Herschend-Liu-Nakaoka introduced the notion of n -exangulated categories. It is not only a higher dimensional analogue extriangulated categories defined by Nakaoka-Palu, but also gives simultaneous generalization -exact in sense Jasso and ( + 2 ) -angulated Geiss-Keller-Oppermann. Let C be an category with enough projectives injectives, X cluster tilting subcategory . In this article, we show t...

Let $mathcal {A}$ be an abelian category with enough projective objects and $mathcal {X}$ be a full subcategory of $mathcal {A}$. We define Gorenstein projective objects with respect to $mathcal {X}$ and $mathcal{Y}_{mathcal{X}}$, respectively, where $mathcal{Y}_{mathcal{X}}$=${ Yin Ch(mathcal {A})| Y$ is acyclic and $Z_{n}Yinmathcal{X}}$. We point out that under certain hypotheses, these two G...

‎We firstly prove the completeness of the category of crossed modules in a modified category of interest‎. ‎Afterwards‎, ‎we define pullback crossed modules and pullback cat objects that are both obtained by pullback diagrams with extra structures on certain arrows‎. ‎These constructions unify many corresponding results for the cases of groups‎, ‎commutative algebras and can also be adapted to ...