On the basis of a supersymmetric yukawaon model, Sumino's relation for
charged lepton masses is re-derived. A relation between values of K(μ)≡(me+mμ+mτ)/(me+mμ+mτ)2 and
κ(μ)≡memμmτ/(me+mμ+mτ)3 is investigated without using a relation K=2/3. Predicted
value of κ(μ) is compared with the observed value of κ(μ),
and it is concluded that the value ξ(μ)≡(3/2)K(μ)−1 is of the
order of 10−3 or less.Comment: 14 pages, 3 figures, version accepted by PL