English

The Dixmier problem, lamplighters and Burnside groups

Group Theory 2010-01-17 v1 Functional Analysis

Abstract

J. Dixmier asked in 1950 whether every non-amenable group admits uniformly bounded representations that cannot be unitarised. We provide such representations upon passing to extensions by abelian groups. This gives a new characterisation of amenability. Furthermore, we deduce that certain Burnside groups are non-unitarisable, answering a question raised by G. Pisier.

Cite

@article{arxiv.0902.4585,
  title  = {The Dixmier problem, lamplighters and Burnside groups},
  author = {Nicolas Monod and Narutaka Ozawa},
  journal= {arXiv preprint arXiv:0902.4585},
  year   = {2010}
}

Comments

4 pages

R2 v1 2026-06-21T12:15:54.805Z