NARROWING STRATEGIES FOR ARBITRARY CANONICAL REWRITE SYSTEMS

Article type: Research Article

Authors: Bockmayr, Alexander | Krischer, Stefan | Werner, Andreas

Note: [] MPI Informatik, Im Stadtwald, D-66123 Saarbrücken, bockmayr@mpi-sb.mpg.de

Note: [] CRIN & INRIA-Lorraine, B.P.239, F-54506 Vandoeuvre-lès-Nancy, krischer@loria.fr

Note: [] SFB 314, Univ. Karlsruhe, D-76128 Karlsruhe, werner@ira.uka.de

Abstract: Narrowing is a universal unification procedure for equational theories defined by a,canonical term rewriting system. In its original form it is extremely inefficient. Therefore, many optimizations have been proposed during the last years. In this paper, we present the narrowing strategies for arbitrary canonical systems in a uniform framework and introduce the new narrowing strategy LSE narrowing. LSE narrowing is complete and improves all other strategies which are complete for arbitrary-canonical systems. It is optimal in the sense that two different LSE narrowing derivations cannot generate the same narrowing substitution. Moreover, LSE narrowing computes only normalized narrowing substitutions.

DOI: 10.3233/FI-1995-24126

Journal: Fundamenta Informaticae, vol. 24, no. 1-2, pp. 125-155, 1995