Proceedings of the Edinburgh Mathematical Society (Series 2)

Research Article

Essentially defined derivations on semisimple Banach algebras

A. R. Villenaa1

a1 Departamento de Análisis Matemático, Universidad de Granada, 18071 Granada, Spain, E-mail address: avillena@goliat.ugr.es

Abstract

We prove that every partially defined derivation on a semisimple complex Banach algebra whose domain is a (non necessarily closed) essential ideal is closable. In particular, we show that every derivation defined on any nonzero ideal of a prime C*-algebra is continuous.

(Received May 31 1995)