Inversion von Fredholmfunktionen bei stetiger und holomorpher Abhängigkeit von Parametern.
Invertibility characterization of Wiener-Hopf plus Hankel operators via odd asymmetric factorizations.
Joint essential spectra
Kato decomposition of linear pencils
T. Kato [5] found an important property of semi-Fredholm pencils, now called the Kato decomposition. M. A. Kaashoek [3] introduced operators having the property P(S:k) as a generalization of semi-Fredholm operators. In this work, we study this class of operators. We show that it is characterized by a Kato-type decomposition. Other properties are also proved.
K-Groups of Toeplitz Algebras of Reinhardt Domains.
Lambert multipliers between spaces
In this paper Lambert multipliers acting between spaces are characterized by using some properties of conditional expectation operator. Also, Fredholmness of corresponding bounded operators is investigated.
Layer potentials on boundaries with corners and edges
Locally spectrally bounded linear maps
Let be the algebra of all bounded linear operators on a complex Hilbert space . We characterize locally spectrally bounded linear maps from onto itself. As a consequence, we describe linear maps from onto itself that compress the local spectrum.
Lower s-numbers and their asymptotic behaviour
Lp-essential Spectral Theory of Ordinary Differential Operators With Almost Constant Coefficients
Measures of Non-strict-singularity and Non-strict-cosingularity
Multiple eigenvalue bifurcation for Fredholm operators.
Multiplication operators on Bergman spaces.
New extended Weyl type theorems
Note on operational quantities and Mil'man isometry spectrum.
Let X and Y be infinite dimensional Banach spaces and let L(X,Y) be the class of all (linear continuous) operators acting between X and Y. Mil'man [5] introduced the isometry spectrum I(T) of T ∈ L(X,Y) in the following way:I(T) = {α ≥ 0: ∀ ε > 0, ∃M ∈ S∞(X), ∀x ∈ SM, | ||Tx|| - α | < ε}},where S∞(X) is the set of all infinite dimensional closed subspaces of X and SM := {x ∈ M: ||x|| = 1} is the unit sphere of M ∈ S∞(X). (...)
On a class of Toeplitz + Hankel operators.
On a formula for the jumps in the semi-Fredholm domain.
In this paper we prove some properties of the lower s-numbers and derive asymptotic formulae for the jumps in the semi-Fredholm domain of a bounded linear operator on a Banach space.
On a question of Mbekhta.
The present paper deals with a question of M. Mbekhta concerning partial isometries on Banach spaces.
On Atkinson Operators in Locally Convex Spaces.
On certain quantities in Fredholm operator theory and Mil'man's isometry spectrum