishing for non-Gorenstein singularities
Nov
17
accepted Group action on a stack and fixed points
Nov
17
comment Group action on a stack and fixed points
Great, thanks a lot!
Nov
16
asked Group action on a stack and fixed points
Sep
5
accepted cohen-macaulayness of reduced and non-reduced schemes
Sep
1
comment cohen-macaulayness of reduced and non-reduced schemes
Thanks a lot. Let me ask about a specific situation: assume that $Y$ is a Cohen-Macaulay scheme and $X$ is a divisor in it. Assume that we know the following: 1) Every component of $X$ is CM 2) Set-theoretically $X$ is the zero set of some regular function on $Y$. Can it be enough to conclude that $X$ is CM? If not, is there anything else one might require to gaurantee that $X$ is CM?
Aug
31
asked cohen-macaulayness of reduced and non-reduced schemes
Jul
5
awarded  Popular Question
Jun
25
awarded  Revival
Jun
13
comment Smooth map to the stack of G-bundles
For example, the fiber over the trivial $G$-bundles on some scheme $X$ is the space of maps from $X$ to $G/H$.
Jun
13
comment Smooth map to the stack of G-bundles
Angelo: what you wrote is wrong (it is only true for bundles over a point).