Aperiodic dynamical inclusions of $C^*$-algebras

Abstract

We define the local multiplier module of a Hilbert module in analogy to the local multiplier algebra for C ˚-algebras. We use properties of the local multiplier module to lift non-closed actions on C ˚-algebras by Hilbert bimodules to closed actions on local multiplier algebras, and descend known results on such closed actions down to their unclosed counterparts. We define aperiodic dynamical inclusions and characterise them as crossed products by inverse semigroup actions. We describe the slice structure for such inclusions and show that all slices arise as linear combinations of slices already present in the inverse semigroup action.