Previous Conferences & Workshops

Jan
19
2011

Geometry/Dynamical Systems Seminar

Contacting the Moon
Urs Frauenfelder
2:00pm|S-101

The restricted 3-body problem has an intriguing dynamics. A deep observation of Jacobi is that in rotating coordinates the problem admits an integral. In joint work with P. Albers, G. Paternain and O. van Koert, we proved that the corresponding...

Jan
18
2011

Computer Science/Discrete Mathematics Seminar II

Efficiently Learning Mixtures of Gaussians
10:30am|S-101

Given data drawn from a mixture of multivariate Gaussians, a basic problem is to accurately estimate the mixture parameters. We provide a polynomial-time algorithm for this problem for any fixed number ($k$) of Gaussians in $n$ dimensions (even if...

Jan
17
2011

Computer Science/Discrete Mathematics Seminar I

Cross-Validation and Mean-Square Stability
Sergei Vassilvitskii
11:15am|S-101

A popular practical method of obtaining a good estimate of the error rate of a learning algorithm is k-fold cross-validation. Here, the set of examples is first partitioned into k equal-sized folds. Each fold acts as a test set for evaluating the...

Jan
10
2011

Members’ Seminar

Moment-Angle Complexes, Spaces of Hard-Disks and Their Associated Stable Decompositions
Fred Cohen
2:00pm|S-101

Topological spaces given by either (1) complements of coordinate planes in Euclidean space or (2) spaces of non-overlapping hard-disks in a fixed disk have several features in common. The main results, in joint work with many people, give...

Dec
17
2010

Analysis/Mathematical Physics Seminar

Universality and Chaos in Two-Dimensional Classical Ising Spin Glasses
David Huse
2:00pm|S-101

We develop the droplet scaling theory for the low temperature critical behavior of two-dimensional Ising spin glasses. The models with integer bond energies vs. continuously-distributed bond energies are in the same universality class in a regime of...

Dec
16
2010

Joint IAS/Princeton University Number Theory Seminar

Weyl's Sums for Roots of quadratic Congruences
4:30pm|Fine Hall -- 214

It is known that the roots of congruences for a fixed irreducible quadratic polynomial are equidistributed. This statement translates to getting cancellation in the corresponding sum of Weyl's sums. In a recent work by W. Duke, J. Friedlander and H...

Dec
16
2010

Galois Representations and Automorphic Forms Seminar

Two Dimensional Galois Representations Over Imaginary Quadratic Fields
2:15pm|S-101

To a regular algebraic cuspidal representation of GL(2) over a quadratic imaginary field, whose central character is conjugation invariant, Taylor et al. associated a two dimensional Galois representation which is unramified at l different from p...

Dec
15
2010

Galois Representations and Automorphic Forms Seminar

Ramification in Iwasawa Modules
Chandrashekar Khare
2:15pm|S-101

Iwasawa developed his theory for class groups in towers of cyclotomic fields partly in analogy with Weil's theory of curves over finite fields. In this talk, we present another such conjectural analogy. It seems intertwined with Leopoldt's...