Operator Algebra seminar

Speaker:  Rasmus Bryder (KU)

Title: Twisted crossed products over C*-simple groups

Abstract: A twisted C*-dynamical system consists of a C*-algebra, a discrete group and a "twisted" action of the group on the C*-algebra, i.e., the group acts by automorphisms on the C*-algebra in a manner determined by a 2-cocycle of the group into the unitary group of the C*-algebra. Whenever the 2-cocycle (or twist) is trivial, the action is given by a group homomorphism of the group into the automorphism group of C*-algebra. We consider twisted C*-dynamical systems over C*-simple groups (i.e., groups whose reduced group C*-algebra is simple) and how C*-simplicity affects the ideal structure of crossed products over such dynamical systems.