Ulrich Pennig: Equivariant higher twisted K-theory of SU(n) via exponential functors
C*-algebra seminar talk by Ulrich Pennig
The talk will be online, via zoom. Contact Sergey Neshveyev if you want to join.
Title: Equivariant higher twisted K-theory of SU(n) via exponential functors
Abstract: Twisted K-theory is a variant of topological K-theory that allows local coefficient systems called twists. For spaces and twists equipped with an action by a group, equivariant twisted K-theory provides an even finer invariant. Equivariant twists over Lie groups gained increasing importance in the subject due to a result by Freed, Hopkins and Teleman that relates the corresponding K-groups to the Verlinde ring of the associated loop group. From the point of view of homotopy theory only a small subgroup of all possible twists is considered in classical treatments of twisted K-theory. In this talk I will discuss an operator-algebraic model for equivariant higher (i.e. non-classical) twists over SU(n) induced by exponential functors on the category of vector spaces and isomorphisms. These twists are represented by Fell bundles and the C*-algebraic picture allows a full computation of the associated K-groups at least in low dimensions. I will also draw some parallels of our results with the FHT theorem.
This is joint work with D. Evans.