3rd International Workshop on Reduction Strategies in Rewriting and Programming (WRS 2003) - Final Proceedings

The preliminary proceedings of WRS 2003 have been published as Technical Report DSIC-II/14/03 of the Universidad Politécnica de Valencia.

Reduction strategies in rewriting and programming have attracted an increasing attention within the last years. New types of reduction strategies have been invented and investigated, and new results on rewriting/computation under particular strategies have been obtained. Research in this field ranges from primarily theoretical questions about reduction strategies to very practical application and implementation issues. The need for a deeper understanding of reduction strategies in rewriting and programming, both in theory and practice, is obvious, since they bridge the gap between unrestricted general rewriting (computation) and (more deterministic) rewriting with particular strategies (programming). Moreover, reduction strategies provide a natural way to go from operational principles (e.g., graph and term rewriting, narrowing, lambda-calculus) and semantics (e.g., normalization, computation of values, infinitary normalization, head-normalization) to implementations of programming languages. Therefore any progress in this area is likely to be of interest not only to the rewriting community, but also to neighbouring fields like functional programming, functional-logic programming, and termination proofs of algorithms. WRS 2003 is the third edition in a series of workshops intended to stimulate and promote research and progress in this important field. The workshop wants to provide a forum for the presentation and discussion of new ideas and results, recent developments, new research directions, as well as of surveys on existing knowledge in this area. Furthermore we aim at fostering interaction and exchange between researchers and students actively working on such topics. Previous WRS editions took place in Utrecht (The Netherlands) in 2001 (WRS 2001) and in Copenhagen (Denmark) in 2002 (WRS 2002).

Topics of interest for the workshop included, but were not restricted to,

• theoretical foundations for the definition and semantic description of reduction strategies,

• strategies in different frameworks (term rewriting, graph rewriting, infinitary rewriting, lambda calculi, higher order rewriting and explicit substitutions, conditional rewriting, rewriting with built-ins, narrowing, constraint solving, etc.) and their application in (equational, functional, functional-logic) programming (languages),

• properties of reduction strategies/computations under strategies (e.g., completeness, computability, decidability, complexity, optimality, (hyper-)normalization, cofinality, fairness, perpetuality, context-freeness, neededness, laziness, eagerness, strictness),

• interrelations, combinations and applications of reduction under different strategies (e.g., equivalence conditions for fundamental properties like termination and confluence, applications in modularity analysis, connections between strategies of different frameworks, etc.),

• program analysis and other semantics-based optimization techniques dealing with reduction strategies,

• rewrite systems/tools/implementations with flexible/programmable strategies as essential concept/ingredient,

• specification of reduction strategies in (real) languages,

• data structures and implementation techniques for reduction strategies.

The program committee received nine submissions for WRS 2003. After the workshop, authors of accepted papers were invited to submit revised versions for the final ENTCS proceedings of WRS 2003. Based on the careful and thorough reviewing process for the workshop and on a subsequent second round of reviewing for the revised ENTCS submissions, the following six regular papers were accepted for inclusion in the final post-workshop proceedings, published in this issue of Electronic Notes in Theoretical Computer Science:

• Weak Reduction and Garbage Collection in Interaction Nets by Jorge Sousa Pinto

• Simulating Liveness by Reduction Strategies by Jürgen Giesl and Hans Zantema

• Call-by-Value, Call-by-Name, and Strong Normalization for the Classical Sequent Calculus by Stéphane Lengrand

• A Rewriting Strategy for Protocol Verification by Monica Nesi, Giuseppina Rucci and Massimo Verdesca

• Call-by-Need Reductions for Membership Conditional Term Rewriting Systems by Mizuhito Ogawa

• An Abstract Concept of Optimal Implementation by Zurab Khasidashvili and John Glauert

Furthermore, this issue also contains the following two invited papers by Manuel Claveland by Claude Kirchner

• Strategies and User Interfaces in Maude at Work by Manuel Clavel

• Rewrite Strategies in the Rewriting Calculus by Horatiu Cirstea, Claude Kirchner, Luigi Liquori and Benjamin Wack

Program Committee of WRS 2003

Additional External Referees

Thomas Genet, Sebastien Limet, Sarah Mocas, Monica Nesi, and Vincent van Oostrom.

Local Organization

María Alpuente, Salvador Lucas (chair), Javier Oliver, María José Ramírez, Germán Vidal, and the whole ELP group at the Universidad Politécnica de Valencia.

We would like to thank the invited speakers for their willingness to accept our invitation. Regarding the reviewing process we are very grateful to the members of the program committee as well as to the additional external referees for their careful reviewing work. Furthermore we wish to express our gratitude to all members of the local Organizing Committee for providing a very pleasant venue and frame for holding WRS 2003 as part of RDP 2003. Finally, we would also like to thank Michael Mislove, Managing Editor of the ENTCS series, for his technical assistance concerning the ENTCS format.

December 5, 2003

Bernhard Gramlich and Salvador Lucas.