User Allen Knutson

154 votes

7 answers

83k views

Where to buy premium white chalk in the U.S., like they have at RIMS? [closed]

asked May 28, 2010 at 14:08

79 votes

26 answers

6k views

What would you want on a Lie theory cheat poster?

asked Apr 26, 2011 at 13:57

42 votes

3 answers

2k views

Are there "real" vs. "quaternionic" conjugacy classes in finite groups?

asked Nov 22, 2010 at 3:31

33 votes

2 answers

2k views

If a field extension gives affine space, was it already affine space?

asked Jan 27, 2011 at 19:27

22 votes

1 answer

2k views

Modern reference for maximal connected subgroups of compact Lie groups

asked Apr 1, 2011 at 19:42

22 votes

0 answers

958 views

Poincaré-Hopf and Mathai-Quillen for Chern classes?

asked Mar 29, 2010 at 15:02

22 votes

3 answers

1k views

What classification theorems have been improved by re-categorizing?

asked Nov 20, 2012 at 13:46

21 votes

1 answer

2k views

When does the relative differential $df=0$ imply that $f$ comes from the base?

asked Sep 13, 2011 at 16:29

20 votes

4 answers

2k views

Topological spaces made by identifying opposite faces of a cube?

asked Mar 5, 2012 at 18:20

20 votes

2 answers

1k views

Why do flag manifolds, in the P(V_rho) embedding, look like products of P^1s?

asked Feb 9, 2010 at 14:57

20 votes

0 answers

553 views

Hall's Marriage Theorem and intervals

asked Apr 11, 2013 at 3:46

18 votes

2 answers

1k views

Grothendieck ring of "varieties carrying a function"

asked Sep 25, 2012 at 20:45

18 votes

3 answers

1k views

Where to break paragraphs in a proof?

asked Sep 14, 2013 at 19:16

18 votes

0 answers

377 views

Deforming a basis of a polynomial ring

asked Mar 10, 2015 at 1:40

17 votes

2 answers

949 views

Is the singular locus ideal preserved by all derivations?

asked Jul 24, 2011 at 19:12

16 votes

1 answer

644 views

Subquotients in the Verma filtration on Verma modules

asked Nov 14, 2014 at 4:10

15 votes

4 answers

1k views

Number of $\mathbb F_p$ points constant mod $p$?

asked Jun 25, 2015 at 19:44

15 votes

2 answers

497 views

Coxeter exchanges in non-reduced words

asked Nov 9, 2015 at 20:11

15 votes

1 answer

673 views

Smooth bases of matroids

asked Jun 19, 2012 at 15:29

15 votes

2 answers

647 views

Relating two characterizations of ${\mathfrak sl}_{n > 2}$ among simple Lie algebras

asked May 6, 2013 at 15:53

14 votes

1 answer

959 views

Founding of homological without quite involving derived categories

asked Jan 7, 2010 at 1:49

13 votes

0 answers

557 views

Are the extra vertices in Nakajima's doubling of a quiver related to Langlands duality?

asked Nov 29, 2010 at 15:58

13 votes

1 answer

679 views

Obstructions to formally integrating vector fields in characteristic p?

asked Jul 30, 2011 at 16:53

13 votes

2 answers

807 views

Image of a map on cohomology rings

asked Sep 24, 2019 at 23:42

13 votes

2 answers

601 views

Computing intersection of subrings

asked Feb 6, 2015 at 14:09

12 votes

1 answer

2k views

Replacement for derivations in characteristic p?

asked Jul 27, 2011 at 18:12

12 votes

0 answers

326 views

Analytic contraction of the Stone-Cech compactification of $\mathbb C$

asked Jan 7, 2014 at 17:17

11 votes

2 answers

580 views

Temperley-Lieb algebras for other Weyl groups?

asked May 28, 2013 at 17:54

11 votes

1 answer

1k views

Is there a "good" reason that the universal central extension of $SL(2,\mathbb Z)$ is $Br_3$?

asked Dec 22, 2014 at 4:08

11 votes

4 answers

629 views

Heisenberg algebra from Pieri operators and their transposes?

asked May 17, 2011 at 21:25

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81 Questions

Where to buy premium white chalk in the U.S., like they have at RIMS? [closed]

What would you want on a Lie theory cheat poster?

Are there "real" vs. "quaternionic" conjugacy classes in finite groups?

If a field extension gives affine space, was it already affine space?

Modern reference for maximal connected subgroups of compact Lie groups

Poincaré-Hopf and Mathai-Quillen for Chern classes?

What classification theorems have been improved by re-categorizing?

When does the relative differential $df=0$ imply that $f$ comes from the base?

Topological spaces made by identifying opposite faces of a cube?

Why do flag manifolds, in the P(V_rho) embedding, look like products of P^1s?

Hall's Marriage Theorem and intervals

Grothendieck ring of "varieties carrying a function"

Where to break paragraphs in a proof?

Deforming a basis of a polynomial ring

Is the singular locus ideal preserved by all derivations?

Subquotients in the Verma filtration on Verma modules

Number of $\mathbb F_p$ points constant mod $p$?

Coxeter exchanges in non-reduced words

Smooth bases of matroids

Relating two characterizations of ${\mathfrak sl}_{n > 2}$ among simple Lie algebras

Founding of homological without quite involving derived categories

Are the extra vertices in Nakajima's doubling of a quiver related to Langlands duality?

Obstructions to formally integrating vector fields in characteristic p?

Image of a map on cohomology rings

Computing intersection of subrings

Replacement for derivations in characteristic p?

Analytic contraction of the Stone-Cech compactification of $\mathbb C$

Temperley-Lieb algebras for other Weyl groups?

Is there a "good" reason that the universal central extension of $SL(2,\mathbb Z)$ is $Br_3$?

Heisenberg algebra from Pieri operators and their transposes?