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Theo Johnson-Freyd's user avatar
Theo Johnson-Freyd's user avatar
Theo Johnson-Freyd's user avatar
Theo Johnson-Freyd
  • Member for 16 years, 5 months
  • Last seen more than a week ago
99 votes
4 answers
16k views

Can every manifold be given an analytic structure?

93 votes
4 answers
9k views

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

83 votes
8 answers
23k views

What is the symbol of a differential operator?

59 votes
3 answers
4k views

Is "semisimple" a dense condition among Lie algebras?

47 votes
16 answers
9k views

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

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?

43 votes
6 answers
7k views

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

42 votes
3 answers
3k views

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

39 votes
4 answers
3k views

How is tropicalization like taking the classical limit?

39 votes
6 answers
4k views

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

39 votes
2 answers
3k views

Is there a "quantum" Riemann zeta function?

37 votes
7 answers
8k views

Why is Lie's Third Theorem difficult?

33 votes
9 answers
5k views

Why should I prefer bundles to (surjective) submersions?

32 votes
6 answers
3k views

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

30 votes
5 answers
4k views

Can epi/mono for natural transformations be checked pointwise?

29 votes
1 answer
1k views

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

28 votes
1 answer
2k views

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

27 votes
2 answers
5k views

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

26 votes
2 answers
2k views

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

25 votes
2 answers
3k views

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

25 votes
1 answer
643 views

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

24 votes
4 answers
2k views

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

24 votes
5 answers
3k views

Can surfaces be interestingly knotted in five-dimensional space?

23 votes
6 answers
2k views

Is there a topological description of combinatorial Euler characteristic?

23 votes
2 answers
699 views

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

22 votes
1 answer
804 views

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

22 votes
3 answers
2k views

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

21 votes
1 answer
2k views

Functoriality of the cotangent bundle

21 votes
3 answers
2k views

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

21 votes
2 answers
3k views

Does projective imply flat?

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