Herschend-Liu-Nakaoka introduced the notion of n-exangulated categories. It
is not only a higher dimensional analogue of extriangulated categories defined
by Nakaoka-Palu, but also gives a simultaneous generalization of n-exact
categories and (n+2)-angulated categories. In this article, we give an
n-exangulated version of Auslander's defect and Auslander-Reiten duality
formula. Moreover, we also give a classification of substructures (=closed
subbifunctors) of a given skeletally small n-exangulated category by using
the category of defects.Comment: 24 pages. arXiv admin note: text overlap with arXiv:1709.06689 by
other author