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.
Continuity of the Drazin inverse II
We study the continuity of the generalized Drazin inverse for elements of Banach algebras and bounded linear operators on Banach spaces. This work extends the results obtained by the second author on the conventional Drazin inverse.
Continuous characters and joint topological spectrum
Continuous homomorphisms of Arens-Michael algebras.
Contractible quantum Arens-Michael algebras
We consider quantum analogues of locally convex spaces in terms of the non-coordinate approach. We introduce the notions of a quantum Arens-Michael algebra and a quantum polynormed module, and also quantum versions of projectivity and contractibility. We prove that a quantum Arens-Michael algebra is contractible if and only if it is completely isomorphic to a Cartesian product of full matrix C*-algebras. Similar results in the framework of traditional (non-quantum) approach are established, at the...
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...
Contributi all'analisi spettrale algebrica
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.
Convergence of vectorial continued fractions related to the spectral seminorm.
Convex combinations of unitaries in -algebras.
Convexity around the Unit of a Banach Algebra
2000 Mathematics Subject Classification: Primary: 46B20. Secondary: 46H99, 47A12.We estimate the (midpoint) modulus of convexity at the unit 1 of a Banach algebra A showing that inf {max±||1 ± x|| − 1 : x ∈ A, ||x||=ε} ≥ (π/4e)ε²+o(ε²) as ε → 0. We also give a characterization of two-dimensional subspaces of Banach algebras containing the identity in terms of polynomial inequalities.
Corrigendum Et Addendum A L'Article "Unite Et Semi-Normes Dans Les Algebres Localement Convexes".
Counterexample on semiradial Banach algebras
Crossed products by Hilbert pro-C*-bimodules
We define the crossed product of a pro-C*-algebra A by a Hilbert A-A pro-C*-bimodule and we show that it can be realized as an inverse limit of crossed products of C*-algebras by Hilbert C*-bimodules. We also prove that under some conditions the crossed products of two Hilbert pro-C*-bimodules over strongly Morita equivalent pro-C*-algebras are strongly Morita equivalent.
Cyclic cohomology of certain nuclear Fréchet algebras and DF algebras
We give explicit formulae for the continuous Hochschild and cyclic homology and cohomology of certain -algebras. We use well-developed homological techniques together with some niceties of the theory of locally convex spaces to generalize the results known in the case of Banach algebras and their inverse limits to wider classes of topological algebras. To this end we show that, for a continuous morphism ϕ: x → y of complexes of complete nuclear DF-spaces, the isomorphism of cohomology groups H...
Cyclic vectors for operator algebras
Decomposition of Positive Projections on C*-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.