27 research outputs found
Reflexive Cones
Reflexive cones in Banach spaces are cones with weakly compact intersection
with the unit ball. In this paper we study the structure of this class of
cones. We investigate the relations between the notion of reflexive cones and
the properties of their bases. This allows us to prove a characterization of
reflexive cones in term of the absence of a subcone isomorphic to the positive
cone of \ell_{1}. Moreover, the properties of some specific classes of
reflexive cones are investigated. Namely, we consider the reflexive cones such
that the intersection with the unit ball is norm compact, those generated by a
Schauder basis and the reflexive cones regarded as ordering cones in a Banach
spaces. Finally, it is worth to point out that a characterization of reflexive
spaces and also of the Schur spaces by the properties of reflexive cones is
given.Comment: 23 page
CONES LOCALLY ISOMORPHIC TO THE POSITIVE CONE OF L-1(GAMMA)
AbstractWe give necessary and sufficient conditions in order for an infinite-dimensional, closed cone P of a Banach space X to be locally isomorphic to the positive cone l+1(Γ) of l1(Γ)
Embeddability of L1 (μ) in dual spaces, geometry of cones and a characterization of c0
AbstractIn this article we suppose that (Ω,Σ,μ) is a measure space and T an one-to-one, linear, continuous operator of L1(μ) into the dual E′ of a Banach space E. For any measurable set A consider the image T(L+1(μA)) of the positive cone of the space L1(μA) in E′, where μA is the restriction of the measure μ on A. We provide geometrical conditions on the cones T(L+1(μA)) which yield that the measure μ is atomic, i.e., that L1(μ) is lattice isometric to ℓ1(A), where A denotes the set of atoms of μ. This result yields also a new characterization of c0(Γ)