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On Hamel bases in Banach spaces

Juan Carlos Ferrando — 2014

Studia Mathematica

It is shown that no infinite-dimensional Banach space can have a weakly K-analytic Hamel basis. As consequences, (i) no infinite-dimensional weakly analytic separable Banach space E has a Hamel basis C-embedded in E(weak), and (ii) no infinite-dimensional Banach space has a weakly pseudocompact Hamel basis. Among other results, it is also shown that there exist noncomplete normed barrelled spaces with closed discrete Hamel bases of arbitrarily large cardinality.

On Pettis integrability

Juan Carlos Ferrando — 2003

Czechoslovak Mathematical Journal

Assuming that ( Ω , Σ , μ ) is a complete probability space and X a Banach space, in this paper we investigate the problem of the X -inheritance of certain copies of c 0 or in the linear space of all [classes of] X -valued μ -weakly measurable Pettis integrable functions equipped with the usual semivariation norm.

On the convergence of certain sums of independent random elements

Juan Carlos Ferrando — 2002

Commentationes Mathematicae Universitatis Carolinae

In this note we investigate the relationship between the convergence of the sequence { S n } of sums of independent random elements of the form S n = i = 1 n ε i x i (where ε i takes the values ± 1 with the same probability and x i belongs to a real Banach space X for each i ) and the existence of certain weakly unconditionally Cauchy subseries of n = 1 x n .

A note on copies of c 0 in spaces of weak* measurable functions

Juan Carlos Ferrando — 2000

Commentationes Mathematicae Universitatis Carolinae

If ( Ω , Σ , μ ) is a finite measure space and X a Banach space, in this note we show that L w * 1 ( μ , X * ) , the Banach space of all classes of weak* equivalent X * -valued weak* measurable functions f defined on Ω such that f ( ω ) g ( ω ) a.e. for some g L 1 ( μ ) equipped with its usual norm, contains a copy of c 0 if and only if X * contains a copy of c 0 .

Complemented copies of c in C(Ω).

En esta nota consideramos una clase de espacios topológicos de Hausdorff localmente compactos (Ω) con la propiedad de que el espacio de Banach C(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 C norma-uno complementada, mientras que C (βΩ) contiene una copia de l linealmente isométrica.

Embedding c 0 in bvca ( Σ , X )

Juan Carlos FerrandoL. M. Sánchez Ruiz — 2007

Czechoslovak Mathematical Journal

If ( Ω , Σ ) is a measurable space and X a Banach space, we provide sufficient conditions on Σ and X in order to guarantee that b v c a ( Σ , X ) , the Banach space of all X -valued countably additive measures of bounded variation equipped with the variation norm, contains a copy of c 0 if and only if X does.

A revised closed graph theorem for quasi-Suslin spaces

Juan Carlos FerrandoJ. KąkolM. Lopez Pellicer — 2009

Czechoslovak Mathematical Journal

Some results about the continuity of special linear maps between F -spaces recently obtained by Drewnowski have motivated us to revise a closed graph theorem for quasi-Suslin spaces due to Valdivia. We extend Valdivia’s theorem by showing that a linear map with closed graph from a Baire tvs into a tvs admitting a relatively countably compact resolution is continuous. This also applies to extend a result of De Wilde and Sunyach. A topological space X is said to have a (relatively countably) compact...

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