All Questions
4 questions
5
votes
0
answers
197
views
Torsion-free sheaf cohomology over discrete valuation rings
Let $R$ be a Henselian discrete valuation rings with algebraically closed residue field and $X$ be a regular, flat, proper $R$-scheme. Assume that the generic fiber to the natural morphism from $X$ to ...
11
votes
2
answers
780
views
Deformations of a blowup
Let $S$ be a smooth projective surface over $\mathbb{C}$. (I guess this can be more general—higher dimension, other ground fields, non-projective, maybe even singular?—and I'dd like to hear that.) Let ...
3
votes
0
answers
175
views
Cycle class map in non-smooth family of projective varieties
Let $\pi:\mathcal{X} \to T$ be a family of smooth projective complex varieties. Assume $T$ is quasi-projective, reduced, irreducible but not smooth and of positive dimension. Let $\mathcal{Z}$ be a ...
9
votes
1
answer
443
views
Reverse Engineering to find deformation problem (from cohomology groups)?
One of my favorite explanation of the cohomology groups of low degree is that they arise as the automorphism group, tangent space and obstruction space (or where the obstruction lives) of a certain ...