All separable Banach space admit for every ε>0 fundamental total and bounded by 1 + ε biorthogonal sequences
Almost ball remotal subspaces in Banach spaces
We investigate almost ball remotal and ball remotal subspaces of Banach spaces. Several subspaces of the classical Banach spaces are identified having these properties. Some stability results for these properties are also proved.
Almost demi Dunford--Pettis operators on Banach lattices
We introduce new concept of almost demi Dunford–Pettis operators. Let be a Banach lattice. An operator from into is said to be almost demi Dunford–Pettis if, for every sequence in such that in and as , we have as . In addition, we study some properties of this class of operators and its relationships with others known operators.
Almost exactness in normed spaces II
In the normed space of bounded operators between a pair of normed spaces, the set of operators which are "bounded below" forms the interior of the set of one-one operators. This note is concerned with the extension of this observation to certain spaces of pairs of operators.
Almost isomeric embeddings of in pre-duals of von Neumann algebras.
Almost sure summability of subsequences in Banach spaces
Almost surjective ε-isometries of Banach spaces
We investigate Hyers-Ulam stability of non-surjective ε-isomeries of Banach spaces. We also pose and discuss an open problem.
Almost Weakly Compact Operators
Dunford-Pettis type properties are studied in individual Banach spaces as well as in spaces of operators. Bibasic sequences are used to characterize Banach spaces which fail to have the Dunford-Pettis property. The question of whether a space of operators has a Dunford-Pettis property when the dual of the domain and the codomain have the respective property is studied. The notion of an almost weakly compact operator plays a consistent and important role in this study.
Alternative axioms for statistical physical theories
AM-Compactness of some classes of operators
We characterize Banach lattices on which each regular order weakly compact (resp. b-weakly compact, almost Dunford-Pettis, Dunford-Pettis) operator is AM-compact.
Amenability for discrete convolution semigroup algebras.
Amenability for dual Banach algebras
We define a Banach algebra 𝔄 to be dual if 𝔄 = (𝔄⁎)* for a closed submodule 𝔄⁎ of 𝔄*. The class of dual Banach algebras includes all W*-algebras, but also all algebras M(G) for locally compact groups G, all algebras ℒ(E) for reflexive Banach spaces E, as well as all biduals of Arens regular Banach algebras. The general impression is that amenable, dual Banach algebras are rather the exception than the rule. We confirm this impression. We first show that under certain conditions an amenable...
An absolute continuity for positive operators on Banach lattices.
An algebraic characterization of complete inner product spaces.
An almost nowhere Fréchet smooth norm on superreflexive spaces
Every separable infinite-dimensional superreflexive Banach space admits an equivalent norm which is Fréchet differentiable only on an Aronszajn null set.
An alternative Dunford-Pettis Property
An alternative to the Dunford-Pettis Property, called the DP1-property, is introduced. Its relationship to the Dunford-Pettis Property and other related properties is examined. It is shown that -direct sums of spaces with DP1 have DP1 if 1 ≤ p < ∞. It is also shown that for preduals of von Neumann algebras, DP1 is strictly weaker than the Dunford-Pettis Property, while for von Neumann algebras, the two properties are equivalent.
An alternative polynomial Daugavet property
We introduce a weaker version of the polynomial Daugavet property: a Banach space X has the alternative polynomial Daugavet property (APDP) if every weakly compact polynomial P: X → X satisfies . We study the stability of the APDP by c₀-, - and ℓ₁-sums of Banach spaces. As a consequence, we obtain examples of Banach spaces with the APDP, namely and C(K,X), where X has the APDP.
An alternative proof of Petty's theorem on equilateral sets
The main goal of this paper is to provide an alternative proof of the following theorem of Petty: in a normed space of dimension at least three, every 3-element equilateral set can be extended to a 4-element equilateral set. Our approach is based on the result of Kramer and Németh about inscribing a simplex into a convex body. To prove the theorem of Petty, we shall also establish that for any three points in a normed plane, forming an equilateral triangle of side p, there exists a fourth point,...
An amalgamation of the Banach spaces associated with James and Schreier, Part I: Banach-space structure
We create a new family of Banach spaces, the James-Schreier spaces, by amalgamating two important classical Banach spaces: James' quasi-reflexive Banach space on the one hand and Schreier's Banach space giving a counterexample to the Banach-Saks property on the other. We then investigate the properties of these James-Schreier spaces, paying particular attention to how key properties of their 'ancestors' (that is, the James space and the Schreier space) are expressed in them. Our main results include...
An amalgamation of the Banach spaces associated with James and Schreier, Part II: Banach-algebra structure
The James-Schreier spaces, defined by amalgamating James' quasi-reflexive Banach spaces and Schreier space, can be equipped with a Banach-algebra structure. We answer some questions relating to their cohomology and ideal structure, and investigate the relations between them. In particular we show that the James-Schreier algebras are weakly amenable but not amenable, and relate these algebras to their multiplier algebras and biduals.