Square Turning Maps and their Compactifications

Abstract

In this paper we introduce some infinite rectangle exchange transformations which are based on the simultaneous turning of the squares within a sequence of square grids. We will show that such noncompact systems have higher dimensional dynamical compactifications. In good cases, these compactifications are polytope exchange transformations based on pairs of Euclidean lattices. In each dimension $8m+4$ there is a $4m+2$ dimensional family of them. Here $m=0,1,2,...$ The case $m=0$, which we studied in depth in an earlier paper, has close connections to the $E_4$ Weyl group and the $(2,4,\infty)$ hyperbolic triangle group.