User Theo Johnson-Freyd

99 votes

4 answers

16k views

Can every manifold be given an analytic structure?

asked Dec 13, 2009 at 19:44

93 votes

4 answers

9k views

Is there an accepted definition of $(\infty,\infty)$ category?

asked Jun 18, 2013 at 13:59

83 votes

8 answers

23k views

What is the symbol of a differential operator?

asked Oct 30, 2009 at 22:12

59 votes

3 answers

4k views

Is "semisimple" a dense condition among Lie algebras?

asked Dec 24, 2009 at 7:41

47 votes

16 answers

9k views

What does the generating function $x/(1 - e^{-x})$ count?

asked Dec 18, 2009 at 1:44

44 votes

2 answers

3k views

What algebraic group does Tannaka-Krein reconstruct when fed the category of modules of a non-algebraic Lie algebra?

asked Apr 15, 2010 at 4:06

43 votes

6 answers

7k views

What does "quantization is not a functor" really mean?

asked Dec 11, 2009 at 21:23

42 votes

3 answers

3k views

What is the classifying space of "G-bundles with connections"

asked Feb 17, 2010 at 21:05

39 votes

4 answers

3k views

How is tropicalization like taking the classical limit?

asked Oct 13, 2009 at 4:44

39 votes

6 answers

4k views

Examples of applications of the Borel-Weil-Bott theorem?

asked Oct 26, 2009 at 4:45

39 votes

2 answers

3k views

Is there a "quantum" Riemann zeta function?

asked Nov 13, 2010 at 19:43

37 votes

7 answers

8k views

Why is Lie's Third Theorem difficult?

asked Dec 13, 2009 at 19:31

33 votes

9 answers

5k views

Why should I prefer bundles to (surjective) submersions?

asked Mar 11, 2010 at 5:32

32 votes

6 answers

3k views

What should I call a "differential" which cubes, rather than squares, to zero?

asked Mar 24, 2020 at 18:49

30 votes

5 answers

4k views

Can epi/mono for natural transformations be checked pointwise?

asked Mar 12, 2010 at 6:17

29 votes

1 answer

1k views

Is there a symmetric monoidal 2-category "SuperDuperVect"?

asked Jun 19, 2015 at 22:00

28 votes

1 answer

2k views

What's the status of the following relationship between Ramanujan's $\tau$ function and the simple Lie algebras?

asked Dec 24, 2009 at 23:48

27 votes

2 answers

5k views

What's the current state of the classification of not-fully-extended TQFTs?

asked Jul 9, 2010 at 5:35

26 votes

2 answers

2k views

What does the Tannakian formalism reconstruct when fed the category of chain complexes?

asked Nov 13, 2011 at 5:57

25 votes

2 answers

3k views

Is there a good (co)homology theory for manifolds with corners?

asked Feb 1, 2010 at 2:10

25 votes

1 answer

643 views

Has the $E_8$-based generating function for squares numbers been proven?

asked Aug 13, 2018 at 11:17

24 votes

4 answers

2k views

Which is the correct ring of functions for a topological space?

asked Nov 29, 2009 at 1:03

24 votes

5 answers

3k views

Can surfaces be interestingly knotted in five-dimensional space?

asked Jan 20, 2011 at 21:53

23 votes

6 answers

2k views

Is there a topological description of combinatorial Euler characteristic?

asked Oct 19, 2009 at 7:59

23 votes

2 answers

699 views

Does the 3875-dimensional rep of $E_8$ have a solution to $x\star x=0$?

asked Jun 23, 2019 at 16:46

22 votes

1 answer

804 views

Does $E_8$ know $Spin(7)$?

asked Apr 29, 2016 at 16:12

22 votes

3 answers

2k views

What is the precise relationship between groupoid language and noncommutative algebra language?

asked Jul 9, 2010 at 21:07

21 votes

1 answer

2k views

Functoriality of the cotangent bundle

asked Apr 20, 2011 at 0:47

21 votes

3 answers

2k views

Is there a "categorical" description of Grothendieck's algebra of differential operators?

asked Mar 14, 2010 at 19:53

21 votes

2 answers

3k views

Does projective imply flat?

asked Jun 30, 2015 at 16:15

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249 Questions

Can every manifold be given an analytic structure?

Is there an accepted definition of $(\infty,\infty)$ category?

What is the symbol of a differential operator?

Is "semisimple" a dense condition among Lie algebras?

What does the generating function $x/(1 - e^{-x})$ count?

What algebraic group does Tannaka-Krein reconstruct when fed the category of modules of a non-algebraic Lie algebra?

What does "quantization is not a functor" really mean?

What is the classifying space of "G-bundles with connections"

How is tropicalization like taking the classical limit?

Examples of applications of the Borel-Weil-Bott theorem?

Is there a "quantum" Riemann zeta function?

Why is Lie's Third Theorem difficult?

Why should I prefer bundles to (surjective) submersions?

What should I call a "differential" which cubes, rather than squares, to zero?

Can epi/mono for natural transformations be checked pointwise?

Is there a symmetric monoidal 2-category "SuperDuperVect"?

What's the status of the following relationship between Ramanujan's $\tau$ function and the simple Lie algebras?

What's the current state of the classification of not-fully-extended TQFTs?

What does the Tannakian formalism reconstruct when fed the category of chain complexes?

Is there a good (co)homology theory for manifolds with corners?

Has the $E_8$-based generating function for squares numbers been proven?

Which is the correct ring of functions for a topological space?

Can surfaces be interestingly knotted in five-dimensional space?

Is there a topological description of combinatorial Euler characteristic?

Does the 3875-dimensional rep of $E_8$ have a solution to $x\star x=0$?

Does $E_8$ know $Spin(7)$?

What is the precise relationship between groupoid language and noncommutative algebra language?

Functoriality of the cotangent bundle

Is there a "categorical" description of Grothendieck's algebra of differential operators?

Does projective imply flat?