Measurable Functional Calculus and Spectral theory

Abstract

In this article, the spectral theory is considered, we study the spectral families and their correspondence to the operators on the reflexive Banach spaces; assume is a well-bounded operator on reflexive Lebesgue spaces then the operator A is a scalar type spectral operator. It is proven that if a weak spectral family is concentrated on [a,b] then there is a linear well-bounded operator on the reflexive Banach space X such that holds for all and .