Ramanujan Complexes of any Affine Type

COMPUTER SCIENCE/DISCRETE MATH 1
Topic:Ramanujan Complexes of any Affine Type
Speaker:Donald Cartwright
Affiliation:University of Sydney
Date:Tuesday, December 20
Time/Room:10:30am - 12:30pm/S-101

Ramanujan complexes of type ${\tilde A}_n$ have been constructed by Lubotzky, Samuels and Vishne. In this talk I would like to propose a definition of Ramanujan complexes associated with buildings of any affine type. This involves defining appropriate adjacency operators, studying their properties such as commutativity and describing their joint spectrum.