Some new concepts in switching theory are pre sented. One of these is called an "abridged minterm base." We can use an abridged minterm base instead of the minterm expansion in conventional absolute minimization procedures. Since an abridged minterm base almost always has much fewer minterms than are in the minterm expansion, we can derive an abridged minterm base for many functions for which it is impossible to derive the minterm expansion. This paper also introduces the concept of generalized inclusion function Q(f) and its decomposition theorem Q(g)·Q(h) = Q(g V h). The theorem is very useful.

A theorem about conditionally eliminable prime implicants presented by Chang and Mott1is shown to be incorrect by counterexample.

An algorithm for finding a minimal irredundant disjunctive form representation for an incompletely specified multiple-output switching function presented by P. Tison1is shown to be incorrect by counterexample and corrected.