An integrable deformation of an ellipse of small eccentricity is an ellipse


The classical Birkhoff conjecture claims that the boundary of a strictly convex integrable billiard table is necessarily an ellipse (or a circle as a special case). In this article we show that a version of this conjecture is true for tables bounded by small perturbations of ellipses of small eccentricity.


Artur Avila

CNRS, IMJ-PRG, UMR 7586, Université Paris Diderot, Sorbonne Paris Cité, Sorbonnes Universités, UPMC Univ Paris 06, Paris, France and IMPA, Rio de Janeiro, Brasil

Jacopo De Simoi

University of Toronto, Toronto, ON, Canada

Vadim Kaloshin

University of Maryland, College Park, MD