Action moyennable d'un groupe localement compact sur une algèbre de von Neumann II.

Abstract

This is the continuation of our previous work on amenable actions of a locally compact group G on a von Neumann algebra M. We study stability properties of this notion of amenable action by extension and restriction. We also prove that an action of G on M is amenable if and only if the corresponding action of G on the centre Z(M) is amenable. Then we give applications to the study of injectivity of crossed products.