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Open AccessJournal ArticleDOI

Modal logics with Belnapian truth values

TLDR
Various four- and three-valued modal propositional logics are studied and axiom systems are defined and shown to be sound and complete with respect to the relational semantics and to twist structures over modal algebras.
Abstract
Various four- and three-valued modal propositional logics are studied. The basic systems are modal extensions BK and BS4 of Belnap and Dunn's four-valued logic of firstdegree entailment. Three-valued extensions of BK and BS4 are considered as well. These logics are introduced semantically by means of relational models with two distinct evaluation relations, one for verification (support of truth) and the other for falsification (support of falsity). Axiom systems are defined and shown to be sound and complete with respect to the relational semantics and with respect to twist structures over modal algebras. Sound and complete tableau calculi are presented as well. Moreover, a number of constructive non-modal logics with strong negation are faithfully embedded into BS4, into its three-valued extension B3S4, or into temporal BS4, BtS4. These logics include David Nelson's three-valued logic N3, the four-valued logic N4 bottom, the connexive logic C, and several extensions of bi-intuitionistic logic by strong ...

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Citations
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Journal ArticleDOI

40 years of FDE: An Introductory Overview

TL;DR: This introduction to the special issue “40 years of FDE” offers an overview of the field and put the papers included in the specialissue into perspective and presents various semantics and proof systems for FDE.
Journal Article

Four-valued modal logic: Kripke semantics and duality.

TL;DR: The aim is to study the least modal logic over the Belnap lattice, that is, the logic determined by the class of all Kripke frames where the accessibility relation as well as semantic valuations are four-valued.
Journal ArticleDOI

Disentangling FDE-Based Paraconsistent Modal Logics

TL;DR: The relationships between various modal logics based on Belnap and Dunn’s paraconsistent four-valued logic FDE are investigated and MBL can be faithfully embedded into the bimodal logic over the non-modal vocabulary of MBL.
Journal ArticleDOI

Four-valued modal logic: Kripke semantics and duality

TL;DR: In this paper, the authors define and axiomatize the least modal logic over the four-element Belnap lattice, which is the logic determined by the class of all Kripke frames where the accessibility relation as well as semantic valuations are four-valued.
References
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Book ChapterDOI

A Useful Four-Valued Logic

TL;DR: It is argued that a sophisticated question-answering machine that has the capability of making inferences from its data base should employ a certain four-valued logic, the motivating consideration being that minor inconsistencies in its data should not be allowed to lead to irrelevant conclusions.
Book

Modal Logic

Journal ArticleDOI

Intuitive semantics for first-degree entailments and ‘coupled trees’

TL;DR: In this paper, the authors propose a tableau-based approach to show that an argument A may entail B because of some feature of A alone, irrespective of B, and vice versa.
Journal ArticleDOI

Bilattices and the semantics of logic programming

TL;DR: Bilattices are a family of truth-value spaces that allow elegantly for missing or conflicting information, and a fixed-point semantics is developed for logic programming, allowing any bilattice as the space of truth values.
MonographDOI

An Introduction to Non-Classical Logic: From If to Is

TL;DR: In this article, the authors present a survey of modal logics with gaps, gluts, and worlds in the context of Propositional Logic, including many valued modal logic and many-valued logic with first degree entailment.