Approximation des bornés d'un espace de Banach par des compacts et applications
Approximation numbers of composition operators on H p
give estimates for the approximation numbers of composition operators on the Hp spaces, 1 ≤ p < ∞
Approximation of eigenvalues for unbounded Jacobi matrices using finite submatrices
We consider an infinite Jacobi matrix with off-diagonal entries dominated by the diagonal entries going to infinity. The corresponding self-adjoint operator J has discrete spectrum and our purpose is to present results on the approximation of eigenvalues of J by eigenvalues of its finite submatrices.
Approximation of generalized homomorphisms in quasi-Banach algebras.
Approximation of generalized left derivations.
Approximation of positive operators and continuity of the spectral radius. II.
Approximation of translation invariant operators
Approximation par des opérateurs compacts ou faiblement compacts à valeurs dans
Soient et . Il existe une application (non linéaire) normiquement continue de l’espace des opérateurs bornés de dans sur l’espace des opérateurs compacts (resp. faiblement compacts) de dans telle que coïncide avec la distance de au sous-espace formé des opérateurs compacts (resp. faiblement compacts). Pour un opérateur donné de dans on étudie les propriétés de l’ensemble (resp. ) des opérateurs compacts (resp. faiblement compacts) tel que pour tout de (resp. ) la quantité...
Approximation properties determined by operator ideals and approximability of homogeneous polynomials and holomorphic functions
Given an operator ideal ℐ, a Banach space E has the ℐ-approximation property if the identity operator on E can be uniformly approximated on compact subsets of E by operators belonging to ℐ. In this paper the ℐ-approximation property is studied in projective tensor products, spaces of linear functionals, spaces of linear operators/homogeneous polynomials, spaces of holomorphic functions and their preduals.
Approximation spectral d'un opérateur borné et normal à l'aide de ses fonctions de la densité spectrale
Approximation the Shift with Toeplitz Operators.
Approximation with Restricted Spectra.
Approximations of contraction operators on - I
Approximations of Positive Contractions on Loo. II.
Approximationszahlen, p-nukleare Operatoren und Hilbertraumcharakterisierungen.
Area differences under analytic maps and operators
Motivated by the relationship between the area of the image of the unit disk under a holomorphic mapping and that of , we study various norms for , where is the Toeplitz operator with symbol . In Theorem , given polynomials and we find a symbol such that . We extend some of our results to the polydisc.
Around the Furuta inequality – the operator inequalities .
Around the Kato generation theorem for semigroups
We show that the result of Kato on the existence of a semigroup solving the Kolmogorov system of equations in l₁ can be generalized to a larger class of the so-called Kantorovich-Banach spaces. We also present a number of related generation results that can be proved using positivity methods, as well as some examples.
Ascent and descent of weighted composition operators on L^p-spaces
Aspects of the theory of derivations
We survey some old and new results in the theory of derivations on Banach algebras. Although our overview is broad ranging, our principal interest is in recent results concerning conditions on a derivation implying that its range is contained in the radical of the algebra.