Mon, 27 Apr 2026
13:30
13:30
C1
The Descriptive Set Theory of C*-Algebraic Functors and the Kasparov Product
Austin Shiner
((Mathematical Institute University of Oxford))
Abstract
Descriptive set theory provides a useful framework for studying the complexity of classification problems in operator algebras. In this talk I will discuss how C*-algebras can be encoded as points in a Borel space, and introduce several equivalent parametrizations, including a new one in terms of ideals of a universal C*-algebra. I will then discuss examples of natural classes of C*-algebras that form Borel sets, as well as a parametrization of *-homomorphisms and recent results on the Borelness of certain functors. Time permitting, I will introduce KK-theory and the Kasparov product, and explain a new result showing that the Kasparov product is Borel in a certain appropriate parametrized setting.