Looking for a Billiard Table which is not a Lattice Polygon but Satisfies Veech's Dichotomy

Meital Cohen

Published 2010-11-14Version 1

Over the course of studying billiard dynamics, several questions were raised. One of the questions was, which surfaces satisfy the following property (which is called Veech's dichotomy): Any direction is either completely periodic or uniquely ergodic. In an important paper Veech gave a sufficient condition for this dichotomy. He showed that if the stabilizer of a translation surface is a lattice in $SL_2(\R)$, then the surface satisfies Veech's dichotomy. Later, Smillie and Weiss proved that this condition is not necessary. They constructed a translation surface which satisfies Veech's dichotomy but is not a lattice surface. Their construction was based on previous work of Hubert and Schmidt, by taking a branched cover over a lattice surface, where the branch locus is a single non-periodic connection point. In this work we tried to answer the following question: Is there a flat structure obtained from a billiard table that satisfies Veech's dichotomy, but its Veech group is not a lattice? We prove that in the entire list of possible candidates for such a construction, an example does not exist.