Seminars & Events for Department Colloquium
Open-closed Gromov-Witten theory
Lagrangian Floer theory studies boundary valued problem for the maps from bordered Riemann surface with boundary condition given Lagrangian submanifold. Gromov-Witten theory studies pseudo-holomorphic maps from Riemann surface. Various relations between them is found and is expected to be useful both in symplectic geometry and the study of Mirror symmetry.
Renaissance of the h-principle in symplectic topology
Flexible and rigid methods coexisted in Symplectic Topology since its inception. The developmnet during last 20 years was dominated by rigid results, with accidental flexible breakthroughs (such as Donaldson's theory of almost holomorphic sections). In the talk I will discuss some recently found new remarkable examples of symplectic flexibility.
From the Jones polynomial to Khovanov homotopy
In the early 1980's, Jones introduced a new knot invariant, now called the Jones polynomial. Roughly ten years ago, Khovanov gave a refinement -- or categorification -- of the Jones polynomial; this refinement is now called Khovanov homology. In this talk we will sketch definitions of the Jones polynomial and Khovanov homology, and mention some of their most spectacular applications.
In search of a Langlands transform
Class field theory expresses Galois groups of abelian extensions of a number field F in terms of harmonic analysis on the multiplicative group of locally compact topological ring, the adèle ring, attached to F.
Asymptotics of Eigenvalues and Eigenfunctions in Periodic Homogenization
Understanding asymptotics of eigenvalues and eigenfunctions in homogenization is an important problem and it has attracted a great deal of attentions. One of the practical reasons is that it may be applied in the studies of some inverse problems and problems of uniform boundary controllability.
Categorification at a prime root of unity
Quantization parameter q becomes a grading shift after categorification. When q specializes to a root of unity, categorification becomes more subtle. We'll discuss an approach to categorification at a prime root of unity p via p-differentials in characteristic p.
Derangements
A fixed point free permutation of a set is called a derangement. It is an old result of Jordan that if G is a transitive permutation group on a finite set, then derangements exist. In fact, some anaylsis of this problem predates group theory going back to the early 1700's. PLEASE CLICK ON SEMINAR TITLE FOR COMPLETE ABSTRACT.
Hidden structures in large matrices
Consider the problem of estimating the entries of a large matrix, when most of the entries are either hidden from us or blurred by noise. Of course, one needs to assume that the matrix has some structure for this estimation to be possible. PLEASE CLICK ON COLLOQUIUM TITLE FOR COMPLETE ABSTRACT.
Hydrodynamic turbulence as a problem in non-equilibrium statistical mechanics
The problem of hydrodynamic turbulence is reformulated as a heat flow problem along a chain of mechanical systems which describe units of fluid of smaller and smaller spatial extent. PLEASE CLICK ON COLLOQUIUM TITLE FOR COMPLETE ABSTRACT.
Riemann-Roch for graphs and applications
We will begin by formulating the Riemann-Roch theorem for graphs due to the speaker and Norine. PLEASE CLICK ON COLLOQUIUM TITLE FOR COMPLETE ABSTRACT.
The energy-critical NLS in the exterior of a convex obstacle
We will discuss the induction on energy technique in the study of nonlinear dispersive equations using the problem described in the title as our primary model case. To the extent time allows, we will then
describe some of the new difficulties connected with this particular problem and how they were overcome in recent joint work with Monica Visan and Xiaoyi Zhang.
From Nash to Onsager: funny coincidences across differential geometry and the theory of turbulence
The incompressible Euler equations were derived more than 250 years ago by Euler to describe the motion of an inviscid incompressible fluid. PLEASE CLICK ON COLLOQUIUM TITLE FOR COMPLETE TITLE.
Decay estimates for scalar waves and Maxwell flows on relativistic black hole backgrounds
Decay estimates for wave equations are crucial in the study of a broad range of nonlinear problems. In this talk I will describe recent and ongoing work on such estimates for linear wave equations on relativistic black hole space-times. The emphasis will be both on scalar waves and on spin systems such as the Maxwell equations.
Regularity of Boltzmann equation in convex domains
We establish Sobolev regularity for solutions to the Boltzmann equation in a convex domain with diffuse boundary condition.
Riemannian Hyperbolization
PLEASE CLICK ON COLLOQUIUM TITLE FOR COMPLETE ABSTRACT. The strict hyperbolization process of R. Charney and M. Davis produces a large and rich class of negatively curved spaces (in the geodesic sense).