2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/228147The origin of neutrino mass is usually attributed to a seesaw mechanism, either through a heavy Majorana fermion singlet (version 1) or a heavy scalar triplet (version 2). Recently, the idea of using a heavy Majorana fermion triplet (version 3) has gained some attention. This is a review of the basic idea involved, its U(1) gauge extension, and some recent developments.8 pages, 4 figures, talk at XIII Mexican School of Particles and Fields, San Carlos, Sonora, Mexico, Oct 2008High Energy Physics - Phenomenologytext