G_0-dichotomies

Speaker: 

Andres Caicedo

Institution: 

Boise State University

Time: 

Wednesday, June 2, 2010 - 3:30pm

Location: 

RH 340P

The graph G_0 was introduced by Kechris-Solecki-Todorcevic in the late 90s,
and has since turned into an essential object in descriptive set theory. In
joint work with Richard Ketchersid, we prove a version of the G_0-dichotomy
in models of AD^+. This is then used to establish that the quotient by the
equivalence relation E_0 is a successor of R, a result previously known
under AD_R, but (perhaps surprisingly) not in L(R).

A propagation-of-chaos type result in stochastic averaging

Speaker: 

Professor Richard Sowers

Institution: 

University of Illinois

Time: 

Tuesday, May 25, 2010 - 11:00am

Location: 

RH 306

Stochastic averaging goes back to Khasminskii in the 1960's. The
standard result is that, given a separation of scales, one can find effective dynamics
for slow components. We investigate the motion of two particles in such a system, in
particular in a randomly-perturbed twist map. The nub of the issue
is how two points escape from a 1-1 resonance zone. Results of Pinsky
and Wihstutz indicate that there is a third scale at work, which we can use to study
the escape from resonance.

Finding the Unitary Dual of real reductive groups: a challenging but fascinating problem.

Speaker: 

Alessandra Pantano

Institution: 

UCI

Time: 

Thursday, May 27, 2010 - 2:00pm

Location: 

RH 340P

The theory of unitary representations originated in the past century as a natural evolution of classical Fourier analysis. In spite of the extremely significant contributions made by Langlands, Harish-Chandra and many other mathematicians, the problem of finding \emph{all} the unitary irreducible representations of a real reductive group remains a challenge: to this day, a complete answer is only known for a handful of groups. In this talk, I will describe some recent progress in the field.

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