If the solar and atmospheric neutrino deficits and the apparent need for a hot dark matter component all result from neutrino mass, one of three neutrino mass patterns is required. Of these, two appear quite unlikely, leading to a unique solution which points to further experimental tests. We briefly outline possible theoretical models which could generate these three neutrino mass matrices without adjustment of parameters.

• Received 17 March 1993

DOI:https://doi.org/10.1103/PhysRevD.48.3259