The Only 3-Valued Logic Which Is a Natural Implication Expansion with the Variable-Sharing Property of Kleene’s Strong Logic

[EN] Let us refer by MK3 to Kleene’s strong 3-valued matrix. An implicative expansion of MK3 is natural if the conditional function defining it verifies modus ponens, assigns a designated value to a conditional whenever it assigns the same value to its antecedent and its consequent, and, finally, it...

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Detalles Bibliográficos
Autores: Robles Vázquez, Gemma, Méndez Rodríguez, José Manuel
Tipo de recurso: capítulo de libro
Estado:Versión aceptada para publicación
Fecha de publicación:2025
País:España
Institución:Universidad de León
Repositorio:BULERIA. Repositorio Institucional de la Universidad de León
OAI Identifier:oai:buleria.unileon.es:10612/25671
Acceso en línea:https://link.springer.com/chapter/10.1007/978-3-031-69940-5_10
https://hdl.handle.net/10612/25671
Access Level:acceso abierto
Palabra clave:Lógica
Three-valued logics
Kleene’s strong logic
Natural conditionals
Variable-sharing property
Relevant logics
11 Lógica
Descripción
Sumario:[EN] Let us refer by MK3 to Kleene’s strong 3-valued matrix. An implicative expansion of MK3 is natural if the conditional function defining it verifies modus ponens, assigns a designated value to a conditional whenever it assigns the same value to its antecedent and its consequent, and, finally, it coincides with the classical conditional function when restricted to the “classical” values t and f. Two are the main results of this paper. (1) It is proven that, from the viewpoint of functional strength, there is only one 3-valued natural implication expansion of MK3 with the variable-sharing property, the logic we dub L3^{VSP}. (2) It is shown that L3^{VSP} is a significant and strong logic that can be seen from different perspectives, one of them being to consider it an expansion of classical positive propositional logic.