Séminaires : Séminaire d'Algèbres d'Opérateurs

Equipe(s) : ao,
Responsables :Pierre Fima, François Le Maître, Romain Tessera
Email des responsables :
Salle : 1013
Adresse :Sophie Germain

Orateur(s) Andrei Alpeev - ENS PSL,
Titre Strong Ulam stability and amenability
Horaire14:00 à 15:00
A group is called strongly Ulam-stable if near an almost representation on a Hilbert space (meaning that the homomorphism equality holds up to some error in the norm) there is a close actual unitary representation. Kazhan showed that all amenable groups are strongly Ulam-stable. In the onter direction the best known result, by Burger, Ozawa and Thow, was that every group containing a non-abelian free group is nos strongly Ulam-stable. I will show that lamplighters over non-amenable groups are not strongly Uam-stable.
AdresseSophie Germain