Characterization of coextensive varieties of universal algebras

Abstract

A coextensive category can be defined as a category $\mathcal{C}$ with finite products such that for each pair $X,Y$ of objects in $\mathcal{C}$, the canonical functor $\times\colon X/\mathcal{C} \times Y/\mathcal{C} \to (X \times Y)/\mathcal{C}$ is an equivalence. We give a syntactical characterization of coextensive varieties of universal algebras.