English

Von Neumann equivalence and group approximation properties

Operator Algebras 2023-12-29 v1 Group Theory

Abstract

The notion of von Neumann equivalence (vNE), which encapsulates both measure equivalence and WW^*-equivalence, was introduced recently by Jesse Peterson, Lauren Ruth and the author. They showed that many analytic properties, such as amenability, property (T), the Haagerup property, and proper proximality are preserved under von Neumann equivalence. In this article, we expand on the list of properties that are stable under von Neumann equivalence, and prove that weak amenability, weak Haagerup property, and the approximation property (AP) are von Neumann equivalence invariants. In particular, we get that (AP) is stable under measure equivalence. Furthermore, our techniques give an alternate proof for vNE-invariance of the Haagerup property.

Cite

@article{arxiv.2107.11335,
  title  = {Von Neumann equivalence and group approximation properties},
  author = {Ishan Ishan},
  journal= {arXiv preprint arXiv:2107.11335},
  year   = {2023}
}

Comments

9 pages. arXiv admin note: text overlap with arXiv:1910.08682

R2 v1 2026-06-24T04:28:11.881Z