Current Seminars
updated 4/24/ 2002
As of April 24 - 26, 2002
Department Colloquium
Topic: A Sampling of the Miracles of Integrability
Presenter: Karen Uhlenbeck, University of Texas at Austin
Date: Wednesday, April 24, 2002, Time: 4:30 p.m., Location: Fine Hall 314
Discrete Mathematics Seminar
Topic: Partitions with bounded components
Presenter: Penny Haxell, University of Waterloo
Date: Thursday, April 25, 2002, Time: 2:00 p.m., Location: Fine Hall 224
Ergodic Theory and Statistical Mechanics Seminar
Topic: TBA
Presenter: Michael Aizenman, Princeton University
Date: Thursday, April 25, 2002, Time: 2:00 p.m., Location: Fine Hall 601
Topology Seminar
Topic: An intersection theory on G_2 manifolds
Presenter: Conan Leung, University of Minnesota
Date: Thursday, April 25, 2002, Time: 4:00 p.m., Location: Fine Hall 314
Princeton University/IAS Number Theory Seminar
Topic: Multiplicities of cusp forms
Presenter: Wee Teck Gan, Princeton University
Date: Thursday, April 25, 2002, Time: 4:30, Location: Fine Hall 322
Graduate Student Seminar
Topic: Weakly Symmetric Spaces
Presenter: Oksana Yakimova, Independent University of Moscow
Date: Friday, April 26, 2002, Time: 1:00, Location: Fine Hall 1001
Abstract: Weakly symmetric spaces were introduced by Selberg in his paper on the trace formula. They have a number of intriguing properties: for instance, any weakly symmetric space is a real form of a complex spherical homogeneous space; then, the algebra of invariant differential operators of a weakly symmetric spaces is always commutative. The classification of weakly symmetric spaces is an open problem. In the talk, I shall speak about some approaches to this problem.
April 29 -May 3, 2002
PACM Colloquium
Topic: The Three Body Problem and Space Mission Design
Presenter: Herb Keller, California Institute of Technology
Date: Monday, April 29, 2002, Time: 4:00 p.m., Location: Fine Hall 214
Abstract: The circular restricted three body problem (CR3BP) of gravitational dynamics governs the motion of satellites near the earth and moon and in many other configurations. The determination of periodic, homoclinic and heteroclinic orbits and indeed unstable orbits of satellites in this configuration is important in mission planning. We show how the code AUTO 2000 has been used to calculate such orbits. A bifurcation diagram showing how most of the known and some new families of periodic orbits are related and connect all the five libration points of the CR3BP. We also treat the new exact three body figure eight solution of Montgomery and Chenciner and show how by reducing the mass of one of the bodies a homotopy to a periodic CR3BP solution results. AUTO is software for continuation and bifurcation of solutions of parameter dependent nonlinear systems of equations. In particular it solves two point boundary value problems with great speed and accuracy. We show how it is adapted to the periodic N-body problem of gravitational dynamics.
CR Seminar
Topic: Flat connections over (Riemann) surfaces
Presenter: William Goldman, University of Maryland
Date: Tuesday, April 30, 2002, Time: 4:00 p.m., Location: Fine Hall 401
Abstract: I will discuss the geometry and symmetry of the moduli space of representations of the fundamental group of a closed oriented surface in a semisimple Lie group. The action of the mapping class group, the symplectic geometry of the moduli space, and the function defined by the energy of the harmonic section of the associated flat bundle of symmetric spaces will be related.
Mathematical Physics Seminar
Topic: Enhanced binding in non-relativistic QED
Presenter: Christian Hainzl, University of Munich
Date: Tuesday, April 30, 2002, Time: 4:30 p.m., Location: Jadwin A06
Abstract: Consider an electron in an external potential V, such that the Schroedinger operator p^2 + V has a ground state. We will show that, as soon as the quantized radiation field is turned on, the binding energy increases. For some short-range potentials V it is even possible that binding occurs, although the corresponding Schroedinger operator does not have an eigenstate. The results presented hold for small values of the coupling parameter alpha, which represents the fine structure constant. Moreover, we will comment on non-perturbative mass-renormalization in the limit of small alpha.
Department Colloquium
Topic: Counting field extensions of the rational numbers
Presenter: Manjul Bhargava, Institute for Advanced Study
Date: Wednesday, May 1, 2002, Time: 4:30 p.m., Location: Fine Hall 314
Abstract: "Number fields" - i.e., finite extensions of the rational numbers - are perhaps the most fundamental objects in algebraic number theory. Yet, amazingly, we have almost no idea how to systematically enumerate them, or even describe their distrbution asympotically with respect to basic invariants. The only general guess on their distribution is an old and simple (but very elusive!) conjecture of Linnik. In this talk, we will state Linnik's conjecture, and present some old and new results that allow for a proof in the case of number fields of degree up to four.
Discrete Mathematics Seminar
Topic: Hook length formula and geometric combinatorics
Presenter: Igor Pak, MIT
Date: Thursday, May 2, 2002, Time: 2:00 p.m., Location: Fine Hall 224
Topology Seminar
Topic: TBA
Presenter: Ko Honda, USC
Date: Thursday, May 2, 2002, Time: 4:00 p.m., Location: Fine Hall 314
Princeton University/IAS Number Theory Seminar
Topic: L and epsilon factors for some representations of GSp(4)
Presenter: Brooks Roberts, University of Idaho
Date: Thursday, May 2, 2002, Time: 4:30, Location: Fine Hall 322
Abstract: In a previous work we proved an analogue for GSp(4) of the dihedral case of the Langlands-Tunnell Theorem. This involved defining some L-packets for GSp(4). In this talk we will discuss the L and epsilon factors associated to the generic elements of these local nonarchimedean L-packets by the Novodvorsky integral representation. We will also discuss the problem of finding canonical vectors in such generic representations which represent their L-factors.
Geometric Analysis Seminar
Topic: Moduli of Hermitian-Yang-Mills connections
Presenter: Gang Tian, MIT
Date: Friday, May 3, 2002, Time: 3:00 p.m., Location: Fine Hall 314
May 6 -May 10, 2002
PACM Colloquium
Topic: TBA
Presenter: Gary O'Dell
Date: Monday, May 6, 2002, Time: 4:00 p.m., Location: Fine Hall 214
Algebraic Geometry Seminar *** Please note special day and time
Topic: Low dimensional representations of finite groups
Presenter: Robert Guralnick, USC
Date: Monday, May 6, 2002, Time: 3:00 p.m., Location: Fine Hall 314
Algebraic Geometry Seminar
Topic: Points of low canonical height on elliptic curves and surfaces
Presenter: Noam Elkies, Harvard University
Date: Tuesday, May 7, 2002, Time: 4:30 p.m., Location: Fine Hall 314
PACM Colloquium *** Please note the special day and time
Topic: Architecture and Dynamics of the Primary Visual Cortex
Presenter: David McLaughlin, Courant Institute of Mathematical Sciences, NYU
Date: Thursday, May 9, 2002, Time: 4:30 p.m., Location: Fine Hall 214