Starke Konvergenz im verallgemeinerten Sinne und Spektra.
Stetigkeit des Spektrums einer Klasse nichtlinearer Operatoren II
Stetigkeit des Spektrums im Kleinen Einer Klasse Nichtlineare Operatoren I
Strong resonant tunneling, level repulsion and spectral type for one-dimensional adiabatic quasi-periodic Schrödinger operators
Structures of left n-invertible operators and their applications
We study left n-invertible operators introduced in two recent papers. We show how to construct a left n-inverse as a sum of a left inverse and a nilpotent operator. We provide refinements for results on products and tensor products of left n-invertible operators by Duggal and Müller (2013). Our study leads to improvements and different and often more direct proofs of results of Duggal and Müller (2013) and Sid Ahmed (2012). We make a conjecture about tensor products of left n-invertible operators...
Subspace gaps and Weyl's theorem for an elementary operator.
Sums of idempotents and a lemma of N. J. Kalton
A lemma of Gelfand-Hille type is proved. It is used to give an improved version of a result of Kalton on sums of idempotents.
Sur le spectre d'un shift à poids opérateurs.
Sur les bornes d'erreur a posteriori pour les éléments propres d'opérateurs linéaires.
Sur les transformations additives qui conservent le spectre de surjection.
Survey of some results in spectral theory obtained in Prague
Taylor Spectrum and Characteristic Functions of Commuting 2-Contractions
2000 Mathematics Subject Classification: 47A10, 47A13.In this paper, we give a description of Taylor spectrum of commuting 2-contractions in terms of characteritic functions of such contractions. The case of a single contraction obtained by B. Sz. Nagy and C. Foias is generalied in this work.
Tensor product of left n-invertible operators
A Banach space operator T ∈ has a left m-inverse (resp., an essential left m-inverse) for some integer m ≥ 1 if there exists an operator S ∈ (resp., an operator S ∈ and a compact operator K ∈ ) such that (resp., ). If is left -invertible (resp., essentially left -invertible), then the tensor product T₁ ⊗ T₂ is left (m₁ + m₂-1)-invertible (resp., essentially left (m₁ + m₂-1)-invertible). Furthermore, if T₁ is strictly left m-invertible (resp., strictly essentially left m-invertible), then...
Tensor products and elementary operators.
Tensor products and Taylor's joint spectrum
Tensor products of linear operators in locally convex spaces
The boundary of Taylor's joint spectrum for two commuting Banach space operators
The boundary spectrum of linear operators in finite-dimensional spaces
The Cesàro and related operators, a survey
We provide a survey of properties of the Cesàro operator on Hardy and weighted Bergman spaces, along with its connections to semigroups of weighted composition operators. We also describe recent developments regarding Cesàro-like operators and indicate some open questions and directions of future research.
The comparison of spectrum of normalizable matrices