Torsten Ekedahl's user avatar
Torsten Ekedahl's user avatar
Torsten Ekedahl's user avatar
Torsten Ekedahl
  • Member for 14 years, 2 months
54 votes

Why worry about the axiom of choice?

48 votes
Accepted

Separable and algebraic closures?

43 votes
Accepted

From Zeta Functions to Curves

34 votes
Accepted

Which groups have only real and quaternionic irreducible representations?

30 votes

Is there a machinery describing all the irreducible representations ?

28 votes
Accepted

Why are normal crossing divisors nice?

28 votes

Symmetric powers and duals of vector bundles in char p

28 votes
Accepted

What do coherent topoi have to do with completeness?

25 votes
Accepted

Which 'well-known' algebraic geometric results do not hold in characteristic 2?

25 votes
Accepted

How does Tate verify his own conjecture for the Fermat hypersurface?

23 votes

The role of completeness in Hilbert Spaces

23 votes

Why does the Grothendieck group $K_0(R)$ of a ring not depend on our choice of using left modules instead of right modules?

22 votes

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

22 votes

"Largest" finite-dimensional Lie subgroups of Diff(S^n), are they known?

21 votes

Is it true that if $\operatorname{Ext}^{1}_{A}(P,A/I)=0 $ for all $ I$ then $P$ is projective?

21 votes

Automorphism group of a scheme

21 votes
Accepted

Chevalley–Shephard–Todd theorem

20 votes
Accepted

What is the wild fundamental group?

20 votes

Orbit structures of conjugacy class set and irreducible representation set under automorphism group

20 votes
Accepted

What about stacks of categories in algebraic geometry?

20 votes

extensions, abelian varieties, $\mathbb{G}_m$

19 votes

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

19 votes
Accepted

Is $Sym^n (V^*) \cong Sym^n (V)^\ast$ naturally in positive characteristic?

19 votes
Accepted

Hilbert 90 for algebras

19 votes
Accepted

Analogue of Smith normal form for matrices over $\mathbb Z[t]$

19 votes
Accepted

Motivic characterization of affine spaces

18 votes

About isogeny theorem for elliptic curves

18 votes

Examples of eventual counterexamples

17 votes

Why torsion is important in (co)homology ?

17 votes

Torsors for finite group schemes

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