SEMINARS
Updated: 11-29-2006
   
NOVEMBER 2006
   
Sato-Tate Seminar
Topic: Arithmetic geometry of the Dwork family
Presenter: Nicholas Katz, Princeton University
Date:  Wednesday, November 29, 2006, Time: 1:30 p.m., Location: Fine 314
   
Discrete Mathematics Seminar
Topic: Global connectivity from local conditions
Presenter: David Galvin, University of Pennsylvania
Date:  Wednesday, November 29, 2006, Time: 2:15 p.m., Location: Fine 224
Abstract: See http://www.math.princeton.edu/~bsudakov/galvin2006-fall.pdf
   
Geometry, Representation Theory, and Moduli Seminar
Topic: Quantum cohomology of Hilbert scheme of points of A_n resolutions II
Presenter: Alexei Oblomkov, Princeton University
Date:  Wednesday, November 29, 2006, Time: 3:00 p.m., Location: Fine 214
   
Department Colloquium
Topic: Zeros of L-functions and ranks of Selmer groups
Presenter: Chris Skinner, Princeton University
Date:  Wednesday, November 29, 2006, Time: 4:30 p.m., Location: Fine 314
Abstract: It has long been recognized that certain `special' zeros of L-functions (motivic, automorphic, pick your favorite flavor) have an arithmetic significance. For example, the order of the zero of the Dedekind zeta function of a number field is equal to the rank of the group of units of the integer ring of this field (so the fact that the Riemann zeta function does *not* vanish at s=0 reflects the fact that the units of the integers are a finite group). Similarly, the order of vanishing at s=1 of the L-function of an elliptic curve over the rationals is expected to be the rank of the group of rational points on the curve. In this talk I will describe some recent efforts to provide theoretical evidence for this expectation and its generalizations to other L-functions.
   
Ergodic Theory and Statistical Mechanics Seminar
Topic: On stochastic properties of billiards and on tagged particle diffusion in the 1d Rayleigh gas
Presenter: Peter Balint, Budapest University of Technology and Economics
Date:  Thursday, November 30, 2006, Time: 2:00 p.m., Location: Fine 401
Abstract: In this talk I would like to consider stochastic phenomena arising in various classical mechanical systems. The first part of the talk is meant to give an overview on some recent progress related to ergodic and statistical properties of hyperbolic billiards (joint works with Sebastien Gouezel, Pavel Bachurin and Imre Peter Toth). The second part describes some new observations on tagged particle diffusion in the 1d Rayleigh gas (joint result with Balint Toth and Imre Peter Toth).
   
Institute for Advanced Study and Princeton University Number Theory Seminar
Topic: Sieve methods for Quantum Unique Ergodicity and general shifted sums
Presenter: Roman Holowinsky, IAS
Date:  Thursday, November 30, 2006, Time: 4:30 p.m., Location: Fine 214
Abstract: In this talk, I shall introduce a sieve method for bounding the average size of shifted convolution summation terms related to the Quantum Unique Ergodicity Conjecture for a fixed Hecke-Maass cusp form. This bound will be uniform in the spectral parameter provided that standard bounds hold for the symmetric square and symmetric fourth power L-functions at the point s=1. We shall see that the sieve method can be applied to a wide variety of shifted sums, including sums with multiple shifts.
 
Topology Seminar
Topic: A combinatorial definition of Heegaard-Floor homology for links
Presenter: Dylan Thurston, Columbia University and Barnard College
Date:  Thursday, November 30, 2006, Time: 4:30 p.m., Location: Fine 314
Abstract: We give a completely combinatorial definition and proof of invariance of Heegaard-Floer homology for links in the 3-sphere. The definition is based on a grid-link presentation of the link, also known as an arc presentation. In particular, this yields a simple algorithm for computing the knot genus. If time permits, we will describe how to extract invariants of Legendrian and transverse links in this homology. Parts of this talk are work of Manolescu, Ozsváth, and Sarkar, and parts are joint work with Manolescu, Ozsváth, and Szabó.
   
DECEMBER 2006
   
Differential Geometry and Geometric Analysis Seminar
Topic: TBA
Presenter: Mario Bonk, University of Michigan
Date:  Friday, December 1, 2006, Time: 3:00 p.m., Location: Fine 314
   
PACM Colloquium - Distinguished Lecture Series
Topic: Genomic Information: Biology and Medicine in the 21st Century
Presenter: Eric S. Lander, Broad Institute, Massachusetts Institute of Technology
Date:  Friday, December 1, 2006, Time: 8:00 p.m., Location:A02 McDonnell Hall
Abstract: The Human Genome Project was just an early step in a decades-long scientific program aimed at achieving a systematic and comprehensive view of biology and medicine. This program involves deep collaboration among biologists, chemists, physicians, engineers and -- importantly -- mathematicians and computer scientists. The lecture will describe current projects in genomic medicine, including comparative genomics, human genetics, cancer genetics and chemical biology. Along the way, it will highlight analytical issues that arise from the massive amounts of genomic information that are rapidly becoming available.
   
Analysis Seminar
Topic: Global Well-Posedness for the $L2$-critical NLS in higher dimensions
Presenter: Natasa Pavlovic, Princeton University
Date:  Monday, December 4, 2006, Time: 4:00 p.m., Location: Fine 110
Abstract: In this talk we will present a joint work with Daniela De Silva, Gigliola Staffilani and Nikolaos Tzirakis on global well-posedness for the $L^{2}$ critical NLS in ${\mathbb R}^n$ with $n \geq 3$. Inspired by a recent paper of Fang and Grillakis, we combine the method of almost conservation laws with a local in time Morawetz estimate to improve global well-posedness results in higher dimensions.
   
Algebraic Geometry Seminar
Topic: TBA
Presenter: Günter Harder, Max Planck Institut für Mathematik; IAS
Date:  Tuesday, December 5, 2006, Time: 4:30 p.m., Location: Fine 322
   
Operations Research and Financial Engineering Seminar
Topic:

Stability of utility-maximization in incomplete markets

Presenter: Gordan Zitkovic, University of Texas
Date:  Tuesday, December 5, 2006, Time: 4:30 p.m., Location: E-219, E-Quad
Abstract: The effectiveness of utility-maximization techniques for portfolio management relies on our ability to estimate correctly the parameters of the dynamics of the underlying financial assets. In the setting of complete or incomplete financial markets, we investigate whether small perturbations of the market coefficient processes lead to small changes in the agent's optimal behavior derived from the solution of the related utility-maximization problems. Specifically, we identify the topologies on the parameter process space and the solution space under which utility-maximization is a continuous operation, and we provide a counterexample showing that our results are best possible, in a certain sense. A novel result about the structure of the solution of the utility-maximization problem where prices are modeled by continuous semimartingales is established as an offshoot of the proof of our central theorem.
   
Department Colloquium
Topic: Blow ups of complex solutions of 3D-Navier-Stokes system and Renormalization Group Method.
Presenter: Yakov Sinai, Princeton University
Date:  Wednesday, December 6, 2006, Time: 4:30 p.m., Location: Fine 314
Abstract: In this talk I shall explain the following result of Dong Li and mine:there exists an open set in the space of 10-parameter families of initial conditions such that for each family from this set there are values of parameters such that the corresponding solution develops blow up in finite time.
   
Ergodic Theory and Statistical Mechanics Seminar
Topic: Concentration Inequalities for Dependent Random Variables via the Martingale Method
Presenter: Leonid Kontorovich, School of Computer Science, Carniegie Mellon
Date:  Thursday, December 7, 2006, Time: 2:00 p.m., Location: Fine 401
Abstract:

We use the martingale method to establish concentration inequalities for a class of dependent random sequences on a countable state space, with the constants in the inequalities expressed in terms of certain mixing coefficients. Along the way, we obtain bounds on certain martingale differences associated with the random sequences, which may be of independent interest. As an application of our result, we also derive a concentration inequality for inhomogeneous Markov chains, and establish an extremal property associated with their martingale difference bounds. This work complements certain concentration inequalities obtained by Marton and Samson, while also providing a different proof of some known results. Paper written with Kavita Ramanan. http://arxiv.org/abs/math.PR/0609835

   
Institute for Advanced Study and Princeton University Number Theory Seminar
Topic: Periods and relative trace formulas for GL(2) in the local setting
Presenter: Brooke Feigon, IAS
Date:  Thursday, December 7, 2006, Time: 4:30 p.m., Location: Fine Hall 214
   
Topology Seminar
Topic: On the contact class in Heegaard Floer homology
Presenter: William H. Kazez, University of Georgia
Date:  Thursday, December 7, 2006, Time: 4:30 p.m., Location: Fine 314
Abstract: In joint work with Ko Honda and Gordana Matic, we present an alternate description of the Ozsv\'ath-Szab\'o contact class in Heegaard Floer homology. Using this description, we prove that if a contact structure $(M,\xi)$ has an adapted open book decomposition whose page $S$ is a once-punctured torus, then the monodromy is right-veering if and only if the contact structure is tight.
   
Differential Geometry and Geometric Analysis Seminar
Topic: TBA
Presenter: Bruce Kleiner, Yale University
Date:  Friday, December 8, 2006, Time: 3:00 p.m., Location: Fine 314
   
Analysis Seminar
Topic: TBA
Presenter: Enno Lenzman, MIT
Date:  Monday, December 11, 2006, Time: 4:00 p.m., Location: Fine 110
   
Algebraic Geometry Seminar
Topic: TBA
Presenter: Brendan Hassett, Rice University
Date:  Tuesday, December 12, 2006, Time: 4:30 p.m., Location: Fine 322
   
Discrete Mathematics Seminar
Topic: TBA
Presenter: Tom Bohman, Carnegie Mellon University
Date:  Wednesday, December 13, 2006, Time: 2:15 p.m., Location: Fine 224
   
Geometry, Representation Theory, and Moduli Seminar
Topic: TBA
Presenter: M. Aganagic, Berkeley
Date:  Wednesday, December 13, 2006, Time: 3:00 p.m., Location: Fine 214
   
Department Colloquium
Topic: Trees, elliptic operators, and K-theory for group C*-algebra
Presenter: Paul Baum, Penn State University
Date:  Wednesday, December 13, 2006, Time: 4:30 p.m., Location: Fine 314
Abstract: Let G be a locally compact Hausdorff second countable topological group. Examples are Lie groups, discrete groups, p-adic groups and adelic groups. The regular representation of G gives rise to a C* algebra known as the reduced C* algebra of G. Twenty five years ago P.Baum and A.Connes conjectured an answer to the problem of calculating the K-theory of this C* algebra. When true, this conjecture has corollaries in various branches of mathematics. Among these corollaries are the Novikov conjecture (topology) and the stable Gromov-Lawson-Rosenberg conjecture (differential geometry). In essence, the conjecture asserts that every element in the K-theory of the reduced C* algebra of G is the index of some G-equivariant elliptic operator, and that the only relations on these indices are the "obvious" index preserving relations. This is made precise by using the universal example for proper actions of G. In low dimensions this universal example is a tree. Due to the work of a number of mathematicians, the conjecture is now known to be true for certain classes of groups (e.g. connected Lie groups, discrete hyperbolic groups, discrete a-t-menable groups, algebraic p-adic groups, algebraic adelic groups). The search for a counter-example (to a somewhat generalized version of the conjecture) has led to some intriguing questions involving the expander graphs of Lubotzky-Sarnak and a random group (which probably exists) of Gromov. The talk is intended for a general mathematical audience. The basic definitions (C* algebra, K-theory etc) will be carefully stated in the talk.
   
Ergodic Theory and Statistical Mechanics Seminar
Topic: Finiteness results for Veech groups
Presenter: Barak Weiss, Ben Gurion University
Date:  Thursday, December 14, 2006, Time: 2:00 p.m., Location: Fine 401
Abstract: Veech groups are stabilizers of flat surfaces which arise in the study of billiards on rational polygons and Teichmuller theory. These are discrete subgroups of SL(2,R) which could be lattices but might not be (they are sometimes infinitely generated!), and are the topic of lots of recent research. I will describe work with John Smillie in which we characterize the Veech groups which are lattices from 3 points of view: the dynamics of the straight flow on the flat surface (Veech dichotomy and its variants); the dynamics of the associated flows on the moduli space of flat surfaces; the geometry of the flat surface. We also provide new restrictions in case the groups are not lattices.
   
Topology Seminar
Topic: TBA
Presenter: Saul Schleimer, Rutgers University
Date:  Thursday, December 14, 2006, Time: 4:30 p.m., Location: Fine 314