On Hilbert space operators and operator roots of polynomials
Frank S. Cater · Pacific Journal of Mathematics · 1962
The structure of evp operators* In this section let A be an operator on a vector space V over the field F, and let F λ be the linear manifold consisting of all vectors annihilated by some power of the operator A -λ, for each λ in F.LEMMA 1.Let X and μ be distinct scalars and let z be a vector such that