Approximating Symmetric Relations by Equivalence Relations
C. T. Zahn · Journal of the Society for Industrial and Applied Mathematics · 1964
The problem of finding an equivalence relation E, which “best approximates” a given symmetric relation R in the sense of minimizing the number of elements of $( E - R) \cup ( R - E)$, is solved for a class of relations R representing two-level and three-level “hierarchical” structures.