bio | website | people.maths.ox.ac.uk/… |
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location | ||
age | ||
visits | member for | 5 years, 10 months |
seen | 8 hours ago | |
stats | profile views | 1,925 |
Aug
5 |
comment |
Is it possible to classify the indecomposable representations of the wild quiver with one vertex and two arrows using infinite sets of parameters?
You should also define what you mean by $\mathbb{F}_2$. I guess you mean the quiver with one vertex and two arrows? |
Jul
27 |
comment |
Is there a structure theorem or group law for finite groups generated by two elements?
mathoverflow.net/questions/59213/… |
Jul
15 |
comment |
Is there a topological Chevalley-Shephard-Todd Theorem?
So now we arrive at the converse, and Jason's argument. I agree there is something left to show... |
Jul
15 |
comment |
Is there a topological Chevalley-Shephard-Todd Theorem?
@Nico: so now I think I understand better: the quotient $\mathbb{C}^n \to \mathbb{C}^n/\Gamma$ is a quotient both in the category of topological spaces, and algebraic varieties. In particular, if $\Gamma$ is generated by pseudoreflections then it will be a topological manifold after all (by classical Chevalley-Shephard-Todd). |
Jul
15 |
comment |
Is there a topological Chevalley-Shephard-Todd Theorem?
@Nico: Sorry, I wrote that comment after a glass of wine. |
Jul
14 |
comment |
Is there a topological Chevalley-Shephard-Todd Theorem?
I don't know why there is a bounty ... it seems Jason has already answered the question! |
Apr
17 |
awarded | Enthusiast |
Apr
5 |
comment |
Cohomology of a local system and Deligne's weight filtration
@use54343: What do you mean by "your construction"? Restricting $IC$ to a strata? Doesn't taking $\mathcal{L}$ to the the local system I describe (an $IC$) recover what you want. (It is not clear to me how your second paragraph relates to the first. It seems your question is simply a question about variations of mixed Hodge structures on $\mathbb{C}^*$ and their cohomology. It would be much clearer if stated in this way.) |
Apr
4 |
comment |
Cohomology of a local system and Deligne's weight filtration
You are right to be suspicious. If one takes the direct image of the constant sheaf under $z \mapsto z^2$ one gets a local system which splits into two pieces, both of which are pure, and one of which has no cohomology. The non-trivial summand gives a counter-example to your hopes. Making $1 - f$ compatible with weight filtrations is a tricky business, in the mixed Hodge world it is given by the limit mixed Hodge structure... |
Apr
3 |
comment |
Status of Borho and Brylinski's irreducibility conjectures?
@Webstermeister To be honest I don't see immediately why it is the same question... |
Apr
2 |
comment |
Status of Borho and Brylinski's irreducibility conjectures?
This may or may not be relevant: front.math.ucdavis.edu/1405.3479 ! |
Feb
27 |
revised |
Residual finiteness: why do we care?
added 1 character in body |
Dec
12 |
answered | Example to show that the inverse image under a finite morphism is not t-exact with respect to the perverse t-structure |
Dec
9 |
answered | Representation of GL(n, F_p) over F_p, for n small |
Dec
9 |
answered | counting points on nilpotent Springer fiber |
Dec
9 |
comment |
counting points on nilpotent Springer fiber
One should be a little careful here. De Concini, Lusztig and Procesi do not show the existence of an affine paving in exceptional type. Moreover I think that the argument with a torus having finitely many fixed points only works in type $A$. |
Dec
3 |
awarded | Necromancer |
Dec
2 |
revised |
Motivation behind the construction of Deligne and Lusztig
edited body |
Dec
2 |
answered | Motivation behind the construction of Deligne and Lusztig |
Nov
24 |
comment |
Stability conditions of coherent sheaves on abelian 3-folds
there has recently been big progress here. See Maciocia, Piyaratne "Fourier-Mukai transforms and Bridgeland stability conditions on abelian threefolds" I and II and "The space of stability conditions for abelian threefolds, and some Calabi-Yau threefolds" by Beyer, Macri and Stellari. (I am not an expert and so could have missed an important reference, but you certainly should be aware of these papers.) |