Let be a bounded countable metric space and a constant, such that , for any pairwise distinct points of . For such metric spaces we prove that they can be isometrically embedded into any Banach space containing an isomorphic copy of .
We introduce the definition of -limited completely continuous operators, . The question of whether a space of operators has the property that every -limited subset is relative compact when the dual of the domain and the codomain have this property is studied using -limited completely continuous evaluation operators.
It is shown that the weak spaces , and are isomorphic as Banach spaces.
We introduce a property for a couple of topologies that allows us to give simple proofs of some classic results about Borel sets in Banach spaces by Edgar, Schachermayer and Talagrand as well as some new results. We characterize the existence of Kadec type renormings in the spirit of the new results for LUR spaces by Moltó, Orihuela and Troyanski.
The Kolmogorov n-diameter of a bounded set B in a non-archimedean normed space, as defined by the first author in a previous paper, is studied in terms of the norms of orthogonal subsets of B with n + 1 points.
We study weakly precompact sets and operators. We show that an operator is weakly precompact if and only if its adjoint is pseudo weakly compact. We study Banach spaces with the --limited and the -(SR) properties and characterize these classes of Banach spaces in terms of --limited and -Right subsets. The --limited property is studied in some spaces of operators.