The Canonical Endomorphism for Infinite Index Inclusions

Abstract

We give purely algebraic characterisations of the canonical endomorphism in in-teresting infinite index cases, continuing previous works of Longo and the authors. We apply these results when compact and discrete (but not necessarily finite-dimensional) Woronowicz algebras act alternately on the factors in the various levels of Jones’ tower. We characterise when the acting algebra is a Kac algebra.