English

Separation properties for positive-definite functions on locally compact quantum groups and for associated von Neumann algebras

Operator Algebras 2025-01-28 v2 Quantum Algebra

Abstract

Using Godement mean on the Fourier-Stieltjes algebra of a locally compact quantum group we obtain strong separation results for quantum positive-definite functions associated to a subclass of representations, strengthening for example the known relationship between amenability of a discrete quantum group and existence of a net of finitely supported quantum positive-definite functions converging pointwise to II. We apply these results to show that von Neumann algebras of unimodular discrete quantum groups enjoy a strong form of non-ww^*-CPAP, which we call the matrix ϵ\epsilon-separation property.

Keywords

Cite

@article{arxiv.2309.10046,
  title  = {Separation properties for positive-definite functions on locally compact quantum groups and for associated von Neumann algebras},
  author = {Jacek Krajczok and Adam Skalski},
  journal= {arXiv preprint arXiv:2309.10046},
  year   = {2025}
}

Comments

24 pages, v2 corrects a few typos and adds minor comments. The final version of the paper will appear in Selecta Mathematica