English

Some remarks on periodic billiard orbits in rational polygons

Dynamical Systems 2016-09-06 v1

Abstract

A polygon is called rational if the angle between each pair of sides is a rational multiple of π.\pi. The main theorem we will prove is Theorem 1: For rational polygons, periodic points of the billiard flow are dense in the phase space of the billiard flow. This is a strengthening of Masur's theorem, who has shown that any rational polygon has ``many'' periodic billiard trajectories; more precisely, the set of directions of the periodic trajectories are dense in the set of velocity directions §1.\S^1. We will also prove some refinements of Theorem 1: the ``well distribution'' of periodic orbits in the polygon and the residuality of the points qQq \in Q with a dense set of periodic directions.

Keywords

Cite

@article{arxiv.math/9408217,
  title  = {Some remarks on periodic billiard orbits in rational polygons},
  author = {Michael Boshernitzan and G. A. Galperin and Tyll Krüger and Serge Troubetzkoy},
  journal= {arXiv preprint arXiv:math/9408217},
  year   = {2016}
}
R2 v1 2026-07-22T17:55:00.319Z