Anton Geraschenko's user avatar
Anton Geraschenko's user avatar
Anton Geraschenko's user avatar
Anton Geraschenko
  • Member for 14 years, 6 months
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291 votes
34 answers
50k views

What are some reasonable-sounding statements that are independent of ZFC?

199 votes
89 answers
52k views

Examples of great mathematical writing

118 votes
5 answers
13k views

What do epimorphisms of (commutative) rings look like?

62 votes
9 answers
23k views

Can a vector space over an infinite field be a finite union of proper subspaces?

61 votes
7 answers
16k views

Is there a measure zero set which isn't meagre?

53 votes
21 answers
19k views

Interesting applications of the pigeonhole principle

41 votes
9 answers
6k views

Is every finite-dimensional Lie algebra the Lie algebra of an algebraic group?

39 votes
4 answers
3k views

Does a scheme have a "separification"?

37 votes
7 answers
4k views

Is an algebraic space group always a scheme?

34 votes
4 answers
11k views

Finite extension of fields with no primitive element

33 votes
4 answers
4k views

What is the universal property of associated graded?

32 votes
6 answers
9k views

What is the universal property of normalization?

32 votes
3 answers
3k views

Wanted: example of a non-algebraic singularity

30 votes
5 answers
3k views

The ants-on-a-ball problem

29 votes
2 answers
10k views

When is fiber dimension upper semi-continuous?

29 votes
5 answers
4k views

Deformation theory of representations of an algebraic group

27 votes
5 answers
9k views

Can a quotient ring R/J ever be flat over R?

26 votes
3 answers
2k views

Is there always a toric isomorphism between isomorphic toric varieties?

25 votes
4 answers
2k views

Does the forgetful functor {Hopf Algebras}→{Algebras} have a right adjoint?

25 votes
4 answers
3k views

Can a conditionally convergent series of vectors be rearranged to give any limit?

25 votes
2 answers
2k views

If the total Chern class of a vector bundle factors, does it have a sub-bundle?

25 votes
4 answers
2k views

algebraic group G vs. algebraic stack BG

24 votes
2 answers
2k views

Is every functor a composition of adjoint functors?

24 votes
4 answers
4k views

When are GIT quotients projective?

23 votes
2 answers
2k views

Does Zariski's Main Theorem come with a canonical factorization?

22 votes
3 answers
830 views

Can continuity of a function be checked by restricting to smooth curves?

20 votes
3 answers
2k views

Can a module be an extension in two really different ways?

20 votes
3 answers
3k views

Is there an additive functor between abelian categories which isn't exact in the middle?

20 votes
3 answers
3k views

How many unit squares can you pack into a rectangle with nearly integer side lengths?

19 votes
6 answers
3k views

What are the most important instances of the "yoga of generic points"?