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Yosemite Sam
  • Member for 10 years, 10 months
  • Last seen more than 3 years ago
22 votes
3 answers
3k views

how to make the category of chain complexes into an $\infty$-category

18 votes
1 answer
2k views

can a common mortal understand why the affine line is not smooth in brave new algebraic geometry?

14 votes
2 answers
2k views

what is the stringy Kähler moduli space?

11 votes
1 answer
1k views

coarse moduli space and $\pi_0$

11 votes
3 answers
1k views

Reference for the derived category of $X$, $[X/G]$ and $X/G$

9 votes
1 answer
3k views

surjective morphism of schemes or epimorphism of sheaves?

7 votes
1 answer
1k views

What is the negative cyclic homology of a smooth projective variety?

5 votes
0 answers
207 views

Description of flop as graded algebra

5 votes
1 answer
627 views

Resolutions by free Differential Graded Algebras

4 votes
1 answer
607 views

Colimits in colimits of categories

4 votes
0 answers
420 views

where to learn K-group of coherent sheaves modulo numerical equivalence?

4 votes
2 answers
703 views

If $f: X \to Y$ is a finite flat morphism of schemes, $g: Y \to Z$ is a proper morphism of relative dimension one, $Z$ is affine and $E$ is a vector bundle on $Y$ with $R^1g_*E=0$ then $H^1(X,f^*E)=0$?

4 votes
1 answer
412 views

can one define the pullback between stacks of coherent sheaves for non-flat morphisms?

3 votes
2 answers
1k views

if f is birational, is the pushforward map on the numerical groups surjective?

3 votes
1 answer
290 views

uniqueness of uniformizers

2 votes
1 answer
282 views

Is the pushforward via a proper map of a finite presentation module of finite presentation?

2 votes
1 answer
288 views

If tensor product has finite length, do higher Tors also have finite length?

2 votes
0 answers
248 views

Can I recognize the quotient of a group by a closed subgroup? (for example the standard representation of S3 in GL(2,C))

2 votes
1 answer
580 views

Does Hom(X,Spec R) = Hom(R, O(X)) hold for algebraic stacks?

1 vote
1 answer
244 views

If X -> Y -> X is the identity and Y is of finite type, can I say anything about X?

0 votes
0 answers
112 views

Books on algebraic groups over C with examples [duplicate]