On the Intrinsic Group of a Kac Algebra

Abstract

We show that the intrinsic group G(K) of a Kac algebra K can be identified with a particular group of automorphisms of the dual Kac algebra K ⌢ . This enables us to determine the intrinsic group in a few examples, and also to prove that the intrinsic elements do not form a complete set of invariants of a Kac algebra. Finally, we exhibit and study a homomorphism from G(K) into the positive real numbers.