We consider operators acting in the space C(X) (X is a compact topological space) of the form $Au\left(x\right)=\left({\sum }_{k=1}^N{e}^{{\phi }_k}{T}_{{\alpha }_k}\right)u\left(x\right)={\sum }_{k=1}^N{e}^{{\phi }_k\left(x\right)}u\left({\alpha }_k\left(x\right)\right)$, u ∈ C(X), where ${\phi }_k\in C\left(X\right)$ and ${\alpha }_k:X\to X$ are given continuous mappings (1 ≤ k ≤ N). A new formula on the logarithm of the spectral radius r(A) is obtained. The logarithm of r(A) is defined as a nonlinear functional λ depending on the vector of functions $\phi ={\left({\phi }_k\right)}_{k=1}^N$. We prove that $ln\left(r\left(A\right)\right)=\lambda \left(\phi \right)=ma{x}_{\nu \in Mes}{\sum }_{k=1}^N{\int }_X{\phi }_{k}d{\nu }_k-\lambda *\left(\nu \right)$, where Mes is the set of all probability vectors of measures $\nu ={\left({\nu }_k\right)}_{k=1}^N$ on X × 1,..., N and λ* is some convex lower-semicontinuous functional on $\left(C^N\left(X\right)\right)*$. In other...

This paper studies properties of a large class of algebras of holomorphic functions with bounded growth in several complex variables.The main result is useful in the applications. Using the symbolic calculus of L. Waelbroeck, it gives for instance a theorem of the “Nullstellensatz” type and approximation theorems.

Let $X$ be a completely regular Hausdorff space, $E$ a real Banach space, and let $C_b(X,E)$ be the space of all $E$-valued bounded continuous functions on $X$. We study linear operators from $C_b(X,E)$ endowed with the strict topologies ${\beta }_z$$(z=\sigma ,...$

Let $X$ be a completely regular Hausdorff space, $C_b\left(X\right)$ the space of all scalar-valued bounded continuous functions on $X$ with strict topologies. We prove that these are locally convex topological algebras with jointly continuous multiplication. Also we find the necessary and sufficient conditions for these algebras to be locally $m$-convex.

Let D (resp. D*) be the subspace of C = C([0,1], R) consisting of differentiable functions (resp. of functions differentiable at the one point at least). We give topological characterizations of the pairs (C, D) and (C, D*) and use them to give some examples of spaces homeomorphic to CDor to CD*.

On étudie les convexes compacts $K$, tels que pour toute partie $A$ de $K$, l’ensemble des fonctions affines continues sur $K$, comprises entre 0 et 1, et nulles sur $A$, ait un plus grand élément. On caractérise ces convexes compacts comme ceux dont des quotients affines convenables sont des chapeaux universels de cônes à base compacte. On a une “complémentation naturelle” sur le treillis des faces exposés de $K$, et des liens remarquables entre ce treillis et l’espace des fonctions affines continues sur $K$.

Soient $E$ un e.v.t., $F$ un sous-espace de $E$, $f$ une fonction analytique de $\mathbf{C}$ dans $E$, telle que $F$ contienne l’image de ${\mathbf{C}}^{*}$. On cherche les valeurs que $f$ peut prendre en zéro puis on fait la liaison entre ce problème et un problème de prolongement analytique.