Lepton Family Symmetry and Possible Application to the Koide Mass Formula

A finite group generated by four Z_3 transformations is applied to lepton families in a supersymmetric model, resulting in the charged-lepton masses m_i being proportional to v_i^2, where v_i are three vacuum expectation values. This may be relevant in obtaining the Koide formula m_e + m_mu + m_tau = (2/3)(sqrt{m_e} + sqrt{m_mu} + sqrt(m_tau})^2.