Applications of reduced and coreduced modules II: Radicality of the functor $\text{Hom}_R(R/I, -)$

Abstract: This is the second in a series of papers highlighting the applications of reduced and coreduced modules. Let $R$ be a commutative unital ring and $I$ be an ideal of $R$. We give necessary and sufficient conditions in terms of $I$-reduced and $I$-coreduced $R$-modules for the functor $\text{Hom}_R(R/I, -)$ on the abelian full subcategory of the category of $R$-modules to be a radical. These conditions further provide a setting for the generalisation of Jans' correspondence, and lead to a new radical class of rings.