New description of the structured essential pseudospectra

In this paper, we outline a new approach to the study of structured Schechter and structured Browder essential pseudospectra of closed densely defined linear operators on infinite dimensional Banach spaces via the concept of the measure of noncompactness and the measure of non strict-singularity. Furthermore, we investigate the structured Wolf, structured Schechter and structured Browder essential pseudospectra of the sum of two bounded operators.