Groups acting on products of trees, tiling systems and analytic K-theory

Jason S. Kimberley, Guyan Robertson

Let $T_1$ and $T_2$ be homogeneous trees of even degree $\ge 4$. A BM group $\Gamma$ is a torsion free discrete subgroup of $\aut (T_1) \times \aut (T_2)$ which acts freely and transiti…