Amer Amikhteh; Lotfollah Nabavi
Abstract
The uninorm logic UL is a fuzzy, substructural and semi-relevant logic. The Gentzen-style system for UL is obtained by removing the contraction rules and weakening from the Gentzen-style system of Godel fuzzy logic. The UL lacks "excluded middle", "positive paradox" and "negative paradox". The truth ...
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The uninorm logic UL is a fuzzy, substructural and semi-relevant logic. The Gentzen-style system for UL is obtained by removing the contraction rules and weakening from the Gentzen-style system of Godel fuzzy logic. The UL lacks "excluded middle", "positive paradox" and "negative paradox". The truth function of uninorm is a relevance weakening of the t-norm function. In this article, we introduce the new logic ULΔ. ULΔ is obtained by adding Δ to UL. ULΔ, an expansion of classical logic, is a normal semilinear modal logic; i.e. it is strongly sound and complete w.r.t. a linearly ordered algebra. And with the theorem of (p→q)∨Δ(q→p) it is distinguished from other standard systems of modal logic. Δφ is intuitively interpreted as "true that φ" or more precisely "classically true that φ". In this paper, we introduce the semi-classical logic ULΔ with four approaches, axiomatizations, hypersequent calculi, algebraic semantics and standard semantics. metatheorems we are considering include Delta deduction, strong soundness, strong standard completeness and definability of classical logic.
