´┐╝Domains which are integrable close to the boundary and close to the circular ones are ellipses

Speaker. Ilya Koval
Date. 08.06.22 at 2:00 pm

Abstract. The Birkhoff conjecture says that the boundary of a strictly convex integrable billiard table is necessarily an ellipse. We will consider a stronger notion of integrability, namely integrability close to the boundary, and discuss a local version of this conjecture: a small perturbation of an ellipse of small eccentricity which preserves integrability near the boundary is itself an ellipse.