Lipschitzness of *-homomorphisms between C*-metric algebras

Abstract

A C*-metric algebra consists of a unital C*-algebra and a Leibniz Lip-norm on the C*-algebra. We show that if the Lip-norms concerned are lower semicontinuous, then any unital *-homomorphism from a C*-metric algebra to another one is necessarily Lipschitz. It results that the free product of two Lipschitz unital *-homomorphisms between C*-metric algebras coming from *-filtrations is still a Lipschitz unital *-homomorphism.

10 pages. *-homomorphism between C*-metric algebras added to Definition 2.5. An error in Proposition 3.2 is corrected. A few minor improvements elsewhere