Minimal Input Solutions

Abstract

Logic design problems that have inessential variables as inputs are often encountered. The required logic can be implemented without the use of these inessential variables. Such variables occur most frequently in incompletely specified functions due to the presence of DON'T CARE conditions. A circuit with a minimal number of inputs would simplify many interconnection problems. This note presents a method that treats each inessential variable as a simple disjunctive decomposition. This treatment leads to a method of identifying and removing a maximal set of inessential variables, and the removal results in a minimal input solution.