Termination of logic programs using semantic unification

Abstract

We introduce a transformation of well-moded logic programs into constructor systems, a subclass of term rewrite systems, such that left-termination of the logic program follows from termination of the derived constructor system. Thereafter, we present a new technique to prove termination of constructor systems. In the technique semantic unification is used. Thus, surprisingly, semantic unification can be used For giving termination proofs for logic programs. Parts of the technique can be automated very easily. Other parts can be automated for subclasses of constructor systems. The technique is powerful enough to prove termination of some constructor systems that are not simply terminating, and therefore, the technique is suitable to prove termination of some difficult logic programs.