We describe a construction which yields unbounded derivations

and strongly continuous one-parameter automorphism groups of certain

group C*-algebras. As an application, we show that a simple C*-algebra can

have an automorphism...

We provide a new proof of a previously known result, namely every (not necessarily complete) algebra norm on a JB*-algebra generates a topology stronger than the one of the JB*-norm. As a consequence, if θ is a homomorphisrn of a JB*-algebra A...

In this note we show that any derivation of a simple C*-algebra,

whose range is not dense, is closable. We also derive a necessary and sufficient condition

for a *-derivation of a C*-algebra, which is defined on the domain of a closed...

operator algebras...

Le K be a (commutative) locally compact hypergroup with a left Haar measure. Let L1(K) be the hypergroup algebra of K and UCl(K) be the Banach space of bounded left uniformly continuous complex- valued functions on K. In this paper we show, amoung...

We show ¯rst that for each C*-algebra A, contractibility of A implies

contractibility of Mn(A).

We next prove that an incidence algebra A of upper triangular matrices, de¯ned by a

partially ordered set ­ on f1; 2; : : : ; ng...

In this note we review briefly the subject of bounded and unbounded derivations

of operator algebras (C?-and W?-algebras). In particular, we mention some results on closability

and continuity of such derivations. This is an invitation...

It is known that a C * -algebra A is amenable if and only if U(A), the unitary group of A, is amenable. We show the same result for A * -algebras with bounded unitary group and we prove in general that any amenable A * -algebras has amenable unitary...