Weyl type theorems for left and right polaroid operators (Q989938)

The authors investigate the equivalences of Weyl type theorems and generalized Weyl type theorems for left and a-polaroid operators. As a consequence, they obtain a general framework which allows them to derive in a unified way many recent results concerning Weyl type theorems for important classes of operators. A bounded operator defined on a Banach space is said to be polaroid if every isolated point of the spectrum is a pole of the resolvent.