Modèles d'opérateurs linéaires et translations unilatérales simples
Moyennes de fonctions et opérateurs multiplicativement liés
On Connection between Characterestic Functions and the Caratheodori Class Functions
2000 Mathematics Subject Classification: 47A65, 45S78.Connection of characteristic functions S(z) of nonunitary operator T with the functions of Caratheodori class is established. It was demonstrated that the representing measures from integral representation of the function of Caratheodori's class are defined by restrictions of spectral measures of unitary dilation, of a restricted operator T on the corresponding defect subspaces.
On continuity of linear transformations commuting with generalized scalar operators in Banach space
On estimates for spectral projections of perturbed selfadjoint operators.
On linear operators having supercyclic vectors
We show that for a real separable Banach space X there are operators in B(X) having supercyclic vectors if and only if dim X ≤ 2 or dim X = ∞.
On Multiplicative Lebesgue Integration and Families of Evolution Operators.
On operators T such that f(T) is hypercyclic.
On operators with unitary ϱ-dilations
We show a polynomially boundend operator T is similar to a unitary operator if there is a singular unitary operator W and an injection X such that XT = WX. If, in addition, T is of class , then T itself is unitary.
On strictly cyclic operator algebras.
In the present paper we prove that a strictly cyclic, not invertible unicellular operator is quasinilpotent.
On the canonical development of Parseval formulas for singular differential operators
Per funzioni opportune si ottiene una formula di Parseval per operatori differenziali singolari di tipo dell'operatore radiale di Laplace-Beltrami. è una funzione spettrale generalizzata di tipo Marčenko e può essere rappresentata per mezzo di un certo nucleo della trasmutazione.
On the Fine Structure of Spectra.
On the norm-closure of the class of hypercyclic operators
Let T be a bounded linear operator acting on a complex, separable, infinite-dimensional Hilbert space and let f: D → ℂ be an analytic function defined on an open set D ⊆ ℂ which contains the spectrum of T. If T is the limit of hypercyclic operators and if f is nonconstant on every connected component of D, then f(T) is the limit of hypercyclic operators if and only if is connected, where denotes the Weyl spectrum of T.
On the orbits of an operator with spectral radius one
On the shift operators.
On the structure of commuting isometries
On weak (r,2)-summing operators and weak Hilbert spaces
Operators on a Hilbert space similar to a part of the backward shift of multiplicity one
Let A: X → X be a bounded operator on a separable complex Hilbert space X with an inner product . For b, c ∈ X, a weak resolvent of A is the complex function of the form . We will discuss an equivalent condition, in terms of weak resolvents, for A to be similar to a restriction of the backward shift of multiplicity 1.
Order bounded orthosymmetric bilinear operator
It is proved by an order theoretical and purely algebraic method that any order bounded orthosymmetric bilinear operator where and are Archimedean vector lattices is symmetric. This leads to a new and short proof of the commutativity of Archimedean almost -algebras.
Polynomial identification in uniform and operator algebras.