2 citations · 2 across the 4 of their papers we have counts for
5 papers
Spectral theory for structured perturbations of linear operators
Martin Adler, Klaus-Jochen Engel
We characterize the spectrum (and its parts) of operators which can be represented as G=A+BC for a simpler operator A and a structured perturbation BC. The interest in this kind of…
A semigroup approach to the numerical range of operators on Banach spaces
Martin Adler, Waed Dada, Agnes Radl
We introduce the numerical spectrum of an (unbounded) linear operator on a Banach space and study its properties. Our definition is closely relat…
Asymptotic properties of -semigroups under perturbations
Martin Adler
For a given -semigroup we consider Staffans-Weiss perturbations of its generator as studied in [1] and investigate the robustness of asymptotic prop…
Perturbation of Analytic Semigroups and Applications to Partial Differential Equations
Martin Adler, Miriam Bombieri, Klaus-Jochen Engel
In a recent paper we presented a general perturbation result for generators of -semigroups. The aim of the present paper is to replace, in case the unperturbed semigroup is an…
On Perturbations of Generators of -Semigroups
M. Adler, M. Bombieri, K. -J. Engel
We present a perturbation result for generators of -semigroups which can be considered as an operator theoretic version of the Weiss-Staffans perturbation theorem for abstract…