2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/185337The naturalness of maximal mixing between myon- and tau-neutrinos is investigated. A spontaneously broken nonabelian generation symmetry can explain a small parameter which governs the deviation from maximal mixing. In many cases all three neutrino masses are almost degenerate. Maximal ny_my-ny_tau-mixing would indicate that the leading contribution to the light neutrino masses arises from the expectation value of a heavy weak triplet rather than from the seesaw mechanism. In this scenario the deviation from maximal mixing is predicted to be less than about 1%.13 pages,LaTexHigh Energy Physics - Phenomenologytext