A cut-free sequent system for two-dimensional modal logic, and why it matters

G. Restall

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

The two-dimensional modal logic of Davies and Humberstone (1980). [3] is an important aid to our understanding the relationship between actuality, necessity and a priori knowability. I show how a cut-free hypersequent calculus for 2D modal logic not only captures the logic precisely, but may be used to address issues in the epistemology and metaphysics of our modal concepts. I will explain how the use of our concepts motivates the inference rules of the sequent calculus, and then show that the completeness of the calculus for Davies-Humberstone models explains why those concepts have the structure described by those models. The result is yet another application of the completeness theorem.
Original languageEnglish
Pages (from-to)1611-1623
Number of pages13
JournalAnnals of Pure and Applied Logic
Volume163
Issue number11
Early online date26 Dec 2011
DOIs
Publication statusPublished - Nov 2012

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Modal Logic
Completeness
Calculus
Epistemology
Sequent Calculus
Inference Rules
Logic
Theorem
Model
Concepts

Cite this

A cut-free sequent system for two-dimensional modal logic, and why it matters. / Restall, G.

In: Annals of Pure and Applied Logic, Vol. 163, No. 11, 11.2012, p. 1611-1623.

Research output: Contribution to journalArticle

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