Fri Nov 17, 2023
Alexander Kechris (Caltech)
The compact action realization problem
In this talk I will discuss realizations of countable Borel equivalence relations by continuous actions of countable groups, focusing in particular on the problem of realization by continuous actions on compact spaces and more specifically subshifts. This also leads to considering a natural universal space for actions and equivalence relations via subshifts and the study of the descriptive and topological properties in this universal space of various classes of countable Borel equivalence relations, especially the hyperfinite ones.