APRIL 14- APRIL 16, 2004 |
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| Discrete Mathematics Seminar | |
| Topic: | Learning in Groups |
| Presenter: | Robert Calderbank , Princeton University |
| Date: | Wednesday, April 14, 2004, Time: 3:00 p.m., Location: Fine Hall 224 |
| Abstract: | This talk starts by connecting the design of speading sequences in wireless systems with finite geometry and quantum error correction. It explains the linearity of celebrated families of non-linear codes, including the Kerdock and Preparata Codes, and provides a new description of these codes. We also discuss how the new description can be used to generate concise descriptions of massive data sets. |
| Ergodic Theory and Statistical Mechanics Seminar | |
| Topic: | Modulational stability of cellular flows |
| Presenter: | Alexei Novikov, Penn State University. |
| Date: | Thursday, April 15, 2004, Time: 2:00 p.m., Location: Fine Hall 322 |
| Abstract: | We investigate stability of the initial modulational perturbations of stationary solutions to the two-dimensional Navier-Stokes equations with a time-independent periodic rapidly oscillating forcing. The stationary solutions are cellular flows and they are determined by the stream function $\phi = \sin x_1/\epsilon \sin x_2/\epsilon + \delta\cos x_1/\epsilon \cos x_2/\epsilon$, $0 \leq \delta \leq 1$. The perturbations satisfy the modulation equation. For small Reynolds number we determine the stability for the fully nonlinear modulation equation. For any Reynolds number we determine the stability of the linearized modulation equation. |
| Ergodic Theory and Statistical Mechanics Seminar - *** Please note special time and location | |
| Topic: | Linear and sub-linear behavior of random walks in random environments on a strip |
| Presenter: | Ilya Goldsheid, Queen Mary, University of London |
| Date: | Thursday, April 15, 2004, Time: 4:30 p.m., Location: Fine Hall 601 |
| Abstract: | The remarkable fact that a transitive random walks in random environment does not necessarily grow linearly but may also exhibit sub linear behavior has been known since 1975 (Solomon; Kesten-Kozlov-Spitser). These results were proved for the case of the simplest random walk in dimension one. The attempts to establish similar results for other cases had a limited success. I shall discuss necessary and sufficient conditions leading to a relatively full description of this sort of behavior for a wide range of one- and quasi one-dimensional models. |
| Special Algebra Seminar | |
| Topic: | Mordell-Weil Lattices and Modular Forms |
| Presenter: | Tetsuji Shioda, Rikkyo University. |
| Date: | Thursday, April 15, 2004, Time: 4:30 p.m., Location: Fine Hall 322 |
| Bill Browder Birthday Topology Seminar Doubleheader - Note special times | |
| Topic: | Representations and K-Theory of the Braid Group |
| Presenter: | Alejandro Adem, University of Wisconsin |
| Date: | Thursday, April 15, 2004, Time: 3:00 p.m., Location: Fine Hall 314 |
| Topic: | Enlargeability and Index Theory |
| Presenter: | Bernhard Hanke, Universitat Muenchen |
| Date: | Thursday, April 15, 2004, Time: 4:30 p.m., Location: Fine Hall 314 |
| Abstact: | Let M be a smooth, compact enlargeable spin manifold. Independently of the Baum-Connes conjecture, we prove nonvanishing of a universal index obstruction associated witn M. This implies the result by Gromov and Lawson that M does not admit a metric of positive scalar curvature. As an application of our methods we show that the map --> B\pi_1(M) classifying the universal cover of M sends the fundamental homology class of M to a non trivial class in H_*(B\pi_1(M); Q. This answers a question of D. Burghelea (1983). |
| Joint Columbia University/Courant Institute/Princeton University Differential Geometry Seminar | |
| Topic: | Geometry and topology of multiple product spaces |
| Presenter: | Mikhail Gromov, Courant Institute |
| Date: | Friday, April 16, 2004, Time: 3:00 p.m., Location: Columbia University, Room Math 520 |
| Joint Columbia University/Courant Institute/Princeton University Differential Geometry Seminar | |
| Topic: | Witten's conjecture and property P |
| Presenter: | Tom Mrowka, MIT |
| Date: | Friday, April 16, 2004, Time: 4:30 p.m., Location: Columbia University, Room Math 520 |
APRIL 19 - APRIL 23, 2004 |
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| Special Analysis Seminar | |
| Topic: | A solution of periodic 1 dimensional Nonlinear Shrodinger Equation with polynomial growth of Sobolev Norms and diffusion in high dimensional Hamiltonian systems |
| Presenter: | Vadim Kaloshin, Caltech |
| Date: | Monday, April 19, 2004, Time: 4:00 p.m., Location: Fine Hall 314 |
| Joint Princeton University/Institute for Advanced Study Number Theory Seminar | |
| Topic: | TBA |
| Presenter: | Harald Helfgott, Yale University |
| Date: | Monday, April 19, 2004, Time: 4:00 p.m., Location: Fine Hall 322 |
| Algebraic Geometry Seminar | |
| Topic: | TBA |
| Presenter: | Mikhail Kapranov, Yale University |
| Date: | Tuesday, April 20, 2004, Time: 4:30 p.m., Location: Fine Hall 322 |
| 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 |
| 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. |
APRIL 26 - APRIL 30, 2004 |
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| 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 |
| 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 |
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| 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 |
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| 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 |
MAY 17 - MAY 21, 2004 |
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| 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 |