Some Results for the Drazin Inverses of the Sum of Two Matrices and Some Block Matrices

摘要

We give a formula of(P+Q)Dunder the conditionsP2Q+QPQ=0,P3Q=0, andPQPQ=0. Then, we apply it to give some expressions for the Drazin inverse of block matrixM=(ABCD)(AandDare square matrices) under some conditions, generalizing some recent results in the literature. Finally, numerical examples are given to illustrate our results.