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Strong rigidity of generalized Bernoulli actions and computations of their symmetry groups

Sorin Popa·Stefaan Vaes
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Abstract

We study equivalence relations and II_1 factors associated with (quotients of) generalized Bernoulli actions of Kazhdan groups. Specific families of these actions are entirely classified up to isomorphism of II_1 factors. This yields explicit computations of outer automorphism and fundamental groups. In particular, every finitely presented group is concretely realized as the outer automorphism group of a continuous family of non stably isomorphic II_1 factors.

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Sorin Popa, Stefaan Vaes. 2006-06-23. Strong rigidity of generalized Bernoulli actions and computations of their symmetry groups. https://arxiv.org/abs/math/0605456

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