Gabor Elek (University of Lancaster)
Title: Uniform Borel Amenability
Time: Thursday, 01.05.2024, 16:15.
Place: ELTE, D3-306.
Abstract: According to the classical result of Ornstein and Weiss, if a countable amenable group has a Borel action on the standard Borel set, then for
all quasi-invariant measure mu the associated equivalence relation is mu-hyperfinite. A little bit later Connes-Feldman-Weiss extended this result
for arbitrary "amenable actions". In the talk I will introduce uniform Borel amenability.
and show how to strengthen the results of Ornstein-Weiss and Connes-Feldman-Weiss in the uniform Borel amenable case. Note that Borel actions
of countable amenable groups are uniformly Borel amenable. I will explain all the necessary notions. This is joint work with Adam Timar.