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Li Yutong's user avatar
Li Yutong's user avatar
Li Yutong's user avatar
Li Yutong
  • Member for 11 years, 3 months
  • Last seen this week
  • New York
49 votes
2 answers
11k views

Is tautological bundle $\mathcal{O}(1)$ or $\mathcal{O}(-1)$?

23 votes
4 answers
8k views

Picard group of product of spaces

20 votes
1 answer
6k views

What is the definition of surjective morphism of schemes?

18 votes
1 answer
4k views

Is every complex (smooth) manifold a scheme?

17 votes
1 answer
2k views

Proper VS. Projective morphism

13 votes
1 answer
4k views

Number of points in the fibre and the degree of field extension

11 votes
1 answer
2k views

Koszul complex of locally free sheaves

11 votes
1 answer
2k views

How do people define flop?

10 votes
2 answers
4k views

Does the fibres being equal dimensional imply flatness?

10 votes
1 answer
3k views

Chern class of ideal sheaf

9 votes
1 answer
1k views

Why the existence of automorphism of varieties makes a functor not being a fine moduli space?

8 votes
1 answer
942 views

Projective morphism defined by linear systems

8 votes
1 answer
1k views

Blowup of $xy-z^2$

8 votes
1 answer
3k views

When is a fully faithful functor an equivalant functor?

7 votes
1 answer
326 views

$X \cong \operatorname{Proj} \oplus_n H^0(X, O(n)) $

7 votes
1 answer
853 views

How to compute Hom in derived category?

7 votes
1 answer
452 views

Derived functor vs. spectral sequence

6 votes
0 answers
261 views

An algebraic Möbius strip

6 votes
1 answer
558 views

Factoring a birational morphism through blowup

6 votes
2 answers
2k views

What is the example of pseudo-effective divisor which is not an effective divisor

6 votes
1 answer
2k views

Neron-Severi group as the image of first Chern class

6 votes
1 answer
5k views

Ramification divisor and Hurwitz formula of higher dimensional varieties

6 votes
2 answers
888 views

Euler character of etale finite cover

6 votes
1 answer
1k views

Why the total space of $\mathcal{O}(K)$ has trivial canonical bundle?

5 votes
1 answer
2k views

Properties of canonical divisor of fibres

5 votes
0 answers
451 views

A fake proof of pull-back of an ample divisor is ample

5 votes
1 answer
607 views

Why the GIT quotient $\mathbb{A}^m//\mathbb G_{m}$ is empty?

5 votes
2 answers
856 views

Two questions about discrete valuation rings of varieties

5 votes
0 answers
285 views

Pullback of simple normal crossing divisors

5 votes
1 answer
664 views

Dimensions of global sections of a divisor and its pullback