In this paper, we use a 'normality operator' in order to generate logics of formal inconsistency and logics of formal undeterminedness from any subclassical many-valued logic that enjoys a truth-functional semantics. Normality operators express, in any many-valued logic, that a given formula has a classical truth value. In the first part of the paper we provide some setup and focus on many-valued logics that satisfy some (or all) of the three properties, namely subclassicality and two properties that we call fixed-point negation property and conservativeness. In the second part of the paper, we introduce normality operators and explore their formal behaviour. In the third and final part of the paper, we establish a number of classical recapture results for systems of formal inconsistency and formal undeterminedness that satisfy some or all the properties above. These are the main formal results of the paper. Also, we illustrate concrete cases of recapture by discussing the logics K⊛3, LP⊛, Kw⊛3, PWK⊛ and Efde⊛, that are in turn extensions of K3, LP, Kw3, PWK and Efde, respectively.
Ciuni, R., Carrara, M. (2020). Normality operators and classical recapture in many-valued logic. LOGIC JOURNAL OF THE IGPL, 28(5), 657-683 [10.1093/jigpal/jzy055].
Normality operators and classical recapture in many-valued logic
Ciuni R.;
2020-01-01
Abstract
In this paper, we use a 'normality operator' in order to generate logics of formal inconsistency and logics of formal undeterminedness from any subclassical many-valued logic that enjoys a truth-functional semantics. Normality operators express, in any many-valued logic, that a given formula has a classical truth value. In the first part of the paper we provide some setup and focus on many-valued logics that satisfy some (or all) of the three properties, namely subclassicality and two properties that we call fixed-point negation property and conservativeness. In the second part of the paper, we introduce normality operators and explore their formal behaviour. In the third and final part of the paper, we establish a number of classical recapture results for systems of formal inconsistency and formal undeterminedness that satisfy some or all the properties above. These are the main formal results of the paper. Also, we illustrate concrete cases of recapture by discussing the logics K⊛3, LP⊛, Kw⊛3, PWK⊛ and Efde⊛, that are in turn extensions of K3, LP, Kw3, PWK and Efde, respectively.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.