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Characterizations of almost transitive superreflexive Banach spaces

Julio Becerra Guerrero, Angel Rodriguez Palacios (2001)

Commentationes Mathematicae Universitatis Carolinae

Almost transitive superreflexive Banach spaces have been considered in [7] (see also [4] and [6]), where it is shown that such spaces are uniformly convex and uniformly smooth. We prove that convex transitive Banach spaces are either almost transitive and superreflexive (hence uniformly smooth) or extremely rough. The extreme roughness of a Banach space X means that, for every element u in the unit sphere of X , we have lim sup h 0 u + h + u - h - 2 h = 2 . We note that, in general, the property of convex transitivity for a Banach...

Continuous version of the Choquet integral representation theorem

Piotr Puchała (2005)

Studia Mathematica

Let E be a locally convex topological Hausdorff space, K a nonempty compact convex subset of E, μ a regular Borel probability measure on E and γ > 0. We say that the measure μ γ-represents a point x ∈ K if s u p | | f | | 1 | f ( x ) - K f d μ | < γ for any f ∈ E*. In this paper a continuous version of the Choquet theorem is proved, namely, if P is a continuous multivalued mapping from a metric space T into the space of nonempty, bounded convex subsets of a Banach space X, then there exists a weak* continuous family ( μ t ) of regular Borel...

Denting point in the space of operator-valued continuous maps.

Ryszard Grzaslewicz, Samir B. Hadid (1996)

Revista Matemática de la Universidad Complutense de Madrid

In a former paper we describe the geometric properties of the space of continuous functions with values in the space of operators acting on a Hilbert space. In particular we show that dent B(L(H)) = ext B(L(H)) if dim H &lt; 8 and card K &lt; 8 and dent B(L(H)) = 0 if dim H &lt; 8 or card K = 8, and x-ext C(K,L(H)) = ext C(K,L(H)).

Dual spaces of compact operator spaces and the weak Radon-Nikodým property

Keun Young Lee (2012)

Studia Mathematica

We deal with the weak Radon-Nikodým property in connection with the dual space of (X,Y), the space of compact operators from a Banach space X to a Banach space Y. First, under the weak Radon-Nikodým property, we give a representation of that dual. Next, using this representation, we provide some applications to the dual spaces of (X,Y) and w * w ( X * , Y ) , the space of weak*-weakly continuous operators.

Dunford-Pettis-like properties of projective and natural tensor product spaces.

Jesús M. Fernández Castillo, Juan A. López Molina (1993)

Revista Matemática de la Universidad Complutense de Madrid

Several properties of weakly p-summable sequences and of the scale of p-converging operators (i.e., operators transforming weakly p-summable sequences into convergent sequences) in projective and natural tensor products with an lp space are considered. The last section studies the Dunford-Pettis property of order p (i.e., every weakly compact operator is p-convergent) in those spaces.

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