Narrowing, abstraction and constraints for proving properties of reduction relations

Abstract

We describe in this paper an inductive proof method for properties of reduction relations. The reduction trees are simulated with proof trees generated by narrowing and an abstraction mechanism. While narrowing simulates reduction, abstraction relies on the induction principle to replace subterms by variables representing specific reduced forms that trivially satisfy the property to be proved. The induction ordering is not given a priori, but defined with ordering constraints, incrementally set during the proof. Abstraction constraints are used to control the narrowing mechanism, well-known to easily diverge. The proof method is briefly illustrated on various examples of properties. © Springer-Verlag Berlin Heidelberg 2007.