  We establish some relationships between an m-accretive operator and its
Moore-Penorse inverse. We derive some perturbation result of the Moore-Penorse
inverse of a maximal accretive operator. As an application we give a
factorization theorem for a quadratic pencil of accretive operators. Also, we
study a result of existence, uniqueness, and maximal regularity of the strict
solution for complete abstract second order differential equation. Illustrative
examples are also given.
