Generalized lower characteristic involving measures of non-strict singularity

Abstract

This work establishes a connection between the class of generalized lower characteristic operators and [⋅]a{\left[\cdot ]}_{a} acting on a Banach space involving measures of non-strict singularity. This study presents findings on the Jeribi essential spectra of the sum of two bounded linear operators and the Jeribi essential spectra of each operator. The results are based on certain requirements related to the measure of non-strict singularity of Fredholm inverses on a Banach space X. A particular application is provided.

Keywords

• fredholm theory
• generalized lower characteristic operators
• primary 47a10
• secondary 47a55
• 47a53