On a recent result concerning the Drazin inverse of matrices

Abstract

In this paper, we investigate the recent paper of Shakoor et al. [A. Shakoor, I.
Ali, S. Wali, A. Rehman, Some formulas on the Drazin inverse for the sum of two matrices and block matrices, Bull. Iran. Math. Soc. (2021) https://doi.org/10.1007/s41980-020-00521-3]. Here we prove that the main, additive result from the mentioned paper is actually a corollary of one known result. Furthermore, we give new representations for the Drazin inverse of the anti–triangular block matrix, which generalizes some representations from current literature on the topic.