Large lepton mixing in a coset-space family unification on E7/SU(5)×U(1)3

We study a coset-space unification model for families based on E7/SU(5)×U(1)3. We find that qualitative structure of quark and lepton mass matrices in this model describes very well the observation. We stress, in particular, that the large mixing angle, sin22θνμντ≃1, required for the atmospheric neutrino oscillation reported by the SuperKamiokande collaboration, is naturally obtained, which is a consequence of unparallel family structure in the present coset-space unification.