Intuitionistic Implication and Logics of Formal Inconsistency

Logics of Formal Inconsistency (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>L</mi><mi>F</mi><mi>I</mi></mrow></semantics></math></inline-for...

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Main Author: Janusz Ciuciura
Format: Article
Language:English
Published: MDPI AG 2024-10-01
Series:Axioms
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Online Access:https://www.mdpi.com/2075-1680/13/11/738
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author Janusz Ciuciura
author_facet Janusz Ciuciura
author_sort Janusz Ciuciura
collection DOAJ
description Logics of Formal Inconsistency (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>L</mi><mi>F</mi><mi>I</mi></mrow></semantics></math></inline-formula> for short) are a class of paraconsistent logics that validate the principle of gentle explosion, meaning that any formula can be derived from the set of formulas: <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>∘</mo><mi>α</mi></mrow></semantics></math></inline-formula>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>α</mi></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>∼</mo><mi>α</mi></mrow></semantics></math></inline-formula>. A unique feature of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>L</mi><mi>F</mi><mi>I</mi></mrow></semantics></math></inline-formula> is the use of the symbol ‘∘’ to represent notions of consistency at the object-language level. These logics are simple in essence, built upon all the axiom schemas of positive classical logic, axioms for negation and the so-called ‘consistency operator’ ∘, with the only inference rule being detachment. In this paper, we propose an alternative foundation for <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>L</mi><mi>F</mi><mi>I</mi></mrow></semantics></math></inline-formula>, which is the positive fragment of intuitionistic propositional logic. We present bi-valuational ‘Loparić-like’ semantics for the resulting logics and discuss their potential extensions.
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spelling doaj-art-5e7fa1f00dcd457397f0e6ff88412d0d2025-08-20T02:26:45ZengMDPI AGAxioms2075-16802024-10-01131173810.3390/axioms13110738Intuitionistic Implication and Logics of Formal InconsistencyJanusz Ciuciura0Department of Logic and Methodology of Science, Institute of Philosophy, University of Łódź, Lindleya 3/5, 90-131 Łódź, PolandLogics of Formal Inconsistency (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>L</mi><mi>F</mi><mi>I</mi></mrow></semantics></math></inline-formula> for short) are a class of paraconsistent logics that validate the principle of gentle explosion, meaning that any formula can be derived from the set of formulas: <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>∘</mo><mi>α</mi></mrow></semantics></math></inline-formula>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>α</mi></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>∼</mo><mi>α</mi></mrow></semantics></math></inline-formula>. A unique feature of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>L</mi><mi>F</mi><mi>I</mi></mrow></semantics></math></inline-formula> is the use of the symbol ‘∘’ to represent notions of consistency at the object-language level. These logics are simple in essence, built upon all the axiom schemas of positive classical logic, axioms for negation and the so-called ‘consistency operator’ ∘, with the only inference rule being detachment. In this paper, we propose an alternative foundation for <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>L</mi><mi>F</mi><mi>I</mi></mrow></semantics></math></inline-formula>, which is the positive fragment of intuitionistic propositional logic. We present bi-valuational ‘Loparić-like’ semantics for the resulting logics and discuss their potential extensions.https://www.mdpi.com/2075-1680/13/11/738paraconsistent logicda Costa’s logiclogics of formal inconsistencyconsistency operatorintuitionistic implication
spellingShingle Janusz Ciuciura
Intuitionistic Implication and Logics of Formal Inconsistency
Axioms
paraconsistent logic
da Costa’s logic
logics of formal inconsistency
consistency operator
intuitionistic implication
title Intuitionistic Implication and Logics of Formal Inconsistency
title_full Intuitionistic Implication and Logics of Formal Inconsistency
title_fullStr Intuitionistic Implication and Logics of Formal Inconsistency
title_full_unstemmed Intuitionistic Implication and Logics of Formal Inconsistency
title_short Intuitionistic Implication and Logics of Formal Inconsistency
title_sort intuitionistic implication and logics of formal inconsistency
topic paraconsistent logic
da Costa’s logic
logics of formal inconsistency
consistency operator
intuitionistic implication
url https://www.mdpi.com/2075-1680/13/11/738
work_keys_str_mv AT januszciuciura intuitionisticimplicationandlogicsofformalinconsistency