Discrete coactions on <i>C</i>*-algebras

Abstract

Abstract We will consider coactions of discrete groups on C *-algebras and imitate some of the results about compact group actions on C *-algebras. In particular, the crossed product of a reduced coaction ∈ of a discrete amenable group G on A is liminal (respectively, postliminal) if and only if the fixed point algebra of ∈ is. Moreover, we will also consider ergodic coactions on C *-algebras.