Partial *-algebras of closed operators and their commutants. I. General structure
Partial *-algebras of closed operators and their commutants. II. Commutants and bicommutants
Periodic Schrödinger Operators with (Non-Periodic) Magnetic and Electric Potentials.
Perturbation of a Fredholm complex by inessential operators.
Perturbation of the spectrum οf an essentially selfadjoint operator
The aim of this paper is to find estimates of the Hausdorff distance between the spectra of two nonselfadjoint operators. The operators considered are assumed to have their imaginary parts in some normed ideal of compact operators. In the case of the classical Schatten ideals the estimates are given explicitly.
Perturbation of Toeplitz operators and reflexivity
It was shown that the space of Toeplitz operators perturbated by finite rank operators is 2-hyperreflexive.
Polynomial identification in uniform and operator algebras.
Pontryagin duality for convergence groups of unimodular continuous functions
Positive linear maps of matrix algebras
A characterization of the structure of positive maps is presented. This sheds some more light on the old open problem studied both in Quantum Information and Operator Algebras. Our arguments are based on the concept of exposed points, links between tensor products and mapping spaces and convex analysis.
Powers and Logarithms
There are applied power mappings in algebras with logarithms induced by a given linear operator D in order to study particular properties of powers of logarithms. Main results of this paper will be concerned with the case when an algebra under consideration is commutative and has a unit and the operator D satisfies the Leibniz condition, i.e. D(xy) = xDy + yDx for x, y ∈ dom D. Note that in the Number Theory there are well-known several formulae expressed by means of some combinations of powers...
p-representable operators in Banach spaces.
Projections onto the spaces of Toeplitz operators
Projections onto the spaces of all Toeplitz operators on the N-torus and the unit sphere are constructed. The constructions are also extended to generalized Toeplitz operators and applied to show hyperreflexivity results.
Propriétés géométriques des sous-espaces invariants par translation de et
Propriétés spectrales des restrictions d’opérateurs de la classe