By means of a supporting transformation that dynamically introduces new predicates and their definitions, we can overcome the restrictions caused by these conditions. A partial evaluation will, in general, contain redundant functions and unnecessary repetition of variables. This can cause inefficiency in the use of space and time by the transformed program. The second supporting transformation described here cleans up a partial evaluation removing any unnecessary symbols."

This volume contains the papers from the Seventh International Workshop on Logic Program Synthesis and Transformation, LOPSTR '97, that took place in Leuven, Belgium, on July 10–12, 1997, 'back to back' with the Fourteenth International Conference on Logic Programming, ICLP '97. Both ICLP and LOPSTR were organised by the K.U. Leuven Department of Computer Science. LOPSTR '97 was sponsored by Compulog Net and by the Flanders Research Network on Declarative Methods in Computer Science. LOPSTR '97 had 39 participants from 13 countries. There were two invited talks by Wolfgang Bibel (Darmstadt) on 'A multi level approach to program synthesis', and by Henning Christiansen (Roskilde) on 'Implicit program synthesis by a reversible metainterpreter'. Extended versions of both talks appear in this volume. There were 19 technical papers accepted for presentation at LOPSTR '97, out of 33 submissions. Of these, 15 appear in extended versions in this volume. Their topics range over the fields of program synthesis, program transformation, program analysis, tabling, metaprogramming, and inductive logic programming.

This volume contains selected papers from LOPSTR 2003, the 13th Inter- tional Symposium on Logic-Based Program Synthesis and Transformation. The LOPSTR series is devoted to research in logic-based program development. P- ticular topics of interest are speci?cation, synthesis, veri?cation, transformation, specialization, analysis, optimization, composition, reuse, component-based so- ware development, agent-based software development, software architectures, design patterns and frameworks, program re?nement and logics for re?nement, proofs as programs, and applications and tools. LOPSTR 2003 took place at the University of Uppsala from August 25 to August 27 as part of PLI 2003 (Principles, Logics, and Implementations of High- Level Programming Languages). PLI was an ACM-organized confederation of conferences and workshops with ICFP 2003 (ACM-SIGPLAN International C- ference on Functional Programming) and PPDP 2003 (ACM-SIGPLAN Inter- tional Conference on Principles and Practice of Declarative Programming) as the main events. The LOPSTR community pro?ted from the shared lectures of the invited speakers, and the active scienti?c discussions enabled by the co-location. LOPSTR 2003 was the thirteenth in a series of events. Past events were held in Manchester, UK (1991, 1992, 1998), Louvain-la-Neuve, Belgium (1993), Pisa, Italy (1994), Arnhem, The Netherlands (1995), Stockholm, Sweden (1996), L- ven, Belgium (1997), Venice, Italy (1999), London, UK (2000), Paphos, Cyprus (2001), and Madrid, Spain (2002).

Logic program synthesis and transformation are topics of central importance to the software industry. The demand for software can not be met by the current supply, in terms of volume, complexity, or reliability. The most promising solution seems to be the increased automation of software production: programmer productivity would improve, and correctness could be ensured by the application of mathematical methods. Because of their mathematical foundations, logic programs lend themselves particularly well to machine-assisted development techniques, and therefore to automation. This volume contains the proceedings of the second International Workshop on Logic Program Synthesis and Transformation (LOPSTR 92), held at the University of Manchester, 2-3 July 1992. The LOPSTR workshops are the only international meetings devoted to these two important areas. A variety of new techniques were described at the workshop, all of which promise to revolutionize the software industry once they become standard practise. These include techniques for the transformation of an inefficient program into an equivalent, efficient one, and the synthesis of a program from a formal specification of its required behaviour. Among the topics covered in this volume are: optimal transformation of logic programs; logic program synthesis via proof planning; deductive synthesis of programs for query answering; efficient compilation of lazy narrowing into Prolog; synthesis of narrowing programs; Logimix: a self-applicable partial evaluator for Prolog; proof nets; automatic termination analysis. Logic Program Synthesis and Transformation describes the latest advances in machine-assisted development of logic programs. It will provide essential reading for researchers and postgraduate students concerned with these two important areas.

Logic programming synthesis and transformation are methods of deriving logic programs from their specifications and, where necessary, producing alternative but equivalent forms of a given program. The techniques involved in synthesis and transformation are extremely important as they allow the systematic construction of correct and efficient programs and have the potential to enhance current methods of software production. Transformation strategies are also being widely used in the field of logic program development. LOPSTR 91 was the first workshop to deal exclusively with both logic program synthesis and transformation and, as such, filled an obvious gap in the existing range of logic programming workshops. In attempting to cover the subject as comprehensively as possible, the workshop brought together researchers with an interest in all aspects of logic (including Horn Clause and first order logic) and all approaches to program synthesis and transformation. Logic Program Synthesis and Transformation provides a complete record of the workshop, with all the papers reproduced either in full or as extended abstracts. They cover a wide range of aspects, both practical and theoretical, including the use of mode input-output in program transformation, program specification and synthesis in constructive formal systems and a case study in formal program development in modular Prolog. This volume provides a comprehensive overview of current research and will be invaluable to researchers and postgraduate students who wish to enhance their understanding of logic programming techniques.