A fully labelled proof system for intuitionistic modal logics
Résumé
Labelled proof theory has been famously successful for modal logics by mimicking their relational seman-
tics within deductive systems. Simpson in particular designed a framework to study a variety of intuitionistic
modal logics integrating a binary relation symbol in the syntax. In this paper, we present a labelled sequent
system for intuitionistic modal logics such that there is not only one, but two relation symbols appearing
in sequents: one for the accessibility relation associated with the Kripke semantics for normal modal logics
and one for the preorder relation associated with the Kripke semantics for intuitionistic logic. This puts
our system in close correspondence with the standard birelational Kripke semantics for intuitionistic modal
logics. As a consequence it can be extended with arbitrary intuitionistic Scott-Lemmon axioms. We show
soundness and completeness, together with an internal cut elimination proof, encompassing a wider array of
intuitionistic modal logics than any existing labelled system.
Domaines
Logique en informatique [cs.LO]Origine | Fichiers produits par l'(les) auteur(s) |
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