Groups and Operator Algebras Seminar

Speaker: Ian Thompson (University of Manitoba).

Title: Hyperrigidity, unitary perturbations, and a non-commutative Šaškin theorem

Abstract: Over the twentieth century, Choquet theory has proven to be a powerful tool in the analysis of compact convex sets and function spaces. In particular, a classical theorem of Šaškin asserts that the Choquet boundary has links to approximation theory. For spaces of Hilbert space operators, several magnificent insights of Arveson and company showcase that a non-commutative Choquet boundary not only exists, but provides a very fruitful analogy. Fifteen years ago, Arveson had conjectured that the non-commutative Choquet boundary also has links to a non-commutative approximation theory. In this talk, we address how unitary perturbations impact Arveson’s conjecture and provide non-commutative variations of Šaškin’s original work.

Zoom link: https://ucph-ku.zoom.us/j/63512030374?pwd=czZvcDU2aTFGeWJKMlRVWkxyOUQ5Zz09

Meeting ID: 635 1203 0374. Passcode: 172793

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