User Mikhail Borovoi

27 votes

1 answer

1k views

Nonabelian topological fundamental group of a conjugate variety

asked Apr 3, 2015 at 13:32

24 votes

3 answers

2k views

Spin group as an automorphism group

asked Jul 29, 2013 at 13:21

19 votes

3 answers

2k views

Second nonabelian group cohomology: cocycles vs. gerbes

asked May 10, 2013 at 12:26

17 votes

2 answers

1k views

Is the wonderful compactification of a spherical homogeneous variety always projective?

asked Jun 21, 2016 at 18:54

16 votes

3 answers

2k views

Diagonalizable subgroups of a connected linear algebraic group

asked Apr 6, 2011 at 8:00

15 votes

2 answers

845 views

Elements of arbitrary large order in the first Galois cohomology of an elliptic curve

asked May 21, 2016 at 15:29

14 votes

3 answers

1k views

Infiniteness of the Galois cohomology over a number field with coefficients in a finite Galois module

asked May 22, 2016 at 5:06

13 votes

1 answer

990 views

Is -1 a sum of 2 squares in a certain field K?

asked May 5, 2010 at 18:23

12 votes

2 answers

707 views

Defining abstract varieties and their morphisms over a finitely generated subfield of the base field

asked Oct 5, 2018 at 14:47

11 votes

2 answers

589 views

To describe an invariant trivector in dimension 8 geometrically

asked Nov 24, 2020 at 17:24

11 votes

1 answer

328 views

Galois cohomology class of a reductive group not coming from a torus

asked Jun 7, 2022 at 6:41

11 votes

2 answers

2k views

Mostow's theorem on algebraic groups

asked Sep 15, 2012 at 12:09

11 votes

2 answers

653 views

Abelian variety with prescribed endomorphism ring

asked Aug 11, 2016 at 15:05

10 votes

1 answer

577 views

Does every Shimura variety contain a generic point defined over a number field?

asked Aug 12, 2016 at 18:09

10 votes

1 answer

549 views

A Galois extension over $\mathbb{Q}$ with Galois group $A_4$ and with cyclic decomposition groups

asked Jun 15, 2016 at 21:19

10 votes

4 answers

2k views

Connected components of the orthogonal group O(2n) in characteristic 2.

asked Mar 25, 2010 at 14:23

9 votes

4 answers

633 views

Algebraic cycles of dimension 2 on the square of a generic abelian surface

asked Apr 6, 2010 at 16:34

9 votes

2 answers

464 views

Automorphisms of $SL_n$ as a variety

asked Jan 15, 2013 at 16:12

9 votes

1 answer

1k views

Nonabelian $H^2$ and Galois descent

asked Jun 29, 2016 at 15:23

9 votes

0 answers

243 views

Rationality of a certain real algebraic variety

asked May 2, 2016 at 10:41

9 votes

1 answer

665 views

Group schemes, adeles, double cosets, and étale cohomology

asked May 14, 2015 at 6:04

9 votes

1 answer

825 views

Forms of ${\rm SL}(2)$

asked Dec 5, 2020 at 13:02

9 votes

1 answer

371 views

For which subgroups the transfer map kills a given element of a group?

asked Oct 8, 2023 at 6:30

8 votes

2 answers

482 views

Parabolics and simple roots for a special unitary group: reference request

asked Mar 8, 2021 at 13:05

8 votes

1 answer

308 views

Algebraic points of uniformly bounded degree on an algebraic variety

asked May 20, 2016 at 17:30

7 votes

1 answer

240 views

Hasse principle for $H^2$ of a maximal torus of a split simply connected group?

asked Aug 2, 2016 at 17:42

7 votes

0 answers

329 views

A basic question on a base change of a homogeneous space of a linear algebraic group

asked Jun 24, 2017 at 14:18

7 votes

2 answers

231 views

Non-semisimple symmetric subgroups of simply connected simple algebraic groups

asked Mar 27, 2017 at 15:32

7 votes

2 answers

2k views

Reductive subgroup corresponding to a subdiagram of the Dynkin diagram of a simple group

asked Mar 19, 2010 at 15:52

7 votes

2 answers

736 views

What does a homogeneous space of a linear algebraic group know about the group?

asked Feb 23, 2011 at 19:42

Stack Exchange Network

142 Questions

Nonabelian topological fundamental group of a conjugate variety

Spin group as an automorphism group

Second nonabelian group cohomology: cocycles vs. gerbes

Is the wonderful compactification of a spherical homogeneous variety always projective?

Diagonalizable subgroups of a connected linear algebraic group

Elements of arbitrary large order in the first Galois cohomology of an elliptic curve

Infiniteness of the Galois cohomology over a number field with coefficients in a finite Galois module

Is -1 a sum of 2 squares in a certain field K?

Defining abstract varieties and their morphisms over a finitely generated subfield of the base field

To describe an invariant trivector in dimension 8 geometrically

Galois cohomology class of a reductive group not coming from a torus

Mostow's theorem on algebraic groups

Abelian variety with prescribed endomorphism ring

Does every Shimura variety contain a generic point defined over a number field?

A Galois extension over $\mathbb{Q}$ with Galois group $A_4$ and with cyclic decomposition groups

Connected components of the orthogonal group O(2n) in characteristic 2.

Algebraic cycles of dimension 2 on the square of a generic abelian surface

Automorphisms of $SL_n$ as a variety

Nonabelian $H^2$ and Galois descent

Rationality of a certain real algebraic variety

Group schemes, adeles, double cosets, and étale cohomology

Forms of ${\rm SL}(2)$

For which subgroups the transfer map kills a given element of a group?

Parabolics and simple roots for a special unitary group: reference request

Algebraic points of uniformly bounded degree on an algebraic variety

Hasse principle for $H^2$ of a maximal torus of a split simply connected group?

A basic question on a base change of a homogeneous space of a linear algebraic group

Non-semisimple symmetric subgroups of simply connected simple algebraic groups

Reductive subgroup corresponding to a subdiagram of the Dynkin diagram of a simple group

What does a homogeneous space of a linear algebraic group know about the group?