Weighting Method for the Determination of the Irredundant Set of Prime Implicants

A complete or restricted set of prime implicants (PI's) can cover the terms of the switching function with more or less redundancy. In order to find an irredundant form from the set of PI's, it is necessary to choose those PI's which contribute most effectively towards the strict minimum sum. The criterion for the right choice of the PI's is their weight from the point of view of their cost and their ability to cover a maximum number of switching terms. This criterion assures the simplicity of the switching circuit and helps to increase its reliability. The PI's with the highest weight are chosen.