Amenability, Kazhdan's property <i>T</i>, strong ergodicity and invariant means for ergodic group-actions
Amenability, Kazhdan's property <i>T</i>, strong ergodicity and invariant means for ergodic group-actions
Abstract This paper discusses the relations between the following properties o finite measure preserving ergodic actions of a countable group G : strong ergodicity (i.e. the non-existence of almost invariant sets), uniqueness of G -invariant means on the measure space carrying the group action, and certain cohomological properties. Using these …