Dipartimento di Matematica, Università di Genova, Via Dodecaneso 35, 16146 Genova, Italy
Abstract:
This paper deals with the connection between continuity of spectrum at an element of the Banach algebra of all bounded linear operators on a Banach space and at the adjoint of . In particular, we show that, if is not reflexive, the spectrum function may be continuous at and discontinuous at .