Mikhail Borovoi's user avatar
Mikhail Borovoi's user avatar
Mikhail Borovoi's user avatar
Mikhail Borovoi
  • Member for 14 years, 1 month
  • Last seen this week
9 votes
2 answers
2k views

Mostow's theorem on algebraic groups

10 votes
4 answers
2k views

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

24 votes
3 answers
2k views

Spin group as an automorphism group

19 votes
3 answers
2k views

Second nonabelian group cohomology: cocycles vs. gerbes

7 votes
2 answers
1k views

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

15 votes
3 answers
1k views

Diagonalizable subgroups of a connected linear algebraic group

17 votes
2 answers
1k views

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

27 votes
1 answer
1k views

Nonabelian topological fundamental group of a conjugate variety

3 votes
2 answers
1k views

Groupoids vs. action groupoids

5 votes
3 answers
1k views

Splitting of a division algebra with an involution of second kind

9 votes
1 answer
1k views

Nonabelian $H^2$ and Galois descent

13 votes
3 answers
1k views

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

13 votes
1 answer
980 views

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

5 votes
5 answers
961 views

Connected groupoids and action groupoids

7 votes
2 answers
850 views

Is this exact sequence known?

15 votes
2 answers
829 views

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

3 votes
1 answer
811 views

Equivalence and weak equivalence of groupoids

6 votes
3 answers
740 views

Quotient of a reductive group by a non-smooth central finite subgroup

9 votes
1 answer
698 views

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

7 votes
2 answers
682 views

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

12 votes
2 answers
678 views

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

4 votes
2 answers
665 views

Reference request: the comparison theorem for the étale fundamental group

7 votes
2 answers
655 views

Élie Cartan's paper "Les groupes réels simples, finis et continus" of 1914

7 votes
3 answers
643 views

Infinite Galois descent for finitely generated commutative algebras over a field

9 votes
4 answers
631 views

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

11 votes
2 answers
629 views

Abelian variety with prescribed endomorphism ring

9 votes
1 answer
629 views

Group schemes, adeles, double cosets, and étale cohomology

6 votes
1 answer
613 views

Anti-holomorphic involutions of a complex linear algebraic group

5 votes
1 answer
604 views

Non-vanishing of the Tate-Shafarevich kernel in group cohomology

4 votes
0 answers
599 views

Closed subgroups of a connected Lie group

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