Almost constrained subspaces of Banach spaces

Central and Almost Constrained Subspaces of Banach Spaces

In this paper we continue the study of central subspaces initiated in [2] and its infinite version called almost constrained subspaces. We are interested in studying situations where these intersection properties of balls lead to the existence of a linear projection of norm one. We show that every finite dimensional subspace is a central subspace only in Hilbert spaces. By considering direct su...

On quasi-complemented subspaces of banach spaces.

BANACH SPACES OF POLYNOMIALS AS “LARGE” SUBSPACES OF l∞-SPACES

In this note we study Banach spaces of traces of real polynomials on R to compact subsets equipped with supremum norms from the point of view of Geometric Functional Analysis.

Strongly Proximinal Subspaces in Banach Spaces

We give descriptions of SSDand QP -points in C(K)-spaces and use this to characterize strongly proximinal subspaces of finite codimension in L1(μ). We provide some natural class of examples of strongly proximinal subspaces which are not necessarily finite codimensional. We also study transitivity of strong proximinal subspaces of finite codimension.

Characterizations of almost transitive superreflexive Banach spaces

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 ...