# Séminaires : Séminaire de Logique Lyon-Paris

 Equipe(s) : lm, Responsables : O. Finkel, A. Khélif, S. Rideau, T. Tsankov, A. Vignati Email des responsables : Salle : Zoom ID: 824 8220 9628; s'inscrire à la liste ou contacter silvain.rideau@imj-prg.fr pour le mot de passe. Adresse : Description

 Orateur(s) Konstantin Slutsky - Équipe de logique mathématique, IMJ-PRG, Titre Séance annulée - Smooth orbit equivalence of free Borel $R^d$ actions. Date 30/03/2020 Horaire 16:00 à 17:30 Diffusion Résume Smooth Orbit Equivalence (SOE) is an orbit equivalence relation between free $R^d$ flows which acts as diffeomorphism between orbits.  This concept originated in ergodic theory of $R$ flows under the name of time change equivalence, where it is closely connected with the concept of Kakutani equivalence of induced transformations.  When viewed from the ergodic theoretical viewpoint, SOE has a rich structure in dimension one, but, as discovered by Rudolph, all ergodic measure preserving $R^d$ flows, $d > 1$, are SOE.     Miller and Rosendal initiated the study of this concept from the point of view of descriptive set theory, where phase spaces of flows aren't endowed with any measures.  This significantly enlarges the class of potential orbit equivalences, and they proved that all non trivial free Borel $R$ flows are SOE.  They posed a question of whether the same remains to be true in dimension $d>1$.  In this talk we answer their question in the affirmative, and show that all non trivial Borel $R^d$ flows are SOE. Salle Zoom ID: 824 8220 9628; s'inscrire à la liste ou contacter silvain.rideau@imj-prg.fr pour le mot de passe. Adresse