English

On Relative Property (T) and Haagerup's Property

Group Theory 2018-02-27 v1 Operator Algebras

Abstract

We consider the following three properties for countable discrete groups Γ\Gamma: (1) Γ\Gamma has an infinite subgroup with relative property (T), (2) the group von Neumann algebra LΓL\Gamma has a diffuse von Neumann subalgebra with relative property (T) and (3) Γ\Gamma does not have Haagerup's property. It is clear that (1) \Longrightarrow (2) \Longrightarrow (3). We prove that both of the converses are false.

Keywords

Cite

@article{arxiv.0906.5363,
  title  = {On Relative Property (T) and Haagerup's Property},
  author = {Ionut Chifan and Adrian Ioana},
  journal= {arXiv preprint arXiv:0906.5363},
  year   = {2018}
}
R2 v1 2026-06-21T13:19:08.851Z