A Reduction-Preserving Completion for Proving Confluence of Non-Terminating Term Rewriting Systems

We give a method to prove confluence of term rewriting systems that contain non-terminating rewrite rules such as commutativity and associativity. Usually, confluence of term rewriting systems containing such rules is proved by treating them as equational term rewriting systems and considering E-cri...

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Main Authors: Takahito Aoto, Yoshihito Toyama
Format: Article
Language:English
Published: Logical Methods in Computer Science e.V. 2012-03-01
Series:Logical Methods in Computer Science
Subjects:
Online Access:https://lmcs.episciences.org/667/pdf
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author Takahito Aoto
Yoshihito Toyama
author_facet Takahito Aoto
Yoshihito Toyama
author_sort Takahito Aoto
collection DOAJ
description We give a method to prove confluence of term rewriting systems that contain non-terminating rewrite rules such as commutativity and associativity. Usually, confluence of term rewriting systems containing such rules is proved by treating them as equational term rewriting systems and considering E-critical pairs and/or termination modulo E. In contrast, our method is based solely on usual critical pairs and it also (partially) works even if the system is not terminating modulo E. We first present confluence criteria for term rewriting systems whose rewrite rules can be partitioned into a terminating part and a possibly non-terminating part. We then give a reduction-preserving completion procedure so that the applicability of the criteria is enhanced. In contrast to the well-known Knuth-Bendix completion procedure which preserves the equivalence relation of the system, our completion procedure preserves the reduction relation of the system, by which confluence of the original system is inferred from that of the completed system.
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spelling doaj.art-3420baaff54142d9b5e13ce33e6e249c2024-03-08T09:27:54ZengLogical Methods in Computer Science e.V.Logical Methods in Computer Science1860-59742012-03-01Volume 8, Issue 110.2168/LMCS-8(1:31)2012667A Reduction-Preserving Completion for Proving Confluence of Non-Terminating Term Rewriting SystemsTakahito AotoYoshihito ToyamaWe give a method to prove confluence of term rewriting systems that contain non-terminating rewrite rules such as commutativity and associativity. Usually, confluence of term rewriting systems containing such rules is proved by treating them as equational term rewriting systems and considering E-critical pairs and/or termination modulo E. In contrast, our method is based solely on usual critical pairs and it also (partially) works even if the system is not terminating modulo E. We first present confluence criteria for term rewriting systems whose rewrite rules can be partitioned into a terminating part and a possibly non-terminating part. We then give a reduction-preserving completion procedure so that the applicability of the criteria is enhanced. In contrast to the well-known Knuth-Bendix completion procedure which preserves the equivalence relation of the system, our completion procedure preserves the reduction relation of the system, by which confluence of the original system is inferred from that of the completed system.https://lmcs.episciences.org/667/pdfcomputer science - logic in computer scienced.3.1, f.3.1, f.4.2, i.2.2
spellingShingle Takahito Aoto
Yoshihito Toyama
A Reduction-Preserving Completion for Proving Confluence of Non-Terminating Term Rewriting Systems
Logical Methods in Computer Science
computer science - logic in computer science
d.3.1, f.3.1, f.4.2, i.2.2
title A Reduction-Preserving Completion for Proving Confluence of Non-Terminating Term Rewriting Systems
title_full A Reduction-Preserving Completion for Proving Confluence of Non-Terminating Term Rewriting Systems
title_fullStr A Reduction-Preserving Completion for Proving Confluence of Non-Terminating Term Rewriting Systems
title_full_unstemmed A Reduction-Preserving Completion for Proving Confluence of Non-Terminating Term Rewriting Systems
title_short A Reduction-Preserving Completion for Proving Confluence of Non-Terminating Term Rewriting Systems
title_sort reduction preserving completion for proving confluence of non terminating term rewriting systems
topic computer science - logic in computer science
d.3.1, f.3.1, f.4.2, i.2.2
url https://lmcs.episciences.org/667/pdf
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