The core and dual core inverse of a morphism with factorization

Abstract

Let $\mathscr{C}$ be a category with an involution $\ast$. Suppose that $\varphi : X \rightarrow X$ is a morphism and $(\varphi_1, Z, \varphi_2)$ is an (epic, monic) factorization of $\varphi$ through $Z$, then $\varphi$ is core invertible if and only if $(\varphi^{\ast})^2\varphi_1$ and $\varphi_2\varphi_1$ are both left invertible if and only if $((\varphi^{\ast})^2\varphi_1, Z, \varphi_2)$, $(\varphi_2^{\ast}, Z, \varphi_1^{\ast}\varphi^{\ast}\varphi)$ and $(\varphi^{\ast}\varphi_2^{\ast}, Z, \varphi_1^{\ast}\varphi)$ are all essentially unique (epic, monic) factorizations of $(\varphi^{\ast})^2\varphi$ through $Z$. We also give the corresponding result about dual core inverse. In addition, we give some characterizations about the coexistence of core inverse and dual core inverse of an $R$-morphism in the category of $R$-modules of a given ring $R$.