Co-∗n-modules

Abstract

It is well known that the notion of ∗-modules plays an important role in the generalization of Morita equivalences. Recently, Wei et al. introduced the concept of ∗n-modules, which induces an equivalence of particular subcategories. In this paper, the dual situation of ∗n-modules, called co -∗n-modules, is considered, and their characterizations and properties are derived. We also present a characterization in terms of category duality, which can be regarded as a generalization of Morita duality. In particular, it is found that the co -selfsmall n-cotilting modules are co -∗n-modules.