2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/124518We study the relationship between the loop problem of a semigroup, and that of a Rees matrix construction (with or without zero) over the semigroup. This allows us to characterize exactly those completely zero-simple semigroups for which the loop problem is context-free. We also establish some results concerning loop problems for subsemigroups and Rees quotients.13 pagesRings and Algebras20M05, 20M35, 68Q70text