Operator Theory Seminar - Pieter Spaas; Mathematics Department; UCLA "Stable decompositions and rigidity for products of countable equivalence relations"

February 23, 2021 - 1:30pm to 2:30pm
via Zoom

Zoom: 935 9593 8832 - 1:30 (CST)

https://uiowa.zoom.us/j/93595938832

Speaker:  Pieter Spaas;  Mathematics Department, UCLA

Title:  Stable decompositions and rigidity for products of countable equivalence relations

Abstract: After discussing the motivation behind the talk and some necessary preliminaries, we will consider the ''stabilization'' of a countable ergodic p.m.p. equivalence relation which is not Schmidt, i.e. admits no central sequences in its full group. Using a new local characterization of the Schmidt property, we show that this always gives rise to a so-called stable equivalence relation with a unique stable decomposition, providing the first non-strongly ergodic such examples. We will also discuss some new structural results for product equivalence relations, which we will obtain using von Neumann algebraic techniques.

PSpaas