An approach to minimization that is based on a state-of-the-art paradigm for the two-level minimization of functions is presented. Some special properties of relations, in contrast to functions, which must be carefully considered in realizing a high-quality procedure for solving the minimization problem are clarified. An efficient heuristic method to find an optimal sum-of-products representation for a multiple-valued relation is proposed and implemented in the program GYOCRO. It uses multiple-valued decision diagrams (MDDs) to represent the characteristic functions for the relations. Experimental results are presented and compared with previous exact and heuristic Boolean relation minimizers to demonstrate the effectiveness of the proposed method. >
['Yosinori Watanabe', 'Robert K. Brayton']
Heuristic minimization of multiple-valued relations