English

McDuff superrigidity for group II$_1$ factors

Operator Algebras 2025-12-01 v1 Group Theory

Abstract

Developing new techniques at the interface of geometric group theory and von Neumann algebras, we identify the first examples of ICC groups GG whose von Neumann algebras are McDuff and exhibit a new rigidity phenomenon, termed McDuff superrigidity: an arbitrary group HH satisfying L(H)L(G)\mathcal{L}(H)\cong \mathcal{L}(G) decomposes as HG×AH \cong G\times A for an ICC amenable group AA.

Keywords

Cite

@article{arxiv.2511.23123,
  title  = {McDuff superrigidity for group II$_1$ factors},
  author = {Juan Felipe Ariza Mejía and Ionuţ Chifan and Denis Osin and Bin Sun},
  journal= {arXiv preprint arXiv:2511.23123},
  year   = {2025}
}
R2 v1 2026-07-01T07:59:17.599Z