SOME RESULTS OF FREDHOLM PERTURBATIONS OF MULTIVALUED LINEAR OPERATOR IN NORMED SPACES

Abstract

In the present paper, we establish rst the relation between the perturbation of upper Fredholm and strictly singular, and then the relation between lower semi-Fredholm and strictly cosingular linear relations. Most importantly in Theorem 2.1, we show that P(F−(X,Y)) coincides with SC(X,Y). We bring to light, the relationship between the essential spectra of a multivalued linear operator and its selection.