2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/69684The aim of the paper is to discuss the relations between the three kinds of objects named in the title. In a sense, this is a survey of such relations; however, some new directions are also considered. This relates, especially, to sections 3, 4 and 5, where we consider the universal algebraic geometry. This geometry is parallel to universal algebra.62ppGeneral MathematicsCategory Theory03C05, 03G99, 16B70, 08A70text