W*-algebras on Banach spaces
Wavelet transform for functions with values in UMD spaces
We extend the classical theory of the continuous and discrete wavelet transform to functions with values in UMD spaces. As a by-product we obtain equivalent norms on Bochner spaces in terms of g-functions.
Weak compactness and σ-Asplund generated Banach spaces
σ-Asplund generated Banach spaces are used to give new characterizations of subspaces of weakly compactly generated spaces and to prove some results on Radon-Nikodým compacta. We show, typically, that in the framework of weakly Lindelöf determined Banach spaces, subspaces of weakly compactly generated spaces are the same as σ-Asplund generated spaces. For this purpose, we study relationships between quantitative versions of Asplund property, dentability, differentiability, and of weak compactness...
Weak compactness in the dual of a C*-algebra is determined commutatively.
Weak continuity of holomorphic automorphisms in JB-triples.
Weak countable compactness implies quasi-weak drop property
Every weakly countably compact closed convex set in a locally convex space has the quasi-weak drop property.
Weak moduli of convexity.
Let E be a real normed linear space with unit ball B and unit sphere S. The classical modulus of convexity of J. A. Clarkson [2] δE(ε) = inf {1 - 1/2||x + y||: x,y ∈ B, ||x - y|| ≥ ε} (0 ≤ ε ≤ 2)is well known and it is at the origin of a great number of moduli defined by several authors. Among them, D. F. Cudia [3] defined the directional, weak and directional weak modulus of convexity of E, respectively, asδE(ε,g) = inf {1 - 1/2||x + y||: x,y ∈ B, g(x-y) ≥ ε}δE(ε,f) = inf {1 - 1/2 f(x,y): x,y...
Weak-norm sequentially continuous operators
Weak orthogonality and weak property () in some Banach sequence spaces
It is proved that a Köthe sequence space is weakly orthogonal if and only if it is order continuous. Criteria for weak property () in Orlicz sequence spaces in the case of the Luxemburg norm as well as the Orlicz norm are given.
Weak uniform normal structure and iterative fixed points of nonexpansive mappings
This paper is concerned with weak uniform normal structure and iterative fixed points of nonexpansive mappings. Precisely, in Section 1, we show that the geometrical coefficient β(X) for a Banach space X recently introduced by Jimenez-Melado [8] is exactly the weakly convergent sequence coefficient WCS(X) introduced by Bynum [1] in 1980. We then show in Section 2 that all kinds of James' quasi-reflexive spaces have weak uniform normal structure. Finally, in Section 3, we show that in a space X with...
Weak uniform normal structure in direct sum spaces
The weak normal structure coefficient WCS(X) is computed or bounded when X is a finite or infinite direct sum of reflexive Banach spaces with a monotone norm.
Weak uniform rotundity in Orlicz spaces
Weak uniform rotundity of Musielak--Orlicz spaces
We give necessary and sufficient conditions for weak uniform rotundity of Musielak–Orlicz spaces with the Luxemburg norm. The result is a generalization of a theorem by Kami’nska and Kurc.
Weak vs. norm compactness in : the Bocce criterion
Weakly compact sets in Orlicz sequence spaces
We combine the techniques of sequence spaces and general Orlicz functions that are broader than the classical cases of -functions. We give three criteria for the weakly compact sets in general Orlicz sequence spaces. One criterion is related to elements of dual spaces. Under the restriction of , we propose two other modular types that are convenient to use because they get rid of elements of dual spaces. Subsequently, by one of these two modular criteria, we see that a set in Riesz spaces ...
Weakly unconditionally convergent series in M-ideals.
Weakly uniformly rotund Banach spaces
The dual space of a WUR Banach space is weakly K-analytic.
Well embedded Hilbert subspaces in C*-algebras
Weyl numbers versus Z-Weyl numbers
Given an infinite-dimensional Banach space Z (substituting the Hilbert space ℓ₂), the s-number sequence of Z-Weyl numbers is generated by the approximation numbers according to the pattern of the classical Weyl numbers. We compare Weyl numbers with Z-Weyl numbers-a problem originally posed by A. Pietsch. We recover a result of Hinrichs and the first author showing that the Weyl numbers are in a sense minimal. This emphasizes the outstanding role of Weyl numbers within the theory of eigenvalue distribution...
Wheeling around von Neumann-Jordan constant in Banach spaces
In recent times, many constants in Banach spaces have been defined and/or studied. Relations and inequalities among them (sometimes very complicated) have been indicated. But not much effort has been devoted to organize all connections, also because the literature on the subject is growing at an always bigger rate. Here we give some new connections which better the insight on some of them. In particular, we improve a known inequality between the von Neumann-Jordan and James constants.