Find the non-dominated point of a set (minima of a point set).
nondom(x, ...)
matrix
A point x dominates y if it is never worse and at least in one case strictly better. Formally, let f_i denote the ith coordinate of the condition (objective) function, then for all i: f_i(x)<=f_i(y) and there exists j: f_j(x)<f_j(y).
Based on the algorithm of Kung et al. 1975.