Geometry and Topology Seminar 

 Spring 2008

Time/Location: Fridays 1:20pm/901 Van Vleck Hall

Schedule of talks:

WebCalendar Announcements

 

TIME  SPEAKER TITLE HOST
January 25 
Fri, 1:20pm 
 No seminar 
(see Colloquium by Professor Westerland
() 
N/A
February 1 
Fri, 1:20pm 
No seminar 
() 
N/A
February 8 
Fri, 1:20pm 
Hsian-Hua Tseng 
(UW-Madison) 
On orbifold Hodge numbers and orbifold Chern numbers N/A
February 15 
Fri, 1:20pm 
Junwu Tu 
(UW-Madison) 
Hochschild cohomology of Matrix Factorizations N/A
February 22 
Fri, 1:20pm 
Brett Parker 
(MIT) 
Counting Holomorphic curves using the exploded category Oh
February 29 
Fri, 1:20pm 
Peter Albers 
(Courant Institute, NYU) 
A non-displaceable Lagrangian torus in T*S^2 Oh
March 7 
Fri, 1:20pm 
Yat Sun Poon 
(UC Riverside) 
Weak Mirror Symmetry of Nilmanifolds Kalafat
March 14 
Fri, 1:20pm 
No seminar 
(due to spring break) 
() 
N/A
March 28 
Fri, 1:20pm 
Aissa Wade 
 (Penn State University)
Stability of singular points of Poisson manifolds Mari-Beffa
April 04 
Fri, 1:20pm 
Kevin Costello 
(Northwestern U.) 
Calculations of categorical Gromov-Witten invariants Westerland
April 11 
Fri, 1:20pm 
Craig Westerland 
(UW-Madison) 
Vanishing in string topology N/A
April 18 
Fri, 1:20pm 
Christian Haesemeyer 
(UIC) 
K-theory and Hochschild homology of singularities 
(Cancelled due to illness) 
Westerland
April 25 
Fri, 1:20pm 
Yong-Geun Oh 
(UW-Madison) 
(Also note Colloquium by Professor Terng) 
Mirror symmetry of Fano toric A-model and Landau-Ginzburg B-model N/A
May 2 
Fri, 1:20pm 
Noah Kieserman 
(UW-Madison) 
The Liouville phenomenon in the deformation problem of coisotropics N/A
May 5 
Mon, 1:20pm 
Jake Solomon 
(Princeton University) 
Differential equations for open Gromov-Witten invariants Oh

Abstracts

(Tseng): In this talk we will present an identity that equates certain expression of orbifold Hodge numbers and certain expression of orbifold Chern numbers. This generalizes a theorem of Libgober and Woods.

(Tu): We compute the Hochschild cohomology of An A-infinity algebra whose derived category is the derived category of Matrix Factorizations. It turns out that it is the Jacobi ring of the potential function.

(Parker):

(Albers): Leonid Polterovich exhibited a beautiful Lagrangian torus in T*S^2 and asked if this torus is Hamiltonianly displaceable. In joint work with Urs Frauenfelder we prove that the Lagrangian Floer homology does not vanish, indeed equals the singular homology of the torus. In particular, this gives a negative answer to Polterovich's question. In the talk I will describe the construction of the Lagrangian torus and present the computation of the Lagrangian Floer homology which is based on an symmetry argument.
This talk does not assume detailed familiarity with Floer homology.

(Poon): It is well known that given a complex structure J on a manifold M there is a differential Gerstenhaber algebra DGA(M, J). Similarly, given a symplectic structure \omega, there is a differential Gerstenhaber algebra DGA(N, \omega). They form a weak mirror pair if DGA(M, J) and DGA(N, \omega) are quasi-isomorphic. In this talk, we provide a preliminary report on a complete description of weak mirror pairs of six-dimensional nilmanifolds.

(Wade): Let M be a smooth finite-dimensional manifold. Every Poisson structure on M gives rise to a natural foliation of M whose leaves are symplectic manifolds (possibly of different dimensions). A leaf L of a Poisson structure on M is stable if every nearby Poisson structure admits a nearby leaf L', which is diffeomorphic to L.
In this talk, we discuss stability of symplectic leaves of a Poisson structure. Of particular interest is the case of zero-dimensional leaves, called singular points. We will give sufficient conditions for stability of singular points. We will provide some examples for Poisson manifolds of dimension less than 5.

(Costello): To a Calabi-Yau category one can associate a two dimensional field theory, satisfying axioms similar to those of Gromov-Witten theory. The partition function of this theory is the analog of the generating function for Gromov-Witten invariants. For example, the partition function of the derived category of coherent sheaves on a Calabi-Yau manifold is conjectured to be the same as the generating function for the Gromov-Witten invariants of the mirror. This talk will describe an algorithm for calculating the partition function associated to any Calabi-Yau category.

(Westerland): This is a report on work in progress with Nathalie Wahl. We'll define string topology operations for classifying spaces of compact Lie groups (using the work of Chataur-Menichi), study some examples, and sketch a vanishing result in twice the stable range.

(Haesemeyer): Algebraic K-theory is an invariant of rings and varieties that is almost impossible to compute, even for fields. However, it turns out that the so-called Nil K-theory, a direct factor in the K-theory that vanished for regular rings, can be calculated using Hochschild homology. I will try to explain why this is the case, and give some applications.

(Oh): In this talk, I will introduce the notion of weakly unobstructed Lagrangian submanifolds and balanced Lagrangian submanifolds. I will explain construction of certain potential function constructed out of study of deformation theory of Floer cohomology and explain its relationship to the earlier work of Givental which advocates that quantum cohomology ring is isomorphic to the Jacobian ring of Landau-Ginzburg superpotential. I will explain these result in the context of mirror symmetry between Fano toric A-model and Landau-Ginzburg B-model.

(Kieserman): Coisotropic submanifolds have a symplectic aspect, and a foliations aspect. Deformation of foliations is a rather under-determined problem, but the additional symplectic structure allows for computable results. I will talk about my thesis work on computing obstructions in the L-infinity algebra governing this deformation problem, due to Oh & Park. My talk will be very geometric.

(Solomon): I will begin with an overview of open Gromov-Witten theory for 4 and 6 dimensional targets, focusing on the problem of disk enumeration in the projective plane. The solution is given via an open analogue of the WDVV equation. Then I will describe recent work with R. Pandharipande on the open Gromov-Witten theory of the point. Using the open WDVV equation to determine the genus 0 theory of the point, we extrapolate to higher genus and find an open analogue of the KdV hierarchy.


This page is maintained by  Hsian-Hua Tseng
Does the page seem familiar?