User Qiaochu Yuan

18 votes

12 answers

5k views

What are some fundamental "sources" for the appearance of pi in mathematics?

asked Mar 14, 2010 at 17:00

18 votes

2 answers

4k views

What is the physical meaning of a Lie algebra symmetry?

asked May 17, 2010 at 5:19

18 votes

2 answers

3k views

Is Soergel's proof of Kazhdan-Lusztig positivity for Weyl groups independent of other proofs?

asked Jun 24, 2010 at 17:40

18 votes

2 answers

1k views

The Riemann zeta function and Haar measure on the profinite integers

asked Aug 1, 2010 at 21:59

17 votes

3 answers

2k views

What is a reasonable finitary analogue of the statement that harmonic functions are smooth?

asked Jul 28, 2010 at 2:43

17 votes

1 answer

1k views

Is there an "arithmetic cobordism category"?

asked May 26, 2010 at 8:26

17 votes

1 answer

734 views

Reference request: a conjecture of Rota on positive functions of a random variable

asked Sep 19, 2012 at 2:21

17 votes

2 answers

848 views

What is the conceptual significance of supercommutativity?

asked Nov 6, 2009 at 20:07

17 votes

2 answers

2k views

Why does the Gamma function satisfy a functional equation?

asked Feb 5, 2010 at 6:33

16 votes

2 answers

1k views

Which commutative groups are the group of units of some field?

asked Jan 26, 2010 at 6:18

16 votes

4 answers

1k views

Iterated adjoint functors

asked Dec 27, 2009 at 4:06

16 votes

2 answers

1k views

Which topological spaces have the property that their sheaves of continuous functions are determined by their global sections?

asked Nov 20, 2009 at 6:24

16 votes

1 answer

976 views

Which categories are the categories of models of a Lawvere theory?

asked Jun 10, 2013 at 21:46

16 votes

2 answers

1k views

Is every symplectic manifold a Hamiltonian reduction of a cotangent bundle?

asked Dec 5, 2013 at 22:02

15 votes

3 answers

1k views

What's the origin of the naming convention for the standard basis of $\mathfrak{sl}_2(\mathbb{C}) $?

asked Mar 11, 2010 at 4:17

15 votes

2 answers

2k views

Propositional logic with categories

asked Oct 23, 2010 at 10:19

15 votes

3 answers

1k views

Does there exist a meromorphic function all of whose Taylor coefficients are prime?

asked Nov 19, 2009 at 21:50

15 votes

3 answers

855 views

Are supervector spaces the representations of a Hopf algebra?

asked Nov 8, 2009 at 15:26

15 votes

7 answers

4k views

Different definitions of the dimension of an algebra

asked Oct 25, 2009 at 22:02

15 votes

1 answer

715 views

What are the Schur functions of the eigenvalues of a non-negative integer matrix counting?

asked Oct 13, 2009 at 21:23

14 votes

3 answers

2k views

Poisson algebras as deformations vs. Poisson algebras in algebraic topology

asked Sep 2, 2011 at 23:14

14 votes

2 answers

4k views

Direct construction of the Stone-Čech compactification using ultrafilters?

asked Dec 16, 2010 at 9:09

14 votes

4 answers

2k views

Where does Segal's category come from?

asked Oct 9, 2013 at 0:47

14 votes

0 answers

605 views

Is the Zariski density proof of Cayley-Hamilton circular?

asked Jul 27 at 22:41

13 votes

2 answers

1k views

Obstructions to the existence of stable (and unstable?) complex structures?

asked Jun 15, 2014 at 20:34

13 votes

1 answer

919 views

Is there a "deep" reason that the first Perrin pseudoprime is large?

asked Dec 20, 2010 at 7:23

13 votes

3 answers

1k views

Frobenius elements from the point of view of étale fundamental groups

asked Feb 1, 2011 at 15:11

13 votes

4 answers

1k views

Reference request: probability / ergodic theory without measure spaces

asked Jan 22, 2011 at 21:42

13 votes

2 answers

783 views

Iterating monoid categories

asked Sep 4, 2012 at 3:18

13 votes

2 answers

1k views

Combinatorial proof of (a special case of) the spectral theorem?

asked May 7, 2010 at 3:09

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179 Questions

What are some fundamental "sources" for the appearance of pi in mathematics?

What is the physical meaning of a Lie algebra symmetry?

Is Soergel's proof of Kazhdan-Lusztig positivity for Weyl groups independent of other proofs?

The Riemann zeta function and Haar measure on the profinite integers

What is a reasonable finitary analogue of the statement that harmonic functions are smooth?

Is there an "arithmetic cobordism category"?

Reference request: a conjecture of Rota on positive functions of a random variable

What is the conceptual significance of supercommutativity?

Why does the Gamma function satisfy a functional equation?

Which commutative groups are the group of units of some field?

Iterated adjoint functors

Which topological spaces have the property that their sheaves of continuous functions are determined by their global sections?

Which categories are the categories of models of a Lawvere theory?

Is every symplectic manifold a Hamiltonian reduction of a cotangent bundle?

What's the origin of the naming convention for the standard basis of $\mathfrak{sl}_2(\mathbb{C}) $?

Propositional logic with categories

Does there exist a meromorphic function all of whose Taylor coefficients are prime?

Are supervector spaces the representations of a Hopf algebra?

Different definitions of the dimension of an algebra

What are the Schur functions of the eigenvalues of a non-negative integer matrix counting?

Poisson algebras as deformations vs. Poisson algebras in algebraic topology

Direct construction of the Stone-Čech compactification using ultrafilters?

Where does Segal's category come from?

Is the Zariski density proof of Cayley-Hamilton circular?

Obstructions to the existence of stable (and unstable?) complex structures?

Is there a "deep" reason that the first Perrin pseudoprime is large?

Frobenius elements from the point of view of étale fundamental groups

Reference request: probability / ergodic theory without measure spaces

Iterating monoid categories

Combinatorial proof of (a special case of) the spectral theorem?