Published online by Cambridge University Press: 24 October 2008
In (1) Akemann and Rosenfeld introduced a property for Banach algebras which they called (*). A Banach algebra satisfies (*) if every maximal one-sided ideal in
is closed. They proved that certain classes of Banach algebra
with
satisfy (*), and they mentioned a conjecture that if
is a Banach algebra with
, then
satisfies (*). In this paper we show that, if
is a Banach algebra with a bounded right (left) approximate identity, then maximal left (right) ideals in
are closed, and we give a counter-example to the above conjecture. We also give an independent proof that C*-algebras satisfy (*).