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Simon Rose's user avatar
Simon Rose's user avatar
Simon Rose
  • Member for 14 years, 4 months
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56 votes
3 answers
9k views

What are the benefits of viewing a sheaf from the "espace étalé" perspective?

51 votes
3 answers
7k views

What is the purpose of the flat/fppf/fpqc topologies?

32 votes
3 answers
3k views

Is there a nice explanation for this curious fact about cyclic subgroups?

21 votes
1 answer
321 views

How many ways can I factor a matrix (over $\mathbb{Z}$)?

16 votes
1 answer
887 views

Can one determine the dimension of a manifold given its 1-skeleton?

16 votes
0 answers
1k views

How many sporadic simple groups are there, really?

16 votes
3 answers
2k views

How do modular forms of half-integral weight relate to the (quasi-modular) Eisenstein series?

14 votes
0 answers
530 views

Am I missing something about this notion of Mirror Symmetry for abelian varieties?

13 votes
1 answer
2k views

Why isn't the orbifold cohomology of $pt/G$ equal to the cohomology of $BG$?

13 votes
1 answer
628 views

What relations exist among (quasi-) modular forms of different levels?

12 votes
2 answers
2k views

What classes am I missing in the Picard lattice of a Kummer K3 surface?

10 votes
1 answer
2k views

What is the geometry behind psi classes in Gromov-Witten theory?

10 votes
1 answer
290 views

What can we say about tropical maps $\mathbb{P}^1 \to A$ for an Abelian variety $A$?

9 votes
1 answer
277 views

How is the propagator computed on an elliptic curve?

9 votes
3 answers
998 views

Is there an intrinsic way to define the group law on Abelian varieties?

9 votes
1 answer
712 views

How do the rings of level $N$ quasi-modular forms related to the rings of modular forms?

8 votes
1 answer
773 views

To what extent does Poincare duality hold on moduli stacks?

8 votes
3 answers
3k views

Why can we define the moment map in this way (i.e. why is this form exact)?

8 votes
0 answers
395 views

Mirror symmetry for polarized abelian surfaces and Shioda-Inose K3s

7 votes
2 answers
2k views

Is there any literature on multivariable theta functions?

7 votes
1 answer
952 views

Trivial obstructions and virtual fundamental classes

7 votes
2 answers
2k views

What is a good reference (preferably thorough) for the Derived Category of a scheme/orbifold/stack?

6 votes
1 answer
279 views

Does the following operation on modular forms yield something modular?

6 votes
3 answers
3k views

What is this restricted sum of multinomial coefficients?

4 votes
2 answers
759 views

What is a reference for the Hasse-Minkowski classification of indefinite forms?

4 votes
2 answers
841 views

What literature is known about MacMahon's generalized sum-of-divisors function?

4 votes
0 answers
107 views

Is there a nice way to invert this expression?

3 votes
1 answer
314 views

Is there a nice way to write the generating function obtained by taking the quadratic coefficients of another one?

3 votes
2 answers
423 views

Is there a nice generating function proof of the following identity?

3 votes
2 answers
1k views

Is there a lower bound for the computational complexity of the traveling salesman problem?