“…Criterion (21) can easily be generalized to the case of the multicomponent system: (22) where N is the number of the mixture components, m j = -∂F/∂C j , F = F(C 1 , C 2 , …), and C j , k j , and D j are the concentrations of the impurity, the coefficients of its distribution, and the diffusion coefficients for the jth component. A number of important features of the theory being developed are also worth noting.…”