Séminaires : Séminaire d'Algèbres d'Opérateurs

 Equipe(s) : ao, Responsables : Pierre Fima, François Le Maître, Romain Tessera Email des responsables : Salle : 2015 Adresse : Sophie Germain Description

 Orateur(s) Roman Sauer - Karlsruhe Institute of Technology, Titre Action on Cantor spaces and macroscopic scalar curvature Date 04/02/2021 Horaire 14:00 à 15:00 Diffusion https://bigbluebutton3.imj-prg.fr/b/fra-j6k-9fw Résume We prove the macroscopic cousins of three conjectures: 1) a conjectural bound of the simplicial volume of a Riemannian manifold in the presence of a lower scalar curvature bound, 2) the conjecture that rationally essential manifolds do not admit metrics of positive scalar curvature, 3) a conjectural bound of l2-Betti numbers of aspherical Riemannian manifolds in the presence of a lower scalar curvature bound. The macroscopic cousin is the statement one obtains by replacing a lower scalar curvature bound by an upper bound on the volumes of $1$-balls in the universal cover. Group actions on Cantor spaces surprisingly play an important role in the proof. The talk is based on joint work with Sabine Braun. Salle 2015 Adresse Sophie Germain