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Théorèmes de structure sur certaines algèbres m-convexes commutatives.

Z. Abdelali, M. Chidami (2000)

Extracta Mathematicae

Nous donnons dans ce travail une caractérisation des algèbres (semi-simples) localement-convexes complètes faiblement topologisées au sens de S. Warner, ce qui clarifie, entre autres, plusiers résultats données sur certaines classes d'algèbres à base étudiées par de nombreux auteurs ([2], [6], [7]) pour approcher le problème de E. A. Michael sur la continuité des caractères dans les algèbres de Fréchet [9].

Theorems of Korovkin type for adapted spaces

Heinz Bauer (1973)

Annales de l'institut Fourier

It is shown that the methods developed in an earlier paper of the author about a Dirichlet problem for the Silov boundary [Annales Inst. Fourier, 11 (1961)] lead in a new and natural way to the most important results about the convergence of positive linear operators on spaces of continuous functions defined on a compact space. Choquet’s notion of an adapted space of continuous functions in connection with results of Mokobodzki-Sibony opens the possibility of extending these results to the case...

Theorems of Krein Milman type for certain convex sets of functions operators

Robert R. Phelps (1970)

Annales de l'institut Fourier

Sufficient conditions are given in order that, for a bounded closed convex subset B of a locally convex space E , the set C ( X , B ) of continuous functions from the compact space X into B , is the uniformly closed convex hull in C ( X , E ) of its extreme points. Applications are made to the unit ball of bounded (or compact, or weakly compact) operators from certain Banach spaces into C ( X ) .

Theorems of the alternative for cones and Lyapunov regularity of matrices

Bryan Cain, Daniel Hershkowitz, Hans Schneider (1997)

Czechoslovak Mathematical Journal

Standard facts about separating linear functionals will be used to determine how two cones C and D and their duals C * and D * may overlap. When T V W is linear and K V and D W are cones, these results will be applied to C = T ( K ) and D , giving a unified treatment of several theorems of the alternate which explain when C contains an interior point of D . The case when V = W is the space H of n × n Hermitian matrices, D is the n × n positive semidefinite matrices, and T ( X ) = A X + X * A yields new and known results about the existence of block diagonal...

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