Strong and weak operational termination of order-sorted rewrite theories
This paper presents several new results on conditional term rewriting within the general framework of order-sorted rewrite theories (OSRTs) which contains the more restricted framework of conditional term rewriting systems (CTRSs) as a special case. The results uncover some subtle issues about condi...
| Autores: | , |
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| Tipo de recurso: | capítulo de libro |
| Fecha de publicación: | 2014 |
| País: | España |
| Institución: | Universitat Politècnica de València (UPV) |
| Repositorio: | RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia |
| Idioma: | inglés |
| OAI Identifier: | oai:riunet.upv.es:10251/50899 |
| Acceso en línea: | https://riunet.upv.es/handle/10251/50899 |
| Access Level: | acceso abierto |
| Palabra clave: | Conditional term rewriting Strong and weak operational termination Irreducible terms Normalized terms Rewriting logic Maude LENGUAJES Y SISTEMAS INFORMATICOS |
| Sumario: | This paper presents several new results on conditional term rewriting within the general framework of order-sorted rewrite theories (OSRTs) which contains the more restricted framework of conditional term rewriting systems (CTRSs) as a special case. The results uncover some subtle issues about conditional termination. We first of all generalize a previous known result characterizing the operational termination of a CTRS by the quasi-decreasing ordering notion to a similar result for OSRTs. Second, we point out that the notions of *irreducible* term and of *normal form*, which coincide for unsorted rewriting are *totally different* for conditional rewriting and formally characterize that difference. We then define the notion of a *weakly operationally terminating* (or *weakly normalizing*) OSRT, give several evaluation mechanisms to compute normal forms in such theories, and investigate general conditions under which the rewriting-based operational semantics and the initial algebra semantics of a confluent OSRT coincide thanks to a notion of *canonical term algebra*. Finally, we investigate appropriate conditions and proof methods to ensure good executability properties of an OSRT for computing normal forms. |
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