Essential spectra of some matrix operators involving γ-relatively bounded entries and an application
Aref Jeribi, Bilel Krichen, Mohammed Zerai Dhahri · Linear and Multilinear Algebra · 2015
In this paper, we introduce the concept of relative boundedness with respect to an axiomatic measure of noncompactness , as a generalization of the notion of relative boundedness. Then, some spectral properties of a unbounded block operator matrix involving -relatively bounded inputs are given. The obtained results are applied to investigate the essential spectra of a two-dimensional transport operator in with abstract boundary conditions relating the incoming and the outgoing fluxes.