On weakly compact operators from some uniform algebras
On Weakly Compact Operators on C*-Algebras.
On weighted composition operators acting between weighted Bergman spaces of infinite order and weighted Bloch type spaces
Let ϕ: → and ψ: → ℂ be analytic maps. They induce a weighted composition operator acting between weighted Bergman spaces of infinite order and weighted Bloch type spaces. Under some assumptions on the weights we give a characterization for such an operator to be bounded in terms of the weights involved as well as the functions ψ and ϕ
On Well-Located Subspaces of Distribution-Spaces.
On well-posedness of the nonlocal boundary value problem for parabolic difference equations.
On w-hyponormal operators
We study some properties of w-hyponormal operators. In particular we show that some w-hyponormal operators are subscalar. Also we state some theorems on invariant subspaces of w-hyponormal operators.
On Woronowicz's approach to the Tomita-Takesaki theory
The Tomita-Takesaki Theory is very complex and can be contemplated from different points of view. In the decade 1970-1980 several approaches to it appeared, each one seeking to attain more transparency. One of them was the paper of S. L. Woronowicz "Operator systems and their application to the Tomita-Takesaki theory" that appeared in 1979. Woronowicz's approach allows a particularly precise insight into the nature of the Tomita-Takesaki Theory and in this paper we present a brief, but fairly detailed...
On -valued sequence spaces.
On -nuclearity
On λ-commuting operators
For a scalar λ, two operators T and S are said to λ-commute if TS = λST. In this note we explore the pervasiveness of the operators that λ-commute with a compact operator by characterizing the closure and the interior of the set of operators with this property.
Once more about the monotonicity of the Temple quotients
A new proof of the monotonicity of the Temple quotients for the computation of the dominant eigenvalue of a bounded linear normal operator in a Hilbert space is given. Another goal of the paper is a precise analysis of the length of the interval for admissible shifts for the Temple quotients.
Once more on positive commutators
Let A and B be bounded operators on a Banach lattice E such that the commutator C = AB - BA and the product BA are positive operators. If the product AB is a power-compact operator, then C is a quasi-nilpotent operator having a triangularizing chain of closed ideals of E. This answers an open question posed by Bračič et al. [Positivity 14 (2010)], where the study of positive commutators of positive operators was initiated.
One criterion for nuclearity of linear operators.
One-dimensional graph perturbations of selfadjoint relations.
Open partial isometries and positivity in operator spaces
We first study positivity in C*-modules using tripotents ( = partial isometries) which are what we call open. This is then used to study ordered operator spaces via an "ordered noncommutative Shilov boundary" which we introduce. This boundary satisfies the usual universal diagram/property of the noncommutative Shilov boundary, but with all the arrows completely positive. Because of their independent interest, we also systematically study open tripotents and their properties.
Opening gaps in the spectrum of strictly ergodic Schrödinger operators
We consider Schrödinger operators with dynamically defined potentials arising from continuous sampling along orbits of strictly ergodic transformations. The Gap Labeling Theorem states that the possible gaps in the spectrum can be canonically labelled by an at most countable set defined purely in terms of the dynamics. Which labels actually appear depends on the choice of the sampling function; the missing labels are said to correspond to collapsed gaps. Here we show that for any collapsed gap,...
Operadores antisimétricos y de rango finito en espacios de Hilbert.
Operadores débilmente compactos e incondicionalmente convergentes en espacios de funciones continuas con valores vectoriales.
Operadores débilmente compactos en espacios de funciones continuas con valores vectoriales, y la propiedad de Radon-Nykodim.
Operadores desplazamiento condicionalmente estrictamente cíclicos.