Abstract:The aim of this paper is to characterize a class of subspectra for which the geometric spectral radius is the same and depends only upon a commuting $n$-tuple of elements of a complex Banach algebra. We prove also that all these subspectra have the same capacity.
Keywords: Banach algebra, joint spectrum, subspectrum, spectroid, geometrical spectral radius, (joint) capacity
AMS Subject Classification: 46H05