Groups and Operator Algebras Seminar

Speaker: Sergio Giron Pacheco (University of Oxford)

Title: Anomalous symmetries and invariants of operator algebras

Abstract: An anomalous symmetry of an operator algebra A is a mapping from a group G to the automorphism group of A which is multiplicative up to inner automorphisms. This can be rephrased as the action of a pointed tensor category on A. Anomalous symmetries have been systematically studied and successfully classified in the case that A is an injective factor by Connes, Jones, Katayama, Ocneanu and Takesaki.

Starting from the basics, I will introduce anomalous actions and discuss the history of their study in the literature. I will then discuss their existence and classification questions on C*-algebras. For these questions, it will be important to consider K-theoretic invariants of the algebras.

GOA website: https://sites.google.com/view/copenhagen-goa-seminar