Pertubation of Operators and Applications to Frame Theory.
Perturbation Classes of Semi-Fredholm Operators.
Perturbation de générateurs infinitésimaux du type «changement de temps»
On obtient un théorème général concernant la perturbation multiplicative par un opérateur (linéaire borné, mais pas forcément d’inverse borné), du générateur d’un semi-groupe fortement continu sur un espace de Banach. On en déduit un résultat intimement lié au changement de temps dans les processus de Markov, qui étend un théorème de Dorroh (et résout par l’affirmative la seule situation qui restait en doute dans le contexte du théorème de Dorroh cité). Comme exemple d’autres possibilités d’application,...
Perturbation des résolvantes et des semi-groupes par une mesure de Radon positive.
Perturbation of analytic operators and temporal regularity of discrete heat kernels
In analogy to the analyticity condition , t > 0, for a continuous time semigroup , a bounded operator T is called analytic if the discrete time semigroup satisfies , n ∈ ℕ. We generalize O. Nevanlinna’s characterization of powerbounded and analytic operators T to the following perturbation result: if S is a perturbation of T such that is small enough for some , then the type of the semigroup also controls the analyticity of S in the sense that , n ∈ ℕ. As an application we generalize...
Perturbation of Closed Operators and Their Adjoints.
Perturbation of Maps in Locally Convex Spaces.
Perturbation of maximal accretive operators with right angle
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.
Perturbation results on semi-Fredholm operators and applications.
Perturbation theorems for local integrated semigroups
We apply the contraction mapping theorem to establish some bounded and unbounded perturbation theorems concerning nondegenerate local α-times integrated semigroups. Some unbounded perturbation results of Wang et al. [Studia Math. 170 (2005)] are also generalized. We also establish some growth properties of perturbations of local α-times integrated semigroups.
Perturbation theorems for maximal -regularity
Perturbation theorems of Miyadera type for locally Lipschitz continuous integrated semigroups
A class of perturbing operators for locally Lipschitz continuous integrated semigroups is introduced according to the idea of Miyadera. The paper gives perturbation theorems of Miyadera type for such integrated semigroups.
Perturbation theory and strictly singular operators in locally convex spaces
Perturbation Theory for Dual Semigroups. I. The Sun-Reflexive Case.
Perturbation theory for Schrödinger operators with complex potentials
Perturbation theory relative to a Banach algebra of operators
Let ℬ be a Banach algebra of bounded linear operators on a Banach space X. Let S be a closed linear operator in X, and let R be a linear operator in X. In this paper the spectral and Fredholm theory relative to ℬ of the perturbed operator S + R is developed. In particular, the situation where R is S-inessential relative to ℬ is studied. Several examples are given to illustrate the usefulness of these concepts.
Perturbations by Quadratic Forms and Invariance of Essential Spectra.
Perturbations of bi-continuous semigroups
The notion of bi-continuous semigroups has recently been introduced to handle semigroups on Banach spaces that are only strongly continuous for a topology coarser than the norm-topology. In this paper, as a continuation of the systematic treatment of such semigroups started in [20-22], we provide a bounded perturbation theorem, which turns out to be quite general in view of various examples.