A Gelfand-Type Duality for Coarse Metric Spaces With Property A

Abstract

Abstract We prove the following two results for a given uniformly locally finite metric space with Yu’s property A: 1. The group of outer automorphisms of its uniform Roe algebra is isomorphic to its group of bijective coarse equivalences modulo closeness. 2. The group of outer automorphisms of its Roe algebra is isomorphic to its group of coarse equivalences modulo closeness. The main difficulty lies in the latter. To prove that, we obtain several uniform approximability results for maps between Roe algebras and use them to obtain a theorem about the “uniqueness” of Cartan masas of Roe algebras. We finish the paper with several applications of the results above to concrete metric spaces.