On Sahlqvist Formulas in Relevant Logic.

This paper defines a Sahlqvist fragment for relevant logic and establishes that each class of frames in the Routley-Meyer semantics which is definable by a Sahlqvist formula is also elementary, that is, it coincides with the class of structures satisfying a given first order property calculable by a...

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Detalles Bibliográficos
Publicado en:	Journal of Philosophical Logic Vol. 47; no. 4; pp. 673 - 692
Autor principal:	Badia, Guillermo
Formato:	Artículo
Publicado:	Springer Nature Aug2018
Materias:	Relevance logic Mathematical analysis Theory of knowledge Definability theory (Mathematical logic) Semantics
Acceso en línea:	Ver este registro en EBSCOhost

Descripción
Sumario:	This paper defines a Sahlqvist fragment for relevant logic and establishes that each class of frames in the Routley-Meyer semantics which is definable by a Sahlqvist formula is also elementary, that is, it coincides with the class of structures satisfying a given first order property calculable by a Sahlqvist-van Benthem algorithm. Furthermore, we show that some classes of Routley-Meyer frames definable by a relevant formula are not elementary.