Self-similar groups and topological dimension

Abstract

We give various characterizations of the covering dimension of the limit space of a contracting self-similar group. In particular, we show that it is equal to the minimal dimension of a contracting affine model, to the asymptotic dimension of the orbital graphs of its action on the boundary of the tree, to the dynamical asymptotic dimension of its groupoid of germs, and give a combinatorial description of the dimension in terms of a partition of the levels of the tree. We analyze separately the one-dimensional example. In particular, we show that the limit space is one-dimensional if and only if the group is the faithful quotient of a self-similar contracting virtually free group.