Geometry and Topology Seminar 2019-2020

Fall 2010

The seminar will be held in room B901 of Van Vleck Hall on Fridays from 1:20pm - 2:10pm

date	speaker	title	host(s)
September 10	Yong-Geun Oh (UW Madison)	Counting embedded curves in Calabi-Yau threefolds and Gopakumar-Vafa invariants	local
September 17	Leva Buhovsky (U of Chicago)	On the uniqueness of Hofer's geometry	Yong-Geun
September 24	Leonid Polterovich (Tel Aviv U and U of Chicago)	Poisson brackets and symplectic invariants	Yong-Geun
October 22	Markus Banagl (U. Heidelberg)	TBA	Maxim
November 5	Sergei Tabachnikov (Penn State)	TBA	Gloria

Abstracts

Yong-Geun Oh (UW Madison)

Counting embedded curves in Calabi-Yau threefolds and Gopakumar-Vafa invariants

Gopakumar-Vafa BPS invariant is some integer counting invariant of the cohomology of D-brane moduli spaces in string theory. In relation to the Gromov-Witten theory, it is expected that the invariant would coincide with the `number' of embedded (pseudo)holomorphic curves (Gopakumar-Vafa conjecture). In this talk, we will explain the speaker's recent result that the latter integer invariants can be defined for a generic choice of compatible almost complex structures. We will also discuss the corresponding wall-crossing phenomena and some open questions towards a complete solution to the Gopakumar-Vafa conjecture.

Leva Buhovsky (U of Chicago)

On the uniqueness of Hofer's geometry

In this talk we address the question whether Hofer's metric is unique among the Finsler-type bi-invariant metrics on the group of Hamiltonian diffeomorphisms. The talk is based on a recent joint work with Yaron Ostrover.

Leonid Polterovich (Tel Aviv U and U of Chicago)

Poisson brackets and symplectic invariants

Markus Banagl (U. Heidelberg)

TBA

Sergei Tabachnikov (Penn State)

TBA