Liu, X.J.Qin, X.L.Benítez López, Julio2016-05-232016-05-232015-121005-1031https://riunet.upv.es/handle/10251/64564In this paper, we investigate additive results of the Drazin inverse of elements in a ring R. Under the condition ab = ba, we show that a + b is Drazin invertible if and only if aa^D(a+b) is Drazin invertible, where the superscript D means the Drazin inverse. Furthermore we find an expression of (a + b)^D. As an application we give some new representations for the Drazin inverse of a 2 × 2 block matrix.Reserva de todos los derechosDrazin inverseRingBlock matrixMATEMATICA APLICADAArtículo10.1007/s11766-015-3333-4Abierto