Über das Randspektrum komplexer ordnungsbeschränkter Operatoren in Banachverbänden.
Über das Spektrum positiver Generatoren.
Über die Verallgemeinerung eines Satzes von Kato.
Un majorant du nombre des valeurs propres négatives correspondantes à l’opérateur de Schrödinger généralisé.
On donne une borne supérieur du nombre des valeurs propres négatives de l’opérateur de Schrödinger généralisé, cette borne est donnée en fonction d’un nombre fini de cube dyadiques minimaux.
Unbounded Toeplitz operators in the Bargmann-Segal space
Unimodular Eigenvalues and Invariant Measures for Linear Operators.
Uniqueness in the first maximum problem.
Unitary asymptotes of Hilbert space operators
In this survey article we are going to present the effectiveness of the use of unitary asymptotes in the study of Hilbert space operators.
Unitary dilation for polar decompositions of p-hyponormal operators
In this paper, we introduce the angular cutting and the generalized polar symbols of a p-hyponormal operator T in the case where U of the polar decomposition T = U|T| is not unitary and study spectral properties of it.
Universal Jamison spaces and Jamison sequences for C₀-semigroups
An increasing sequence of positive integers is said to be a Jamison sequence if for every separable complex Banach space X and every T ∈ ℬ(X) which is partially power-bounded with respect to , the set is at most countable. We prove that for every separable infinite-dimensional complex Banach space X which admits an unconditional Schauder decomposition, and for any sequence which is not a Jamison sequence, there exists T ∈ ℬ(X) which is partially power-bounded with respect to and has the...
Upper and Lower Fredholm Spectra II.