Analytic rings
Application des techniques à la théorie des idéaux d’une algèbre de fonctions holomorphes avec poids
Approximation polynomiale pondérée sur une sous-variété totalement réelle de
Approximation Results in the Strict Topology
A-realcompact spaces.
Relations between homomorphisms on a real function algebra and different properties (such as being inverse-closed and closed under bounded inversion) are studied.
Automatic continuity of biseparating maps
We prove that a biseparating map between spaces of vector-valued continuous functions is usually automatically continuous. However, we also discuss special cases when this is not true.
Beziehungen zwischen Tychonoff-Räumen und ihren Funktionenringen.
can sometimes determine without being realcompact
As usual will denote the ring of real-valued continuous functions on a Tychonoff space . It is well-known that if and are realcompact spaces such that and are isomorphic, then and are homeomorphic; that is determines. The restriction to realcompact spaces stems from the fact that and are isomorphic, where is the (Hewitt) realcompactification of . In this note, a class of locally compact spaces that includes properly the class of locally compact realcompact spaces is exhibited...
Caracterización del anillo de funciones diferenciables de una variedad.
En el presente artículo se expone de modo resumido una caracterización de los anillos de funciones diferenciables de una variedad.
C...-Bounding Sets and Compactness.
C(K) norming subsets of C[0,1]
Closed ideals in locally convex algebras of analytic functions.
Cohomologie différentiable des algèbres de polynômes de leurs localisées ou de leurs complétées, et des variétés
Compact and weakly compact homomorphisms between algebras of differentiable functions.
Many authors have recently studied compact and weakly compact homomorphisms between function algebras. Among them, Lindström and Llavona [2] treat weakly compact continuous homomorphisms between algebras of type C(T) when T is a completely regular Hausdorff space.Llavona asked wether the results in [2] are valid in the case of algebras of differentiable functions on Banach spaces. The purpose of this note is to give an affirmative answer to this question, by proving that weakly compact homomorphisms...
Complemented copies of c0 in C0(Ω).
En esta nota consideramos una clase de espacios topológicos de Hausdorff localmente compactos (Ω) con la propiedad de que el espacio de Banach C0(Ω) de todas las funciones continuas con valores escalares definidas en Ω que se anulan en el infinito, equipado con la norma supremo, contiene una copia de C0 norma-uno complementada, mientras que C (βΩ) contiene una copia de l∞ linealmente isométrica.
Constantes de Grothendieck et fonctions de type positif sur les sphères
Continuous linear right inverses for convolution operators in spaces of real analytic functions
We determine the convolution operators on the real analytic functions in one variable which admit a continuous linear right inverse. The characterization is given by means of a slowly decreasing condition of Ehrenpreis type and a restriction of hyperbolic type on the location of zeros of the Fourier transform μ̂(z).
Countably evaluating homomorphisms on real function algebras
By studying algebra homomorphisms, which act as point evaluations on each countable subset, we obtain improved results on the question when all algebra homomorphisms are point evaluations.
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.
Diameter-preserving maps on various classes of function spaces
Under some mild assumptions, non-linear diameter-preserving bijections between (vector-valued) function spaces are characterized with the help of a well-known theorem of Ulam and Mazur. A necessary and sufficient condition for the existence of a diameter-preserving bijection between function spaces in the complex scalar case is derived, and a complete description of such maps is given in several important cases.