2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/39597It is shown that the bi-maximal solution is the only possibility to reconcile Zee-type neutrino mass matrix with three flavors to the current atmospheric and solar neutrino experimental data. The mass of the lightest neutrino, which consist mostly of $ν_μ$ and $ν_τ$, is $\simeq Δm_{\odot}^2/(2\sqrt{Δm_{atm}^2})$. The related topics on Zee-type neutrino mass matrix are also discussed.5 pages, no figure, Talk given by M. Matsuda at Workshop on Neutrino Oscillations and their Origin, Fuji-Yoshida, Japan, 11-13 Feb 2000High Energy Physics - Phenomenologytext