2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/218254We show that the class of Metropolis-Rota implication algebras can be given a universal axiomatization using an operation closely related to composition in oriented matroids. Lastly we describe the role of our new operation in the collapse of an MR-algebra.14 pagesCombinatorics06A06 (primary), 06E99 (secondary)text