Previous Conferences & Workshops

Feb
27
2012

Computer Science/Discrete Mathematics Seminar I

An Additive Combinatorics Approach to the Log-Rank Conjecture in Communication Complexity
Noga Zewi
11:15am|S-101

For a {0,1}-valued matrix M let CC(M) denote he deterministic communication complexity of the boolean function associated with M. The log-rank conjecture of Lovasz and Saks [FOCS 1988] states that CC(M) <= log^c(rank(M)) for some absolute constant c where rank(M) denotes the rank of M over the field of real numbers. We show that CC(M) <= c rank(M)/logrank(M) for some absolute constant c, assuming a well-known conjecture from additive combinatorics, known as the Polynomial Freiman-Ruzsa (PFR) conjecture. Our proof is based on the study of the "approximate duality conjecture" which was recently suggested by Ben-Sasson and Zewi [STOC 2011] and studied there in connection to the PFR conjecture. First we improve the bounds on approximate duality assuming the PFR conjecture. Then we use the approximate duality conjecture (with improved bounds) to get the aforementioned upper bound on the communication complexity of low-rank martices, and this part uses the methodology suggested by Nisan and Wigderson [Combinatorica 1995]. This is joint work with Eli Ben-Sasson and Shachar Lovett.

Feb
23
2012

Joint IAS/Princeton University Number Theory Seminar

Modularity Lifting in Non-Regular Weight
David Geraghty
4:30pm|Fine Hall -- 214

Modularity lifting theorems were introduced by Taylor and Wiles and formed a key part of the proof of Fermat's Last Theorem. Their method has been generalized successfully by a number of authors but always with the restriction that the Galois...

Feb
23
2012

Special Computer Science/Discrete Mathematics Lecture

Building Expanders in Three Steps
3:30pm|S-101

The talk will have 2 parts (between the parts we will have a break). In the first part, we will discuss two options for using groups to construct expander graphs (Cayley graphs and Schreier diagrams). Specifically, we will see how to construct...

Feb
23
2012

Special Computer Science/Discrete Mathematics Lecture

Zero Knowledge Proofs and Nuclear Disarmament
1:30pm|S-101

I'll describe a physical implementation of zero knowledge proofs whose goal is to verify that two physical objects are identical, without revealing any information about them. Our motivation is the task of verifying that an about-to-be-dismantled...

Feb
22
2012

Working Group on Symplectic Dynamics

On Translated Points of Contactomorphisms
Sheila Margherita Sandon
4:00pm|S-101

The Arnold conjecture in Symplectic Topology states existence of many fixed points for Hamiltonian symplectomorphisms of a compact symplectic manifold. In my talk I will discuss an analogue of this conjecture in Contact Topology, based on the notion...

Feb
21
2012

Analysis Seminar

Reducibility for the Quasi-Periodic Liner Schrodinger and Wave Equations
Lars Hakan Eliasson
2:30pm|S-101

We shall discuss reducibility of these equations on the torus with a small potential that depends quasi-periodically on time. Reducibility amounts to "reduce” the equation to a time-independent linear equation with pure point spectrum in which case...