Using if-then-else DAGs for multi-level logic minimization
Kevin J. Karplus · 1989
This article describes the use of if-then-else dags for multi-level logic minimization. A new canonical form for if-then-else dags, analogous to Bryant's canonical form for binary decision diagrams (bdds), is introduced. Two-cuts are defined for binary decision diagrams, and a relationship is exhibited between general if-then-else expressions and the two-cuts of a bdd for the same function. The canonical form is based on representing the lowest non-trivial two-cut in the corresponding bdd, instead of the highest two-cut, as in Bryant's canonical form. The definitions of prime and irredundant expressions are extended to if-then-else dags.