Dual core-nilpotent decomposition and dual binary relation

In this paper, we present the definitions of appreciable index and dual index of a dual real square matrix. Then, we introduce the unique dual core-nilpotent (D-C-N) decomposition that exists universally for all dual real square matrices. By applying the decomposition, we get a characterization of the dual Drazin generalized inverse (D-Drazin), introduce D-Drazin, D-C-N, C-sharp C-N (C-C-N) and G-sharp C-N (G-C-N) binary relations of dual real matrices, and discuss relevant properties of these binary relations. We prove that D-Drazin binary relation is a pre-order, and D-C-N, C-C-N and G-C-N binary relations are partial orders. Furthermore, we discuss relationships among binary relations mentioned above.