English

Cocycle superrigidity for coinduced actions

Operator Algebras 2015-12-02 v1 Dynamical Systems

Abstract

We prove a cocycle superrigidity theorem for a large class of coinduced actions. In particular, if Λ\Lambda is a subgroup of a countable group Γ\Gamma, we consider a probability measure preserving action ΛX0\Lambda\curvearrowright X_0 and let ΓX\Gamma\curvearrowright X be the coinduced action. Assume either that Γ\Gamma has property (T) or that Λ\Lambda is amenable and Γ\Gamma is a product of non-amenable groups. Using Popa's deformation/rigidity theory we prove ΓX\Gamma\curvearrowright X is Ufin\mathcal U_{fin}-cocycle superrigid, that is any cocycle for this action to a Ufin\mathcal U_{fin} (e.g. countable) group V\mathcal V is cohomologous to a homomorphism from Γ\Gamma to V.\mathcal V.

Keywords

Cite

@article{arxiv.1512.00093,
  title  = {Cocycle superrigidity for coinduced actions},
  author = {Daniel Drimbe},
  journal= {arXiv preprint arXiv:1512.00093},
  year   = {2015}
}
R2 v1 2026-06-22T11:58:08.874Z