On the second quantisation of Hilbert-Schmidt processes
On the singular numbers for some integral operators.
Two-sided estimates of Schatten-von Neumann norms for weighted Volterra integral operators are established. Analogous problems for some potential-type operators defined on Rn are solved.
On the solvability of the Lyapunov equation for nonselfadjoint differential operators of order 2m with nonlocal boundary conditions
This paper is devoted to the solvability of the Lyapunov equation A*U + UA = I, where A is a given nonselfadjoint differential operator of order 2m with nonlocal boundary conditions, A* is its adjoint, I is the identity operator and U is the selfadjoint operator to be found. We assume that the spectra of A* and -A are disjoint. Under this restriction we prove the existence and uniqueness of the solution of the Lyapunov equation in the class of bounded operators.
On the space of φ-nuclear operators on l2.
We consider the generalization Sphi of the Schatten classes Sp obtained in correspondence with opportune continuous, strictly increasing, sub-additive functions phi such that phi(0) = 0 and phi(1) = 1. The purpose of this note is to study the spaces Sphi of the phi-nuclear operators and to compare their properties to those of the by now well-known space S1 of nuclear operators.
On the surjective (injective) envelope of strictly (co-) singular operators
On the tensor product weakly compact operators.
On the Tensor Stability of s-Number Ideals.
On the topology of compactoid convergence in non-Archimedean spaces
On the trace of some operators
On triangularization of algebras of operators.
On truncations of Hankel and Toeplitz operators.
We study the boundedness properties of truncation operators acting on bounded Hankel (or Toeplitz) infinite matrices. A relation with the Lacey-Thiele theorem on the bilinear Hilbert transform is established. We also study the behaviour of the truncation operators when restricted to Hankel matrices in the Schatten classes.
On weak (r,2)-summing operators and weak Hilbert spaces
On -nuclearity
One criterion for nuclearity of linear operators.
Operadores antisimétricos y de rango finito en espacios de Hilbert.
Opérateurs se factorisant par un espace , d’après S. Kwapien (suite et fin)
Opérateurs se factorisant par un espace , d’après S. Kwapien
Opérateurs sommants et factorisations. A travers les espaces
Opérateurs sommants sur un cone normal d un espace de Banach.
The aim of this paper is to develop a theory of p-summing operators (between Banach spaces) in presence of an order structure given by a convex normal cone.
Operational quantities derived from the norm and generalized Fredholm theory
We introduce and study some operational quantities associated to a space ideal . These quantities are used to define generalized semi-Fredholm operators associated to , and the corresponding perturbation classes which extend the strictly singular and strictly cosingular operators, and we study the generalized Fredholm theory obtained in this way. Finally we present some examples and show that the classes of generalized semi-Fredholm operators are non-trivial for several classical space ideals.