Local confluence of conditional and generalized term rewriting systems

[EN] Reduction-based systems are used as a basis for the implementation of programming languages, automated reasoning systems, mathematical analysis tools, etc. In such inherently non deterministic systems, guaranteeing that diverging steps can be eventually rejoined is crucial for a faithful use in...

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Detalhes bibliográficos
Autor: Lucas Alba, Salvador|||0000-0001-9923-2108
Formato: artículo
Fecha de publicación:2024
País:España
Recursos:Universitat Politècnica de València (UPV)
Repositorio:RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia
Idioma:inglés
OAI Identifier:oai:riunet.upv.es:10251/204334
Acesso em linha:https://riunet.upv.es/handle/10251/204334
Access Level:acceso abierto
Palavra-chave:Conditional rewriting
Confluence
First-order logic
LENGUAJES Y SISTEMAS INFORMATICOS
Descrição
Resumo:[EN] Reduction-based systems are used as a basis for the implementation of programming languages, automated reasoning systems, mathematical analysis tools, etc. In such inherently non deterministic systems, guaranteeing that diverging steps can be eventually rejoined is crucial for a faithful use in most applications. This property of reduction systems is called local confluence. In a landmark 1980 paper, Gerard Huet characterized local confluence of a Term Rewriting System as the joinability of all its critical pairs. In this paper, we characterize local confluence of Conditional Term Rewriting Systems, where reduction steps may depend on the satisfaction of specific conditions in rules: a conditional term rewriting system is locally confluent if and only if (i) all its conditional critical pairs and (ii) all its conditional variable pairs (which we introduce in this paper) are joinable. Furthermore, the logic-based approach we follow here is well-suited to analyze local confluence of more general reduction-based systems. We exemplify this by (i) including (context-sensitive) replacement restrictions in the arguments of function symbols, and (ii) allowing for more general conditions in rules. The obtained systems are called Generalized Term Rewriting Systems. A characterization of local confluence is also given for them.