English

Asymptotic invariants for fusion algebras associated with compact quantum groups

Operator Algebras 2025-10-31 v2 Quantum Algebra

Abstract

We introduce and study certain asymptotic invariants associated with fusion algebras (equipped with a dimension function), which arise naturally in the representation theory of compact quantum groups. Our invariants generalise the analogous concepts studied for classical discrete groups. Specifically we introduce uniform F\o lner constants and the uniform Kazhdan constant for a regular representation of a fusion algebra, and establish a relationship between these, amenability, and the exponential growth rate considered earlier by Banica and Vergnioux. Further we compute the invariants for fusion algebras associated with % discrete duals of quantum SUq(2)SU_q(2) and SOq(3)SO_q(3) and determine the uniform exponential growth rate for the fusion algebras of all qq-deformations of semisimple, simply connected, compact Lie groups and for all free unitary quantum groups.

Keywords

Cite

@article{arxiv.2502.14081,
  title  = {Asymptotic invariants for fusion algebras associated with compact quantum groups},
  author = {Jacek Krajczok and Adam Skalski},
  journal= {arXiv preprint arXiv:2502.14081},
  year   = {2025}
}

Comments

v2 corrects a few minor points. The final version of the paper will appear in Representation Theory