AF Embeddability of the C*-Algebra of a Deaconu-Renault Groupoid

Abstract

We study Deaconu-Renault groupoids corresponding to surjective local homeomorphisms on locally compact, Hausdorff, second countable, totally disconnected spaces, and we characterise when the C*-algebras of these groupoids are AF embeddable. Our main result generalises theorems in the literature for graphs and for crossed products of commutative C*-algebras by the integers. We give a condition on the surjective local homeomorphism that characterises the AF embeddability of the C*-algebra of the associated Deaconu-Renault groupoid. In order to prove our main result, we analyse homology groups for AF groupoids, and we prove a theorem that gives an explicit formula for the isomorphism of these groups and the corresponding K-theory. This isomorphism generalises Farsi, Kumjian, Pask, Sims (M\"unster J. Math, 2019) and Matui (Proc. Lond. Math. Soc, 2012), since we give an explicit formula for the isomorphism and we show that it preserves positive elements.