Institut
de Mathématiques de Luminy

Abstract 2004-9 |

**Troubetzkoy** Serge.

Periodic billiard orbits in right triangles.

There is an open set of right triangles such that for cach irrational triangle in this set (i) periodic billiards orbits are dense in the phase space, (ii) there is a unique nonsingular perpendicular billiard orbit which is not periodic, and (iii) the perpendicular periodic orbits fill the corresponding invariant surface. |