Dia: Dimecres, 17 d'abril de 2024
Lloc: Aula T2 (segon pis), Facultat de Matemàtiques i Informàtica, UB.
A càrrec de: Corentin Fierobe, Institute of Science and Technology Austria (ISTA)
Títol: On the Birkhoff conjecture for nearly centrally symmetric domains
Resum: Perturbations of integrable systems have been intensively studied, mostly from a KAM point of view. There the question is to understand if invariant curves persist after a small perturbation, and which one. Numerous results show that it is true for curves on which the dynamics is conjugated to a rotation of diophantine rotation number. More recent results about so-called integrable billiards and Birkhoffs conjecture underline the importance of invariant curves on which the dynamic is conjugated to a rational rotation when one studies rigidity phenomena of perturbed systems. In the talk we will present a result on invariant curves in an analytic family of twist maps which extends a result by Arnaud, Massetti and Sorrentino in the two-dimensional case, and which can notably be applied to different billiard models. It is the fruit of a joint work with A. Sorrentino.
Last updated: Sun Apr 14 09:38:41 2024