Flow Table Simplification-Some Useful Aids

Three results are presented pertinent to the problem of finding minimum-row versions of incompletely specified flow tables for sequential or iterative circuits. 1) Conditions are precisely stated under which preliminary mergers can be made without the danger of ruining opportunities for ultimately finding a minimal-row version. 2) A theorem by McCluskey is generalized to show that for all flow tables if optional entries arise only due to restrictions as to which input states may immediately follow one another, then the reduction problem is relatively simple. 3) A useful heuristic in the form of a diagram illustrating implication relations of 2-member compatibles is introduced as an aid in finding minimal closed sets of compatibles.