User Jim Humphreys

73 votes

9 answers

9k views

What are "classical groups"?

asked Dec 28, 2010 at 23:27

65 votes

6 answers

9k views

Origin of terms "flag", "flag manifold", "flag variety"?

asked Mar 13, 2011 at 15:02

52 votes

9 answers

26k views

Is Galois theory necessary (in a basic graduate algebra course)?

asked Aug 1, 2010 at 17:11

50 votes

5 answers

9k views

What role does the "dual Coxeter number" play in Lie theory (and should it be called the "Kac number")?

asked May 22, 2010 at 17:52

46 votes

2 answers

8k views

Definition of "finite group of Lie type"?

asked Jul 16, 2013 at 15:13

41 votes

2 answers

2k views

Implications of non-negativity of coefficients of arbitrary Kazhdan-Lusztig polynomials?

asked Nov 18, 2012 at 0:35

35 votes

3 answers

2k views

Is there any need to study Coxeter systems (W,S) with S infinite?

asked Jan 31, 2013 at 0:05

31 votes

4 answers

3k views

What was Casimir's precise role in describing the center of the universal enveloping algebra of a semisimple Lie algebra?

asked Oct 5, 2010 at 13:40

30 votes

0 answers

3k views

Greatly expanded new edition of a Bourbaki chapter on algebra?

asked Jan 13, 2016 at 14:51

30 votes

0 answers

999 views

Follow-up to Steinberg's problem (12) in his 1966 ICM talk?

asked Jul 18, 2016 at 20:24

26 votes

1 answer

2k views

Example of non-projective variety with non-semisimple Frobenius action on etale cohomology?

asked Aug 13, 2012 at 18:00

24 votes

2 answers

614 views

Uniform proof that a finite (irreducible real) reflection group is determined by its degrees?

asked Sep 29, 2013 at 22:40

23 votes

5 answers

4k views

Is there a reasonable way to refer to a 23 page article with 28 authors?

asked Sep 22, 2010 at 12:46

22 votes

4 answers

4k views

How did "Ore's Conjecture" become a conjecture?

asked Oct 6, 2011 at 20:27

20 votes

0 answers

764 views

Should the Dynkin diagrams of types $A_1$ and $B_2$ be labelled $C_1$ and $C_2$?

asked Jan 17, 2011 at 14:50

19 votes

2 answers

2k views

Dual versions of "folding" symmetric ADE Dynkin diagrams?

asked Nov 4, 2012 at 15:58

18 votes

4 answers

2k views

Origin of symbol l for a prime different from a fixed prime?

asked Jun 30, 2010 at 17:52

18 votes

0 answers

524 views

Applications of the surjectivity of Brauer's decomposition map over arbitrary fields?

asked Feb 29, 2012 at 23:55

18 votes

5 answers

2k views

Comparing algebraic group orbits over big and small algebraically closed fields

asked Dec 19, 2010 at 15:46

17 votes

2 answers

944 views

Are the unipotent and nilpotent varieties isomorphic in bad characteristics?

asked May 2, 2017 at 14:14

15 votes

0 answers

885 views

How much has been written down about Deligne's geometric approach to the order formula for a finite group of Lie type?

asked Aug 4, 2010 at 14:01

15 votes

4 answers

4k views

Simply connected algebraic groups and reductive subgroups of maximal rank

asked Apr 4, 2013 at 13:47

14 votes

1 answer

1k views

Uniform proof of dimension formula for minimal special nilpotent orbit?

asked Jun 7, 2011 at 15:15

13 votes

3 answers

1k views

Non-vanishing cohomology of line bundles on projective varieties in prime characteristic?

asked Nov 9, 2010 at 23:11

13 votes

0 answers

1k views

Can Wikipedia be a reliable (and sustainable) resource for advanced mathematics? [closed]

asked Mar 28, 2010 at 15:33

13 votes

4 answers

3k views

What is a "block" in an abelian category?

asked Apr 23, 2010 at 23:34

13 votes

0 answers

1k views

Source of a formula for tensor product multiplicities?

asked May 9, 2013 at 15:58

13 votes

1 answer

1k views

Convenient reference for subgroups of a finite semidirect product?

asked Jul 9, 2012 at 22:48

13 votes

0 answers

743 views

Earliest use of the term "linearly reductive"?

asked Jan 27, 2014 at 21:27

13 votes

0 answers

775 views

Is there a reasonable way to define "reductive Lie algebra" in prime characteristic?

asked Oct 29, 2017 at 15:07

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74 Questions

What are "classical groups"?

Origin of terms "flag", "flag manifold", "flag variety"?

Is Galois theory necessary (in a basic graduate algebra course)?

What role does the "dual Coxeter number" play in Lie theory (and should it be called the "Kac number")?

Definition of "finite group of Lie type"?

Implications of non-negativity of coefficients of arbitrary Kazhdan-Lusztig polynomials?

Is there any need to study Coxeter systems (W,S) with S infinite?

What was Casimir's precise role in describing the center of the universal enveloping algebra of a semisimple Lie algebra?

Greatly expanded new edition of a Bourbaki chapter on algebra?

Follow-up to Steinberg's problem (12) in his 1966 ICM talk?

Example of non-projective variety with non-semisimple Frobenius action on etale cohomology?

Uniform proof that a finite (irreducible real) reflection group is determined by its degrees?

Is there a reasonable way to refer to a 23 page article with 28 authors?

How did "Ore's Conjecture" become a conjecture?

Should the Dynkin diagrams of types $A_1$ and $B_2$ be labelled $C_1$ and $C_2$?

Dual versions of "folding" symmetric ADE Dynkin diagrams?

Origin of symbol l for a prime different from a fixed prime?

Applications of the surjectivity of Brauer's decomposition map over arbitrary fields?

Comparing algebraic group orbits over big and small algebraically closed fields

Are the unipotent and nilpotent varieties isomorphic in bad characteristics?

How much has been written down about Deligne's geometric approach to the order formula for a finite group of Lie type?

Simply connected algebraic groups and reductive subgroups of maximal rank

Uniform proof of dimension formula for minimal special nilpotent orbit?

Non-vanishing cohomology of line bundles on projective varieties in prime characteristic?

Can Wikipedia be a reliable (and sustainable) resource for advanced mathematics? [closed]

What is a "block" in an abelian category?

Source of a formula for tensor product multiplicities?

Convenient reference for subgroups of a finite semidirect product?

Earliest use of the term "linearly reductive"?

Is there a reasonable way to define "reductive Lie algebra" in prime characteristic?