On the existence of weak solutions for some quasilinear elliptic variational boundary value problems at resonance
On the extension of holomorphic functions on a locally convex space
On the Hardy-type integral operators in Banach function spaces.
Characterization of the mapping properties such as boundedness, compactness, measure of non-compactness and estimates of the approximation numbers of Hardy-type integral operators in Banach function spaces are given.
On the Metric Geometry of Ideals of Operators on Hubert Space.
On the positive absolutely summing operators on the space Lp(μ,X).
On the Range and the Kernel of Derivations
2000 Mathematics Subject Classification: Primary 47B47, 47B10; Secondary 47A30.Let H be a separable infinite dimensional complex Hilbert space and let L(H) denote the algebra of all bounded linear operators on H into itself. Given A ∈ L(H), the derivation δA : L(H)→ L(H) is defined by δA(X) = AX-XA. In this paper we prove that if A is an n-multicyclic hyponormal operator and T is hyponormal such that AT = TA, then || δA(X)+T|| ≥ ||T|| for all X ∈ L(H). We establish the same inequality if A is...
On the range and the kernel of the elementary operators .
On the range-kernel orthogonality of elementary operators
Let denote the algebra of operators on a complex infinite dimensional Hilbert space . For , the generalized derivation and the elementary operator are defined by and for all . In this paper, we exhibit pairs of operators such that the range-kernel orthogonality of holds for the usual operator norm. We generalize some recent results. We also establish some theorems on the orthogonality of the range and the kernel of with respect to the wider class of unitarily invariant norms on...
On the Relationship Between yp-Radonifying Operators and Other Operator Ideals in Banach Spaces of Stable Type p.
On the Relative Completeness of the Generalized Eigenvectors of Elliptic Eigenvalue Problems with Indefinite Weight Functions.
On the r-Nuclearity of Gaussian Covariances and the Composition of Nuclear Operators.
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