The main focus of this book is on bounded linear operators on complex infinitedimensional
Banach spaces and their spectral properties. In recent years spectral theory, which has …

Abstract Let H _ 1 and H _ 2 be separable Hilbert spaces, and let A ∈ B (H _ 1),\, B ∈ B (H _
2) and C ∈ B (H _ 2,\, H _ 1) be given operators. A necessary and sufficient condition is …

We introduce a new class which generalizes the class of B-Weyl operators. We say that is
pseudo B-Weyl if, where is a Weyl operator and is a quasi-nilpotent operator. We show that …

This paper is concerned with general n× n upper-triangular operator matrices with given
diagonal entries. The characterizations of perturbations of their left (resp. right) Weyl …

Completion problems for operator matrices are concerned with the question of whether a
partially specified operator matrix can be completed to form an operator of a desired type …

This paper is concerned with general n * nn× n upper-triangular operator matrices with given
diagonal entries. The characterizations of perturbations of their left (right) essential spectrum …

A Banach space operator T∈ B (χ) is polaroid if points λ∈ iso σ (T) are poles of the
resolvent of T. Let\sigma_a (T),\sigma_w (T), aw (T), SF_+(T)\, and\, SF_-(T) denote …

The semi-Fredholmness of 22 operator matrices Page 1 J. Math. Anal. Appl. 352 (2009) 733–738
Contents lists available at ScienceDirect Journal of Mathematical Analysis and Applications …

Weyl type theorems have been proved for a considerably large number of classes of
operators. In this paper, by introducing the class of quasi totally hereditarily normaloid …

Let H and K be infinite-dimensional separable Hilbert spaces, and denote by MC:= AC 0 B
the upper triangular linear relation matrix with unknown C in H⊕ K. For given relations A …