English

Quasi-invariant states for the action of compact groups

Operator Algebras 2025-07-29 v1

Abstract

We analyze a natural C*-algebraic definition of G-quasi-invariant states for the automorphic action of a compact group G. We prove that, given a G-quasi-invariant state with central support, when the action of the group G commutes with the modular group, its GNS representation is equivalent to that of a G-invariant state.

Keywords

Cite

@article{arxiv.2507.20931,
  title  = {Quasi-invariant states for the action of compact groups},
  author = {Maria Elena Griseta},
  journal= {arXiv preprint arXiv:2507.20931},
  year   = {2025}
}