User Paul Siegel

18 votes

2 answers

3k views

A question about the proof of Mostow rigidity

asked Apr 20, 2010 at 16:40

18 votes

3 answers

1k views

Periodicity theorems in (generalized) cohomology theories

asked Jul 17, 2010 at 17:15

16 votes

2 answers

1k views

Is there an effective way to calculate K-theory using Morse functions?

asked Apr 3, 2013 at 14:37

15 votes

2 answers

780 views

What geometric information is carried by the Fourier coefficients of the components of a closed curve?

asked Mar 27, 2014 at 16:26

14 votes

4 answers

1k views

What is the right definition of "real von Neumann algebra"?

asked Feb 9, 2011 at 16:20

14 votes

3 answers

3k views

Reference Request: Relative De Rham Cohomology

asked May 4, 2012 at 19:02

14 votes

2 answers

387 views

What are some useful invariants for distinguishing between random graph models?

asked Aug 31, 2015 at 20:43

14 votes

2 answers

3k views

When is sin(r \pi) expressible in radicals for r rational?

asked Aug 21, 2010 at 13:03

13 votes

1 answer

4k views

Modulus of Continuity

asked Nov 21, 2011 at 15:24

12 votes

2 answers

2k views

What is the Poincare dual of a symplectic form?

asked Oct 15, 2010 at 21:35

11 votes

1 answer

2k views

Stacks vs. Groupoids

asked Apr 20, 2010 at 16:13

11 votes

4 answers

1k views

Relative K-theory and split exact sequences of C* algebras

asked May 15, 2010 at 2:02

10 votes

1 answer

898 views

Category Theory / Topology Question

asked Jun 7, 2010 at 19:44

10 votes

3 answers

656 views

Must a surface obtained by exponentiating a plane in a tangent space of a Riemannian manifold be geodesically convex?

asked Mar 13, 2010 at 21:55

10 votes

4 answers

4k views

It is well-known that hyperbolic space is delta-hyperbolic, but what is delta?

asked Apr 30, 2010 at 2:18

10 votes

3 answers

922 views

Cohomology ring of BG

asked Dec 20, 2012 at 19:10

10 votes

4 answers

723 views

Does the centroid depend continuously on the curve?

asked Mar 4, 2014 at 20:52

8 votes

2 answers

2k views

Small eigenvalues and spectral clustering

asked Jul 11, 2013 at 19:31

7 votes

5 answers

2k views

Is there a purely algebraic criterion which characterizes the real algebraic numbers?

asked May 24, 2010 at 0:27

7 votes

2 answers

773 views

Can anyone calculate KK(A,B) when neither A or B are the complex numbers?

asked Jan 5, 2011 at 14:54

7 votes

2 answers

526 views

Integrality of the canonical trace and topology

asked Mar 14, 2011 at 19:58

7 votes

1 answer

391 views

What are the relations in the unbounded model of K-homology?

asked Jan 26, 2012 at 20:22

5 votes

1 answer

2k views

Maurer-Cartan 1-form as a connection 1-form

asked Jan 25, 2011 at 17:07

5 votes

2 answers

529 views

How do you prove that every curve of constant width is convex?

asked Mar 8, 2013 at 22:44

5 votes

1 answer

420 views

Which positive definite symmetric matrices have solvable characteristic polynomial?

asked Nov 18, 2013 at 13:15

5 votes

1 answer

275 views

Is there a good notion of "random bounded linear map" on a separable Hilbert space?

asked May 14, 2014 at 11:17

5 votes

1 answer

104 views

Is a connected graph uniquely determined by its weighted 2-step graph?

asked Jul 26, 2014 at 7:40

4 votes

1 answer

873 views

Can the Darboux theorem be strengthened?

asked Oct 15, 2010 at 21:20

4 votes

0 answers

268 views

Can one pose a Toeplitz index problem associated to a discrete group?

asked Jul 16, 2010 at 18:15

4 votes

0 answers

166 views

Minimal Diffeomorphisms and Cohomology

asked May 6, 2010 at 22:30

Stack Exchange Network

66 Questions

A question about the proof of Mostow rigidity

Periodicity theorems in (generalized) cohomology theories

Is there an effective way to calculate K-theory using Morse functions?

What geometric information is carried by the Fourier coefficients of the components of a closed curve?

What is the right definition of "real von Neumann algebra"?

Reference Request: Relative De Rham Cohomology

What are some useful invariants for distinguishing between random graph models?

When is sin(r \pi) expressible in radicals for r rational?

Modulus of Continuity

What is the Poincare dual of a symplectic form?

Stacks vs. Groupoids

Relative K-theory and split exact sequences of C* algebras

Category Theory / Topology Question

Must a surface obtained by exponentiating a plane in a tangent space of a Riemannian manifold be geodesically convex?

It is well-known that hyperbolic space is delta-hyperbolic, but what is delta?

Cohomology ring of BG

Does the centroid depend continuously on the curve?

Small eigenvalues and spectral clustering

Is there a purely algebraic criterion which characterizes the real algebraic numbers?

Can anyone calculate KK(A,B) when neither A or B are the complex numbers?

Integrality of the canonical trace and topology

What are the relations in the unbounded model of K-homology?

Maurer-Cartan 1-form as a connection 1-form

How do you prove that every curve of constant width is convex?

Which positive definite symmetric matrices have solvable characteristic polynomial?

Is there a good notion of "random bounded linear map" on a separable Hilbert space?

Is a connected graph uniquely determined by its weighted 2-step graph?

Can the Darboux theorem be strengthened?

Can one pose a Toeplitz index problem associated to a discrete group?

Minimal Diffeomorphisms and Cohomology