Proving termination of logic programs with delay declarations

In this paper we propose a method for proving termination of logic programs with delay declarations. The method is based on the notion of recurrent logic program, which is used to prove programs terminating wrt an arbitrary selection rule. Most importantly, we use the notion of bound query (as proposed by M. Bezem) in the definition of cover, a new notion which forms the kernel of our approach. We introduce the class of delay recurrent programs and prove that programs in this class terminate for all local delay selection rules, provided that the delay conditions imply boundedness. The corresponding method can be also used to transform a logic program into a terminating logic program with delay declarations

Generating Efficient, Terminating Logic Programs

The objective of control generation in logic programming is to automatically derive a computation rule for a program that is efficient and yet does not compromise program correctness. Progress in solving this important problem has been slow and, to date, only partial solutions have been proposed where the generated programs are either incorrect or inefficient. We show how the control generation problem can be tackled with a simple automatic transformation that relies on information about the depths of derivations. To prove correctness of our transform we introduce the notion of a semi delay recurrent program which generalises previous ideas in the termination literature for reasoning about logic programs with dynamic selection rules

A Polyvariant Binding-Time Analysis for Off-line Partial Deduction

We study the notion of binding-time analysis for logic programs. We formalise the unfolding aspect of an on-line partial deduction system as a Prolog program. Using abstract interpretation, we collect information about the run-time behaviour of the program. We use this information to make the control decisions about the unfolding at analysis time and to turn the on-line system into an off-line system. We report on some initial experiments.Comment: 19 pages (including appendix) Paper (without appendix) appeared in Programming Languages and Systems, Proceedings of the European Symposium on Programming (ESOP'98), Part of ETAPS'98 (Chris Hankin, eds.), LNCS, vol. 1381, 1998, pp. 27-4

Verifying termination and error-freedom of logic programs with block declarations

We present verification methods for logic programs with delay declarations. The verified properties are termination and freedom from errors related to built-ins. Concerning termination, we present two approaches. The first approach tries to eliminate the well-known problem of speculative output bindings. The second approach is based on identifying the predicates for which the textual position of an atom using this predicate is irrelevant with respect to termination. Three features are distinctive of this work: it allows for predicates to be used in several modes; it shows that block declarations, which are a very simple delay construct, are sufficient to ensure the desired properties; it takes the selection rule into account, assuming it to be as in most Prolog implementations. The methods can be used to verify existing programs and assist in writing new programs

Termination of logic programs with delay declarations

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Proving termination of logic programs with delay declarations

Contains fulltext : 84491.pdf (author's version ) (Open Access)International Logic Programming Symposium (ILPS'95