Annales Henri Poincaré

, Volume 10, Issue 2, pp 357-375

First online:

Unbounded Orbits for Semicircular Outer Billiard

  • Dmitry DolgopyatAffiliated withDepartment of Mathematics, University of Maryland Email author 
  • , Bassam FayadAffiliated withLaboratoire Analyse, Géométrie et Applications, UMR 7539, Institut Galilée, Université Paris 13


We show that the outer billiard around a semicircle has an open ball escaping to infinity.