Extrapolation functors on a family of scales generated by the real interpolation method.
Extrapolatory description for the Lorentz and Marcinkiewicz spaces “close" to .
Extremal properties of the set of vector-valued Banach limits
In this manuscript we find another class of real Banach spaces which admit vector-valued Banach limits different from the classes found in [6, 7]. We also characterize the separating subsets of ℓ∞(X). For this we first need to study when the space of almost convergent sequences is closed in the space of bounded sequences, which turns out to happen only when the underlying space is complete. Finally, a study on the extremal structure of the set of vector-valued Banach limits is conducted when the...
Extremal sections of complex -balls, 0 < p ≤ 2
We study the extremal volume of central hyperplane sections of complex n-dimensional -balls with 0 < p ≤ 2. We show that the minimum corresponds to hyperplanes orthogonal to vectors ξ = (ξ¹,...,ξⁿ) ∈ ℂⁿ with |ξ¹| = ... = |ξⁿ|, and the maximum corresponds to hyperplanes orthogonal to vectors with only one non-zero coordinate.
Extremal Structure of Convex Sets in Spaces Not Containing co.
Extreme cases of weak type interpolation.
We consider quasilinear operators T of joint weak type (a, b; p, q) (in the sense of [2]) and study their properties on spaces Lφ,E with the norm||φ(t) f*(t)||Ê, where Ê is arbitrary rearrangement-invariant space with respect to the measure dt/t. A space Lφ,E is said to be "close" to one of the endpoints of interpolation if the corresponding Boyd index of this space is equal to 1/a or to 1/p. For all possible kinds of such "closeness", we give sharp estimates for the function ψ(t) so as to obtain...
Extreme compact operators from Orlicz spaces to
Let be the subspace of finite elements of an Orlicz space endowed with the Luxemburg norm. The main theorem says that a compact linear operator is extreme if and only if on a dense subset of , where is a compact Hausdorff topological space and . This is done via the description of the extreme points of the space of continuous functions , being an Orlicz space equipped with the Orlicz norm (conjugate to the Luxemburg one). There is also given a theorem on closedness of the set of extreme...
Extreme contractions on certain function spaces
Extreme contractions on C(X) and
Extreme norms on
Extreme operators on AL-spaces
Extreme points and descriptive sets
A class of closed, bounded, convex sets in the Banach space is shown to be a complete PCA set.
Extreme points and rotundity in Musielak-Orlicz-Bochner function spaces endowed with Orlicz norm.
Extreme points and rotundity of Orlicz-Sobolev spaces.
Extreme points in tensor products and a theorem of de Leeuw
Extreme points of the Besicovitch--Orlicz space of almost periodic functions equipped with the Luxemburg norm
We investigate which points in the unit sphere of the Besicovitch--Orlicz space of almost periodic functions, equipped with the Luxemburg norm, are extreme points. Sufficient conditions for the strict convexity of this space are also given.
Extreme points of the complex binary trilinear ball
We characterize all the extreme points of the unit ball in the space of trilinear forms on the Hilbert space . This answers a question posed by R. Grząślewicz and K. John [7], who solved the corresponding problem for the real Hilbert space . As an application we determine the best constant in the inequality between the Hilbert-Schmidt norm and the norm of trilinear forms.
Extreme points of the positive part of the unit ball and strictly monotone norm.
Extreme symmetric norms on
Extremely non-complex Banach spaces
A Banach space X is said to be an extremely non-complex space if the norm equality ∥Id +T 2∥ = 1+∥T 2∥ holds for every bounded linear operator T on X. We show that every extremely non-complex Banach space has positive numerical index, it does not have an unconditional basis and that the infimum of diameters of the slices of its unit ball is positive.