Idempotents dans les algèbres de Banach
Using the holomorphic functional calculus we give a characterization of idempotent elements commuting with a given element in a Banach algebra.
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M. Berkani (1996)
Studia Mathematica
Using the holomorphic functional calculus we give a characterization of idempotent elements commuting with a given element in a Banach algebra.
Nikolai Nikolski (1999)
Annales de l'institut Fourier
In this paper, we begin the study of the phenomenon of the “invisible spectrum” for commutative Banach algebras. Function algebras, formal power series and operator algebras will be considered. A quantitative treatment of the famous Wiener-Pitt-Sreider phenomenon for measure algebras on locally compact abelian (LCA) groups is given. Also, our approach includes efficient sharp estimates for resolvents and solutions of higher Bezout equations in terms of their spectral bounds. The smallest “spectral...
Ali Abkar, Hakan Hedenmalm (1998)
Publicacions Matemàtiques
The lattice of invariant subspaces of several Banach spaces of analytic functions on the unit disk, for example the Bergman spaces and the Dirichlet spaces, have been studied recently. A natural question is to what extent these investigations carry over to analogously defined spaces on an annulus. We consider this question in the context of general Banach spaces of analytic functions on finitely connected domains Ω. The main result reads as follows: Assume that B is a Banach space of analytic functions...
Ky Fan (1982)
Mathematische Zeitschrift
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