2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/176441In the recent successful applications of the non-Abelian discrete symmetry A_4 to the tribimaximal mixing of neutrinos, lepton doublets and singlets do not transform in the same way. It appears thus to be unsuitable as a family symmetry in grand unification. A simple resolution of this dilemma is proposed.6 pages, no figureHigh Energy Physics - Phenomenologytext