Skip to main content
Search type Search syntax
Tags [tag]
Exact "words here"
Author user:1234
user:me (yours)
Score score:3 (3+)
score:0 (none)
Answers answers:3 (3+)
answers:0 (none)
isaccepted:yes
hasaccepted:no
inquestion:1234
Views views:250
Code code:"if (foo != bar)"
Sections title:apples
body:"apples oranges"
URL url:"*.example.com"
Saves in:saves
Status closed:yes
duplicate:no
migrated:no
wiki:no
Types is:question
is:answer
Exclude -[tag]
-apples
For more details on advanced search visit our help page
Results tagged with
Search options not deleted user 83

Hamiltonian systems, symplectic flows, classical integrable systems

6 votes

To what extent can I think of a Lagrangian fibration in a symplectic manifold as T*N?

Hey Theo --- I don't think it is reasonable to expect Lagrangian fibrations to be cotangent bundles globally. Easy example: take a 2d torus, give it a symplectic form (equivalently a volume form in t …
Kevin H. Lin's user avatar
8 votes
Accepted

Clarification of classical field theory lecture notes by P. Deligne and D. Freed

Configuration space is, by definition, the position space of your particles. Phase space, on the other hand, is the space of pairs (position, momentum). The latter has a symplectic structure; the form …
Kevin H. Lin's user avatar
7 votes

Cotangent bundle of a submanifold

Here is an attempt. Let $X$ be a submanifold of $Y$, and let $i : X \to Y$ be the inclusion. In general, we have the exact sequence of vector bundles $$ 0 \to N^\ast X \to i^\ast T^\ast Y \to T^\ast …
Kevin H. Lin's user avatar
4 votes
2 answers
751 views

Convergence of quantum cohomology

For which manifolds or varieties is quantum cohomology known to converge? Are there any manifolds for which quantum cohomology is known to not converge? I seem to have the impression that quantum coho …
Kevin H. Lin's user avatar
0 votes
Accepted

Convergence of quantum cohomology

See Dmitri's comment.
Kevin H. Lin's user avatar
10 votes

Has anything precise been written about the Fukaya category and Lagrangian skeletons?

There are a few comments about this in the notes from Kontsevich's talk (Internet Archive) at the Arbeitstagung (Internet Archive). I also attended the Seidel talk that people are referring to. I shou …
Kevin H. Lin's user avatar
7 votes
2 answers
3k views

Different definitions of Novikov ring?

Following, e.g., Wikipedia's definitions, the (small) quantum cohomology ring of $X$ is defined over a "Novikov ring" consisting of formal power series of the form $$ \sum_{\beta \in H_2(X;\mathbb{Z}) …
Kevin H. Lin's user avatar
16 votes

Examples in mirror symmetry that can be understood.

Here is the simplest example that I can think of... The ordinary cohomology ring of $\mathbb{CP}^n$ is given by $\mathbb{C}[a]/(a^{n+1})$. The structure of this ring can be thought of as describing t …
Kevin H. Lin's user avatar
10 votes
5 answers
1k views

Compact Kaehler manifolds that are isomorphic as symplectic manifolds but not as complex man...

What are some examples of compact Kaehler manifolds (or smooth complex projective varieties) that are not isomorphic as complex manifolds (or as varieties), but are isomorphic as symplectic manifolds …
Kevin H. Lin's user avatar
15 votes
1 answer
3k views

Where does the Givental reconstruction formula come from?

In (for example) Semisimple Frobenius structures at higher genus (section 1.2) and Gromov-Witten invariants and quantization of quadratic Hamiltonians (section 6.8), Givental gives a conjectural formu …
Kevin H. Lin's user avatar
9 votes
2 answers
2k views

Are Fukaya categories Calabi-Yau categories?

Let X be a compact symplectic manifold. There is an idea, I think probably originally due to Kontsevich, that we should be able to get Gromov-Witten invariants of X out of the Fukaya category of X. On …
Kevin H. Lin's user avatar
11 votes
1 answer
2k views

"Fourier-Mukai" functors for Fukaya categories?

I just skimmed a bit of this fresh-off-the-press paper on homological mirror symmetry for general type varieties. One thing that intrigued me was statement (ii) of Conjecture 3.3. It suggests that, j …
Kevin H. Lin's user avatar
14 votes
4 answers
2k views

Negative Gromov-Witten invariants

I understand the heuristic reason why Gromov-Witten invariants can be rational; roughly it's because we're doing curve counts in some stacky sense, so each curve $C$ contributes $1/|\text{Aut}(C)|$ to …
Kevin H. Lin's user avatar
4 votes

Is there an algebraic construction of the Quillen (determinant) Line Bundle?

I hope I'm not getting any details wrong, but I think the Narasimhan-Seshadri theorem asserts that the moduli space of $G=U(n)$ representations of $\pi_1$ is the same as the moduli space $M(n)$ of sem …
Kevin H. Lin's user avatar
16 votes

What is the role of contact geometry in the hamiltonian mechanics?

I think the basic example is when you have a symplectic manifold $M$ with a Hamiltonian $H : M \to \mathbb{R}$. Then take a regular value $a$ of $H$, and look at the hypersurface $N := H^{-1}(a)$, whi …
Kevin H. Lin's user avatar

15 30 50 per page