BIRS Workshop Lecture Videos

Banff International Research Station Logo

BIRS Workshop Lecture Videos

An Ornstein-Weiss-Rokhlin lemma for free actions with the small boundary property Szabo, Gabor


For free actions of amenable groups, we discuss an equivalent characterization of the small boundary property in terms of the existence of disjoint open towers with Folner shapes, small diameters, and the remainder having small orbit capacity. An ingredient behind this, which might be of independent interest, is a characterization of the small boundary property as having a special kind of extension on a totally disconnected space. We pose the question of whether this result can be strengthened for the remainder of the towers to be small in a stronger sense, and relate this to a desirable outcome for transformation group C*-algebras. If time permits, we may discuss actions of groups with the Tempelman condition, or possible applications for embeddings into cubical shifts. This is joint work in progress with David Kerr.

Item Media

Item Citations and Data


Attribution-NonCommercial-NoDerivatives 4.0 International