User Allen Knutson

152 votes

Geometric interpretation of trace

answered Jan 31, 2010 at 2:09

91 votes

What should be learned in a first serious schemes course?

answered Jun 18, 2010 at 2:41

87 votes

Why aren't representations of monoids studied so much?

answered Sep 2, 2010 at 4:37

71 votes

What are your favorite instructional counterexamples?

answered Mar 5, 2010 at 19:51

35 votes

Accepted

Figure out the roots from the Dynkin diagram

answered Jan 28, 2010 at 16:32

34 votes

Accepted

Why "Classification" of 4 manifolds is NOT possible?

answered Aug 27, 2011 at 3:51

32 votes

Accepted

Why do Littlewood-Richardson coefficients describe the cohomology of the Grassmannian?

answered Feb 5, 2010 at 4:32

30 votes

What should be learned in a first serious schemes course?

answered Jun 17, 2010 at 18:52

24 votes

How much reading do you do before you attack a problem?

answered Jul 23, 2010 at 5:37

24 votes

Rep Theory Consequences of Bott--Weil--Borel

answered Feb 7, 2013 at 13:39

24 votes

Peter-Weyl vs. Schur-Weyl theorem

answered Apr 19, 2017 at 0:25

23 votes

Jokes in the sense of Littlewood: examples?

answered Nov 30, 2010 at 4:32

23 votes

Accepted

Finite subgroups of ${\rm SL}_2(\mathbb{Z})$ (reference request)

answered Jun 6, 2010 at 23:40

23 votes

What is the relationship between integrable systems and toric degenerations?

answered Jan 24, 2010 at 1:17

22 votes

Cohomology of Flag Varieties

answered Apr 17, 2010 at 15:46

22 votes

Examples of common false beliefs in mathematics

answered May 27, 2010 at 1:41

22 votes

Longest element of Weyl groups

answered Feb 10, 2011 at 2:21

21 votes

Algebraic geometry used "externally" (in problems without obvious algebraic structure).

answered Jun 23, 2010 at 22:16

20 votes

Accepted

deformation to the normal cone

answered Jun 2, 2010 at 14:32

20 votes

Unifying Geometry for Characteristic Classes

answered Dec 29, 2014 at 3:32

19 votes

What should be learned in a first serious schemes course?

answered Jun 18, 2010 at 22:50

19 votes

Suggestions for good notation

answered Oct 21, 2010 at 2:38

18 votes

What are your favorite puzzles/toys for introducing new mathematical concepts to students?

answered Aug 15, 2010 at 1:58

18 votes

Accepted

Oriention-Reversing Diffeomorphisms of a Manifold

answered Apr 19, 2010 at 1:06

18 votes

cohomology of BG, G compact Lie group

answered Apr 17, 2011 at 2:53

18 votes

Where do surreal numbers come from and what do they mean?

answered Apr 30, 2011 at 3:06

18 votes

Accepted

Proving Positivity for Schubert Calculus

answered Sep 11, 2018 at 1:53

18 votes

Why study Higher Sheaf Cohomology?

answered Oct 27, 2016 at 18:09

17 votes

Reference request: Grassmannian and Plucker coordinates in type B, C, D

answered Mar 30, 2019 at 14:52

17 votes

Accepted

Why do inner products require conjugation?

answered Jul 26, 2011 at 3:28

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276 Answers

Geometric interpretation of trace

What should be learned in a first serious schemes course?

Why aren't representations of monoids studied so much?

What are your favorite instructional counterexamples?

Figure out the roots from the Dynkin diagram

Why "Classification" of 4 manifolds is NOT possible?

Why do Littlewood-Richardson coefficients describe the cohomology of the Grassmannian?

What should be learned in a first serious schemes course?

How much reading do you do before you attack a problem?

Rep Theory Consequences of Bott--Weil--Borel

Peter-Weyl vs. Schur-Weyl theorem

Jokes in the sense of Littlewood: examples?

Finite subgroups of ${\rm SL}_2(\mathbb{Z})$ (reference request)

What is the relationship between integrable systems and toric degenerations?

Cohomology of Flag Varieties

Examples of common false beliefs in mathematics

Longest element of Weyl groups

Algebraic geometry used "externally" (in problems without obvious algebraic structure).

deformation to the normal cone

Unifying Geometry for Characteristic Classes

What should be learned in a first serious schemes course?

Suggestions for good notation

What are your favorite puzzles/toys for introducing new mathematical concepts to students?

Oriention-Reversing Diffeomorphisms of a Manifold

cohomology of BG, G compact Lie group

Where do surreal numbers come from and what do they mean?

Proving Positivity for Schubert Calculus

Why study Higher Sheaf Cohomology?

Reference request: Grassmannian and Plucker coordinates in type B, C, D

Why do inner products require conjugation?