" C*-approximation theory has provided the foundation for many of the most important
conceptual breakthroughs and applications of operator algebras. This book systematically …

We consider crossed product II 1 factors M=NσG, with G discrete ICC groups that contain
infinite normal subgroups with the relative property (T) and σ trace preserving actions of G …

We consider amalgamated free product II1 factors M= M 1* BM 2* B… and use
“deformation/rigidity” and “intertwining” techniques to prove that any relatively rigid von …

We present some recent rigidity results for von Neumann algebras (II1 factors) and
equivalence relations arising from measure preserving actions of groups on probability …

We prove that if a countable group $\Gamma $ contains infinite commuting subgroups $ H,
H'\subset\Gamma $ with $ H $ non-amenable and $ H'$“weakly normal” in $\Gamma $, then …

We prove that for any free ergodic probability measure preserving action Γ→(X, μ) of a non-
elementary hyperbolic group, or a lattice in a rank one simple Lie group, the associated …

We prove that any isomorphism θ: M 0≃ M of group measure space II 1 factors,
M_0=L^∞(X_0,\mu_0)\sigma_0G_0, M=L^∞(X,μ)σG, with G 0 an ICC group containing an …

We introduce the notion of L 2-rigidity for von Neumann algebras, a generalization of
property (T) which can be viewed as an analogue for the vanishing of 1-cohomology into the …

R.–Ozawa a montré dans [21] que, pour un groupe cci hyperbolique, le facteur de type II1
associé est solide. En devéloppant une nouvelle approche, qui combine les méthodes de …

We prove that for any group G in a fairly large class of generalized wreath product groups,
the associated von Neumann algebra LG completely" remembers" the group G. More …