SOME PROPERTIES OF THE M−ESSENTIAL SPECTRA OF CLOSED LINEAR OPERATOR ON A BANACH SPACE
Aymen Ammar · Functional Analysis, Approximation and Computation · 2015
In this paper, we study a detailed treatment of some subsets of M-essential spectra of closed linear operators subjected to additive perturbations not necessarily belonging to any ideal of the algebra of bounded linear operators and we investigate some properties of the M-essential spectra of 2 × 2 matrix operator acting on a Banach space. This study led us to generalize some well known results for essential spectra of closed linear operator.