Where: MTH 1311

Speaker: Vadim Kaloshin (UMCP)

Where: MTH 1308

Title: On Conjugacy of Convex Billiards (joint with A. Sorrentino)

Where: MATH 1308

Speaker: Kelly Funk (University of Illinois at Urbana-Champaign)<br>

Title: On Rigidity Sequences

Abstract: In this talk we will discuss rigidity sequences and uniform rigidity sequences. I will give examples of each for weakly mixing transformations and inform you of what has been done thus far to characterize the structure of these sequences. Then I will prove a generic result regarding weakly mixing homeomorphisms of the two torus that are uniformly rigid and show that if a sequence satisfies a certain growth rate then there is a weakly mixing homeomorphism of the two torus that is uniformly rigid with respect to the given sequence.

Where: MTH 1308

Speaker: Carlos Matheus Silva Santos (Paris 13)

Title: A criterion for the simplicity of the Lyapunov spectrum of square-tiled surfaces (joint with M. Moeller and J.-C. Yoccoz)

Abstract: The Lyapunov exponents of the so-called Kontsevich-Zorich (KZ) cocycle over the Teichmuller geodesic flow are important quantities associated to the study of deviation of ergodic averages of interval exchange transformations, translation flows and billiards. After the seminal works of G. Forni, and A. Avila and M Viana on the so-called Kontsevich-Zorich conjecture, we know that the Lyapunov exponents of KZ cocycle with respect to the natural absolutely continuous (Masur-Veech) probability are simple (i.e., they are non-zero and their multiplicity is 1). On the other hand, G. Forni (and his collaborators) constructed particular examples of probabilities associated to square-tiled surfaces whose Lyapunov spectrum for the KZ cocycle have zero and/or non-simple exponents. In particular, one can ask whether there is a (say, sufficient) criterion to decide the simplicity of the Lyapunov spectrum associated to square-tiled surfaces. In this talk we will discuss a joint work with Martin Moller and Jean-Christophe Yoccoz showing such a simplicity criterion (in the spirit of the work of A. Avila and M. Viana). As a consequence of this simplicity criterion, we will exhibit an infinity family of square-tiled surfaces (of genus 3) of the minimal stratum H(4) meeting the conditions of our simplicity criterion.

Where: MTH 1308

Speaker: Dmitry Dolgopyat, UMCP

Title: Limit theorems for toral translations

Where: MTH 1308

Speaker: Albert Fathi, (ENS Lyon)

Title: Smoothing Lyapunov Functions

Where: MTH 1308

Speaker: Livio Flaminio (Lille)

Title: Flows Cohomologies and equi-distribution

Where: MTH 1308

Speaker: Todd Fisher, BYU

Title: Unique equilibrium states for certain robustly transitive diffeomorphisms

Where: MTH 1308

Speaker: Evelyn Sander, (George Mason University)

Title: Uncovering the Bifurcation Structure of the Diblock Copolymer Model