Current Seminars
updated 4/21/2004

   
APRIL 21 - APRIL 23, 2004
   
Joint Institute for Advanced Study and Princeton University Complex Geometry Seminar
Topic: Crepant Resolutions of Calabi-Yau Orbifolds
Presenter:  Anda Degeratu, Duke University and MSRI
Date:  Wednesday, April 21, 2004, Time: 2:00 p.m., Location: Fine Hall 322
   
Discrete Mathematics Seminar
Topic: Lower Bounds for Degeneracy Testing
Presenter:  Bernard Chazelle, Princeton University
Date:  Wednesday, April 21, 2004, Time: 3:00 p.m., Location: Fine Hall 224
Abstract: I will discuss how to prove lower bounds in a decision tree model for the problem of testing whether out of n numbers k of them sum up to 0. This is joint work with Nir Ailon.
   
Department Colloquium
Topic: Arnold Diffusion
Presenter:  John Mather, Princeton University
Date:  Wednesday, April 21, 2004, Time: 4:30 p.m., Location: Fine Hall 314
   
Ergodic Theory and Statistical Mechanics Seminar
Topic: Universality in Random Matrix Theory for Orthogonal and Symplectic Ensembles (joint work with P.Deift)
Presenter:  Dimitri Gioev, University of Pennsylvania and Courant Institute
Date:  Thursday, April 22, 2004, Time: 2:00 p.m., Location: Fine Hall 322
Abstract: We give a proof of the Universality Conjecture in Random Matrix Theory for orthogonal (beta=1) and symplectic (beta=4) ensembles in the scaling limit for a class of weights w(x)=exp(-V(x)) on the line where V(x) is a polynomial. (For such weights the associated equilibrium measure is supported on a single interval.) Our starting point is Widom's representation of the correlation kernels for the beta=1,4 cases in terms of the unitary (beta=2) correlation kernel plus a correction. In the asymptotic analysis of the correction terms we use amongst other things differential equations for the derivatives of orthogonal polynomials (OP's) due to Tracy-Widom, and uniform Plancherel-Rotach type asymptotics for OP's due to Deift-Kriecherbauer-McLaughlin-Venakides-Zhou. The problem reduces to a small norm problem for a certain matrix of a fixed size that is equal to the degree of the polynomial potential.
   
Topology Seminar
Topic: Small volume cusped hyperbolic three-manifolds
Presenter:  Peter Milley , Princeton University
Date:  Thursday, April 22, 2004, Time: 4:30 p.m., Location: Fine Hall 314
Abstract: This talk will discuss a project of myself, David Gabai, and Robert Meyerhoff to develop a unifying theory to reveal the structure of low volume cusped and closed hyperbolic 3-manifolds.  We will detail preliminary results in the cusped case.
   
Geometric Analysis Seminar
Topic: Critical points of holomorphic sections and string/M theory vacua
Presenter:  Steve Zelditch, Johns Hopkins University
Date:  Friday, April 23, 2004, Time: 3:00 p.m., Location: Fine Hall 314
Abstract: This talk is about joint work with M. R. Douglas and B. Shiffman on statistics of supersymmetric vacua in string theory. Mathematically, it is about the number and location of critical points of holomorphic sections of a hermitian line bundle.  The average number of critical points of a random holomorphic section depends on the metric. In the case of a positive line bundle, Calabi extremal metrics are extremals for the asymptotics of the average number of critical points.
   
APRIL 26 - APRIL 30, 2004
   
Joint Princeton University/Institute for Advanced Study Number Theory Seminar
Topic:

Metaplectic Eisenstein Series and Analytic Continuations of Dirichlet Series

Presenter: 

Ben Brubaker, Stanford University

Date:  Monday, April 26, 2004, Time: 4:00 p.m., Location: Fine Hall 322
Abstract: We will review the definition of Eisenstein series on the metaplectic group and show how they led to the notion of "multiple Dirichlet series," Dirichlet series whose numerator is again a Dirichlet series. We'll look at some interesting examples and new results using the methods of multiple Dirichlet series will be surveyed. Finally, we discuss the broader context of these examples as a result of very recent joint work with Daniel Bump.
   
PACM Colloquium
Topic:

PlanetLab: Introducing Disruptive Technology into the Internet

Presenter: 

Larry Peterson, Computer Science, Princeton University

Date:  Monday, April 26, 2004, Time: 4:00 p.m., Location: Fine Hall 214
Abstract: A new class of geographically distributed network services is emerging, and the most effective way to design, evaluate, and deploy these services is by using an overlay-based testbed. Unlike conventional network testbeds, however, we advocate an approach that supports both researchers that want to develop new services, and clients that want to use them. This dual use, in turn, suggests four design principles that are not widely supported in existing testbeds: services should be able to run continuously and access a slice of the overlay's resources, control over resources should be distributed, overlay management services should be unbundled and run in their own slices, and APIs should be designed to promote application development. This talk describes this high-level vision, and reports the status and plan for the realization of the vision in PlanetLab.
   
Algebraic Geometry Seminar
Topic: TBA
Presenter:  Jaroslaw Wisniewski, Purdue University and Warsaw
Date:  Tuesday, April 27, 2004, Time: 4:30 p.m., Location: Fine Hall 322
   
Mathematical Physics Seminar
Topic: Limit shapes for dimers and complex Burgers equation
Presenter:  Andrei Okounkov, Princeton University
Date:  Tuesday, April 27, 2004, Time: 4:30 p.m., Location: Jadwin A06
   
Department Colloquium
Topic: A deformation of Hodge theory
Presenter:  Jean-Michel Bismut, Universite Paris-Sud
Date:  Wednesday, April 28, 2004, Time: 4:30 p.m., Location: Fine Hall 314
   
Geometric Analysis Seminar
Topic: Moduli spaces of critical Riemannian metrics in dimension 4
Presenter:  Jeff Viaclovsky, MIT
Date:  Friday, April 30, 2004, Time: 3:00 p.m., Location: Fine Hall 314
Abstract: I will discuss some joint work with Gang Tian in which we study the moduli space of anti-self-dual metrics on four-manifolds and also extremal Kahler metrics. We show that, with certain natural geometric assumptions, the moduli space can be compactified by adding metrics with orbifold singularities.
   
MAY 3 - MAY 7, 2004
   
Algebraic Geometry Seminar
Topic: The Enriques conjecture; or, How canonical is the canonical bundle?
Presenter:  Joe Harris, Harvard University
Date:  Tuesday, May 4, 2004, Time: 4:30 p.m., Location: Fine Hall 322
Abstract: The question we're dealing with is this: Is there any way of associating to each smooth curve C of genus g ---or at least to each C in an open subset of moduli---a line bundle on C, other than by taking powers of the canonical bundle? (The answer, by the way, is no: the canonical bundle is truly canonical.) This question was posed almost a century ago; a bogus proof was given by Franchetta in the '40s (as a result of which the statement is usually called Franchetta's conjecture, and a correct proof was given in the '80s by Harer and Mestrano, based on a topological argument of Harer's. In fact, the statement is immediately implied by a stronger conjecture made by Enriques decades earlier. Enriques claimed (or suggested; it's not always clear) an analogous statement for the Severi variety, namely that the only ways of choosing a line bundle on a general plane curve C of degree d and genus g are combinations of the canonical bundle K_C and the hyperplane bundle O_C(1). In this talk I'll discuss a little of the history of the Enriques conjecture, and variants of it; but the main purpose of the talk will be to give a proof of the conjecture that Deepee Khosla and I found recently.
   
Joint Institute for Advanced Study and Princeton University Complex Geometry Seminar
Topic: Singular reduction in special Lagrangian geometry and almost complex geometry
Presenter:  Robert Bryant, Duke University
Date:  Wednesday, May 5, 2004, Time: 2:00 p.m., Location: Fine Hall 322
Abstract: Special Lagrangian manifolds with symmetry can be studied by the method of symplectic reduction, suitably generalized, and this construction yields many of the known examples.  The cohomogeneity one case was essentially completed by Harvey and Lawson in their original paper on calibrated geometries, but the cohomogeneity two case is still not well understood, leading to the study of almost complex curves in almost complex surfaces with singularities. In this talk, after an introductory discussion, the focus will be on some existence and uniqueness questions raised by Dominic Joyce for almost complex curves in the resulting singular spaces.  The resolution of these questions requires the use of techniques from singular PDE that generalize regular singular ODE techniques and these will be introduced and discussed during the talk. Reference: arXiv:math.DG/0402201
   
Geometry, Representation, and Moduli Seminar
Topic: TBA
Presenter: 

Alexander Braverman, Brown University

Date:  Wednesday, May 5, 2004, Time: 3:00 p.m., Location: Fine Hall 214
   
Geometric Analysis Seminar
Topic: Deforming mappings by Mean Curvature Flow
Presenter:  Mao-Pei Tsui, Columbia University
Date:  Friday, May 7, 2004, Time: 3:00 p.m., Location: Fine Hall 314
   
MAY 10 - MAY 14, 2004
   
Joint Princeton University/Institute for Advanced Study Number Theory Seminar
Topic:

TBA

Presenter: 

David J. Burns, King's College, London

Date:  Monday, May 10, 2004, Time: 4:00 p.m., Location: Fine Hall 322
   
Department Colloquium
Topic: Long arithmetic progressions of primes
Presenter:  Ben Green, University of British Columbia
Date:  Wednesday, May 12, 2004, Time: 4:30 p.m., Location: Fine Hall 314
   
MAY 17 - MAY 21, 2004
   
Geometry, Representation, and Moduli Seminar
Topic: TBA
Presenter: 

R. Thomas, Imperial College

Date:  Wednesday, May 19, 2004, Time: 3:00 p.m., Location: Fine Hall 214