English

Symmetries of a generic coaction

Quantum Algebra 2007-05-23 v2

Abstract

If B is C*-algebra of finite dimension n>3 then the finite dimensional irreducible representations of the compact quantum automorphism group of B, say G, have the same fusion rules as the ones of SO(3). As consequences, we get (1) a structure result for G in the case where B is a matrix algebra (2) if n>4 then the dual of G is not amenable (3) the fixed point subfactor P^G\subset (B\otimes P)^G has index n and principal graph A_\infty.

Keywords

Cite

@article{arxiv.math/9811060,
  title  = {Symmetries of a generic coaction},
  author = {Teodor Banica},
  journal= {arXiv preprint arXiv:math/9811060},
  year   = {2007}
}

Comments

12 pages, amslatex. v2 contains detailed proofs of the 3 corollaries, to appear in Math. Ann

R2 v1 2026-07-22T18:00:50.705Z