User David Treumann

60 votes

Homotopy groups of Lie groups

answered Dec 15, 2009 at 18:00

26 votes

Accepted

Topologically contractible algebraic varieties

answered Dec 2, 2009 at 19:55

10 votes

Which R-algebras are the group ring of some group over a ring R?

answered Jan 31, 2010 at 18:07

8 votes

Accepted

What are the implications of torsion in H^2 for geometric quantization?

answered Apr 28, 2010 at 1:04

8 votes

Topology on the space of constructible sheaves

answered Mar 19, 2016 at 16:05

7 votes

Accepted

Calculating Mayer-Vietoris efficiently

answered Feb 9, 2015 at 18:57

7 votes

Which commutative groups are the group of units of some field?

answered Jan 26, 2010 at 15:48

7 votes

When are there enough projective sheaves on a space X?

answered Nov 13, 2009 at 17:04

6 votes

Accepted

D-modules supported on the nilpotent cone

answered Oct 28, 2009 at 3:59

5 votes

Accepted

Over which schemes can there exist non-trivial G_a bundles?

answered Oct 28, 2009 at 4:25

5 votes

Logic comment in Mumford's Red Book

answered Nov 12, 2009 at 17:01

3 votes

Equivariant Derived Categories via their properties.

answered Oct 30, 2009 at 6:29

3 votes

Accepted

Hypercube decomposition of perverse sheaves

answered Nov 28, 2009 at 17:49

3 votes

How should I think about correspondences?

answered Nov 29, 2009 at 18:27

3 votes

Understanding the unreducedness of a subscheme supported on fixed points

answered Oct 24, 2010 at 4:50

2 votes

When is the derived category of representations of a finite poset equivalent to its opposite?

answered Sep 26, 2012 at 23:50

2 votes

Is there a theory of differential equations for smooth correspondences?

answered Dec 2, 2009 at 17:51

2 votes

Making D-modules on affine varieties more explicit

answered Nov 1, 2009 at 22:02

2 votes

What are the higher homotopy groups of Spec Z ?

answered Nov 3, 2009 at 17:49

1 vote

Thom first isotopy lemma in o-minimal structures

answered May 2, 2010 at 17:07

1 vote

(∞, 1)-categorical description of equivariant homotopy theory

answered Oct 28, 2009 at 22:58

0 votes

Do convolution and multiplication satisfy any nontrivial algebraic identities?

answered Oct 31, 2009 at 4:42

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22 Answers

Homotopy groups of Lie groups

Topologically contractible algebraic varieties

Which R-algebras are the group ring of some group over a ring R?

What are the implications of torsion in H^2 for geometric quantization?

Topology on the space of constructible sheaves

Calculating Mayer-Vietoris efficiently

Which commutative groups are the group of units of some field?

When are there enough projective sheaves on a space X?

D-modules supported on the nilpotent cone

Over which schemes can there exist non-trivial G_a bundles?

Logic comment in Mumford's Red Book

Equivariant Derived Categories via their properties.

Hypercube decomposition of perverse sheaves

How should I think about correspondences?

Understanding the unreducedness of a subscheme supported on fixed points

When is the derived category of representations of a finite poset equivalent to its opposite?

Is there a theory of differential equations for smooth correspondences?

Making D-modules on affine varieties more explicit

What are the higher homotopy groups of Spec Z ?

Thom first isotopy lemma in o-minimal structures

(∞, 1)-categorical description of equivariant homotopy theory

Do convolution and multiplication satisfy any nontrivial algebraic identities?