Several books have been devoted to the spectral theory and its applications. However, this
volume is very special as compared with the previous ones. For example, the perturbation …

Linear Operators and Their Essential Pseudospectra provides a comprehensive study of
spectral theory of linear operators defined on Banach spaces. The central items of interest in …

This book gives a fairly comprehensive review of important aspects of the spectral theory,
covering, in particular, the completeness of generalized eigenvectors, the Riesz bases, the …

In this article, we introduce the concept of demicompactness with respect to a closed
densely defined linear operator, as a generalization of the class of demicompact operator …

The concept of multivalued linear operators—or linear relations—is the one of the most
exciting and influential fields of research in modern mathematics. Applications of this theory …

In this paper, we provide some results in concern with the so called g-Riesz operators acting
on a non-reflexive Banach space X having some properties. Therefore, we investigate some …

We characterize some S-essential spectra of a closed linear relation in terms of certain
linear relations of semi-Fredholm type. 1. Introduction. Let S and T be bounded operators …

Stability of the S-left and S-right essential spectra of a linear operator Page 1 Acta Mathematica
Scientia 2014,34B(6):1922–1934 http://actams.wipm.ac.cn STABILITY OF THE S-LEFT AND …

The concept of the line graph of a given graph is so natural that it has been independently
discovered by many authors. Of course, each author gave it a different name: It was called …

In this paper, we establish some properties concerning the condition pseudospectrum of the
linear operator pencils λ S− T when, S is not necessarily invertible. Also, we give some …