Time: 4:40 p.m.
Location: 106 McAllister Building
Name: Rafael Krikorian
Affiliation: Ecole Polytechnique
Title: Herman's last geometric theorem
Abstract: M. Herman announced at various occasions the following striking generalization of J. Moser's invariant curve theorem: a smooth diffeomorphism of a compact surface with the intersection property, leaving invariant a curve on which the dynamics has diophantine rotation number, has infinitely many invariant curves covering a set of positive Lebesgue measure. Moreover, if in the neighborhood of the invariant curve the diffeomorphism has only a finite number of periodic points, then there exists an annulus on which the dynamics of the diffeomorphism is conjugated to a rigid rotation. The remarkable feature of the theorem is that no torsion assumption is needed.
