Some results on semi-Fredholm perturbations of multivalued linear operators
Aymen Ammar · Linear and Multilinear Algebra · 2017
The upper and lower semi-Fredholm perturbations of multivalued linear operators were discussed in a previous paper by Álvarez et al. (J. Math Methods Appl Sci. 2014;37(5):620–644). The purpose of the present study is to investigate the and -Atkinson perturbation of linear relations. After that, we use the reached findings to establish a survey of results concerning various essential spectra of linear relations. We finish this paper by establishing some results of the essential spectra of a transport equations with abstract boundary conditions in -spaces.