On Determining the Eigenprojection and Components of a Matrix

Matrix theory and its applications make wide use of the eigenprojections of square matrices. The present paper demonstrates that the eigenprojection of a matrix $A$ can be calculated with the use of any annihilating polynomial of A^u, where u >= ind A. This enables one to find the components and the minimal polynomial of A, as well as the Drazin inverse A^D.