A gentle introduction to type III factors and Connes' Bicentralizer Problem
De Amine Marrakchi
Measure equivalence rigidity for Out(Fn) and dynamical decomposition
De Vincent Guirardel
De Stefaan Vaes
Apparaît dans la collection : Groupes, géométrie et analyse : conférence en l'honneur des 60 ans d'Alain Valette
I present a joint work with Sorin Popa and Dimitri Shlyakhtenko. We prove that under a natural condition, the regular von Neumann subalgebras B of the hyperfinite II1 factor R are completely classified (up to conjugacy by an automorphism of R) by theassociated discrete measured groupoid. We obtain a similar result for triple inclusions of A in B in R, where A is a Cartan subalgebra in R and the intermediate von Neumann algebraB is regular in R. The two key steps in proving these results are the vanishing of the 2-cohomology for cocycle actions of amenable discrete measured groupoids and the approximate vanishing of the 1-cohomology.