On exhaustive vector measures.
Certain equivalences of Mrowka's separating condition enable us to characterize when parametric maps are open, closed or quotient.
It is well known that some dense subspaces of a barrelled space could be not barrelled. Here we prove that dense subspaces of l∞ (Ω, X) are barrelled (unordered Baire-like or p?barrelled) spaces if they have ?enough? subspaces with the considered barrelledness property and if the normed space X has this barrelledness property. These dense subspaces are used in measure theory and its barrelledness is related with some sequences of unitary vectors.
Si Ω es un conjunto no vacío y X es un espacio normado real o complejo, se tiene que, con la norma supremo, el espacio c0 (Ω, X) formado por las funciones f : Ω → X tales que para cada ε > 0 el conjunto {ω ∈ Ω : || f(ω) || > ε} es finito es supratonelado si y sólo si X es supratonelado.
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.
Recently Cascales, Kąkol and Saxon showed that in a large class of locally convex spaces (so called class G) every Fréchet-Urysohn space is metrizable. Since there exist (under Martin’s axiom) nonmetrizable separable Fréchet-Urysohn spaces C(X) and only metrizable spaces C(X) belong to class G, we study another sufficient conditions for Fréchet-Urysohn locally convex spaces to be metrizable.
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