User Makhalan Duff

10 votes

4 answers

926 views

Intuition behind existence of moduli space of stable curves

asked Apr 12, 2010 at 16:39

9 votes

3 answers

2k views

Confusion about how the first cohomology classifies torsors

asked Apr 28, 2010 at 23:11

9 votes

4 answers

3k views

Is there a (satisfying) proof that cellular cohomology is isomorphic to simplicial cohomology that doesn't use relative cohomlogy?

asked May 13, 2015 at 22:05

8 votes

4 answers

2k views

Cohomological dimension

asked May 30, 2010 at 18:13

8 votes

2 answers

2k views

Functoriality of fundamental group via deck transformations

asked May 11, 2010 at 13:46

8 votes

1 answer

625 views

How do branched coverings of complex surfaces "fit" with branched coverings of curves?

asked Jul 31, 2010 at 15:26

8 votes

1 answer

975 views

Zariski-style valuation theory

asked Sep 2, 2010 at 17:36

8 votes

2 answers

490 views

If the n-th root of unity exists locally, does it exist globally?

asked Dec 22, 2010 at 3:35

8 votes

0 answers

1k views

What's a good reference about gerbes and bands?

asked Jan 30, 2011 at 22:42

8 votes

3 answers

900 views

Centralizers of elements in free profinite groups

asked Apr 23, 2011 at 0:39

8 votes

3 answers

2k views

Why is the zeta function of a variety over a finite field not a polynomial? (question about motives)

asked Mar 15, 2011 at 21:58

8 votes

1 answer

1k views

For which fields is the inverse Galois problem known?

asked Mar 3, 2012 at 2:13

7 votes

2 answers

1k views

A split short exact sequence of algebraic fundamental groups

asked May 3, 2010 at 20:59

6 votes

1 answer

766 views

Group cohomology and cohomology in non-abelian categories

asked Oct 30, 2010 at 14:20

6 votes

1 answer

1k views

What is the intuition behind the proof of the algebraic version of Cartan's theorem A?

asked Nov 13, 2011 at 18:46

6 votes

2 answers

528 views

Expressing Galois actions on fundamental groups explicitly

asked Jul 24, 2011 at 19:31

6 votes

0 answers

691 views

Are all henselian fields algebraic over complete fields?

asked May 4, 2012 at 0:08

5 votes

1 answer

436 views

Is the set of all curves that have a Galois map to the projective line Zariski closed in M_g?

asked Sep 5, 2011 at 17:26

5 votes

2 answers

821 views

Is there for every variety X an abelian variety A such that their 1st l-adic cohomologies are isomorphic?

asked Sep 8, 2011 at 1:03

5 votes

0 answers

374 views

Does Grothendieck-Teichmuller tell us something about Galois actions, or just about Gal(Q)?

asked Nov 12, 2011 at 23:22

5 votes

1 answer

631 views

How does Schlessinger's criterion sit with Grothendieck Existence (aka GFGA)?

asked Jan 27, 2011 at 15:13

5 votes

1 answer

446 views

Given a branched cover with branch cycle description $(g_1,...,g_r)$, does $g_i$ generate some decomposition group?

asked May 5, 2011 at 1:27

5 votes

1 answer

998 views

When is a sheaf on a scheme extendable to a representable functor?

asked Jun 17, 2011 at 23:17

5 votes

0 answers

406 views

Existence of weird automorphisms in finite groups

asked Mar 25, 2011 at 22:44

5 votes

1 answer

196 views

Understanding different Q-models of a curve over C

asked Apr 29, 2010 at 16:14

5 votes

3 answers

921 views

A condition on finite groups

asked May 30, 2010 at 20:26

5 votes

2 answers

1k views

Ramification in morphisms of surfaces

asked Aug 31, 2010 at 19:18

4 votes

1 answer

286 views

Can a branched cover of relative curves be suddenly ramified along a vertical divisor if you blow up the curve on the bottom?

asked Jul 12, 2010 at 21:11

4 votes

1 answer

286 views

Predicting the behavior of the normalization without normalizing

asked Oct 5, 2010 at 0:02

4 votes

1 answer

408 views

Are all solvable groups regularly realizable over Q(x)?

asked Nov 19, 2010 at 22:32

Stack Exchange Network

84 Questions

Intuition behind existence of moduli space of stable curves

Confusion about how the first cohomology classifies torsors

Is there a (satisfying) proof that cellular cohomology is isomorphic to simplicial cohomology that doesn't use relative cohomlogy?

Cohomological dimension

Functoriality of fundamental group via deck transformations

How do branched coverings of complex surfaces "fit" with branched coverings of curves?

Zariski-style valuation theory

If the n-th root of unity exists locally, does it exist globally?

What's a good reference about gerbes and bands?

Centralizers of elements in free profinite groups

Why is the zeta function of a variety over a finite field not a polynomial? (question about motives)

For which fields is the inverse Galois problem known?

A split short exact sequence of algebraic fundamental groups

Group cohomology and cohomology in non-abelian categories

What is the intuition behind the proof of the algebraic version of Cartan's theorem A?

Expressing Galois actions on fundamental groups explicitly

Are all henselian fields algebraic over complete fields?

Is the set of all curves that have a Galois map to the projective line Zariski closed in M_g?

Is there for every variety X an abelian variety A such that their 1st l-adic cohomologies are isomorphic?

Does Grothendieck-Teichmuller tell us something about Galois actions, or just about Gal(Q)?

How does Schlessinger's criterion sit with Grothendieck Existence (aka GFGA)?

Given a branched cover with branch cycle description $(g_1,...,g_r)$, does $g_i$ generate some decomposition group?

When is a sheaf on a scheme extendable to a representable functor?

Existence of weird automorphisms in finite groups

Understanding different Q-models of a curve over C

A condition on finite groups

Ramification in morphisms of surfaces

Can a branched cover of relative curves be suddenly ramified along a vertical divisor if you blow up the curve on the bottom?

Predicting the behavior of the normalization without normalizing

Are all solvable groups regularly realizable over Q(x)?