Continuité et uniforme continuité du spectre dans les algèbras de Banach
Continuity of a homomorphism on commutative subalgebras is not sufficient for continuity
Continuity of characters in products of algebras
Continuity of derivations from radical convolution algebras
Continuity of derivations on semi-prime Banach algebras.
Continuity of generalized inverses in Banach algebras
The main topic of the paper is the continuity of several kinds of generalized inversion of elements in a Banach algebra with identity. We introduce the notion of asymptotic generalized invertibility and completely characterize sequences of elements with this property. Based on this result, we derive continuity criteria which generalize the well known criteria from operator theory.
Continuity of Jordan homomorphisms of Banach algebras.
Continuity of spectrum and spectral radius in algebras of operators
Continuity of spectrum and spectral radius in Banach algebras
This survey deals with necessary and/or sufficient conditions for continuity of the spectrum and spectral radius functions at a point of a Banach algebra.
Continuous characters and joint topological spectrum
Continuous homomorphisms of Arens-Michael algebras.
Contractive projections and Seever’s identity in complex -algebras
In this paper we give necessary and sufficient conditions in order that a contractive projection on a complex -algebra satisfies Seever’s identity.
Contribuciones al análisis funcional no-standard.
En este trabajo presentamos aportaciones al tratamiento no-standard del Análisis Funcional en dos direcciones. En la sección 2 la envoltura no-standard de un espacio vectorial topológico, introducida por Luxemburg [7] y por Henson y Moore [2] se aplica al caso de un álgebra topológica. En las secciones 3 y 4 se dan caracterizaciones de elementos accesibles (pre-near-standard) y casi-standard (near-standard) en espacios vectoriales topológicos en términos de una familia filtrante densa de subespacios...
Convergence in the generalized sense relative to Banach algebras of operators and in LMC-algebras
The notion of convergence in the generalized sense of a sequence of closed operators is generalized to the situation where the closed operators involved are affiliated with a Banach algebra of operators. Also, the concept of convergence in the generalized sense is extended to the context of a LMC-algebra, where it applies to the spectral theory of the algebra.
Corrigendum Et Addendum A L'Article "Unite Et Semi-Normes Dans Les Algebres Localement Convexes".
Counterexample on semiradial Banach algebras
Cyclic vectors for operator algebras
Décompositions dans certaines algèbres de Fréchet de fonctions holomorphes.
Dans ce travail, nous étudions le problème de décomposicion suivant: Étant donnés deux ouverts bornés de Cp, Ω1 et Ω2 (vérifiant certaines conditions) et étant donnée une matrice A(z), carrée d'ordre n, dont les coefficients sont des fonctions holomorphes dans Ω1 ∩ Ω2, ayant une prolongement C∞ à l'adhérence (Ω1 ∩ Ω2), peut-on trouver deux matrices A1(z), A2(z) holomorphes dans Ω1 et Ω2 respectivement et se prolongeant de manière C∞ à (Ω1) et (Ω2) telles que sur Ω1 ∩ Ω2 on aitA = A1A2.
Derivations, Commutators and the Radical.
Derivations mapping into the socle, III
Let A be a Banach algebra, and let d: A → A be a continuous derivation such that each element in the range of d has a finite spectrum. In a series of papers it has been proved that such a derivation is an inner derivation implemented by an element from the socle modulo the radical of A (a precise formulation of this statement can be found in the Introduction). The aim of this paper is twofold: we extend this result to the case where d is not necessarily continuous, and we give a complete description...