Skew-Product for Group-Valued Edge Labellings of Brateli Diagrams

Abstract

We associate a Cantor dynamical system to a non-properly ordered Bratteli diagram. Group valued edge labellings $\lambda$ of a Bratteli diagram $B$ give rise to a skew-product Bratteli diagram $B(\lambda)$ on which the group acts. The quotient by the group action of the associated dynamics can be a nontrivial extension of the dynamics of $B$. We exhibit a Bratteli diagram for this quotient and construct a morphism to $B$ with unique path lifting property. This is shown to be an isomorphism for the dynamics if a property ``loops lifting to loops'' is satisfied by $B(\lambda )\to B$.