A (propositional) logic L is paraconsistent with respect to a negation connective if P; P 6`L Q in case P and Q are two distinct atomic variables. Intuitively (and practically) the logic(s) we use should be paraconsistent (with respect to any unary connective!) on the ground of relevance: why should a \contradiction" concerning P imply something completely unrelated? Nevertheless, the most know...

Chu spaces, which derive from the Chu construct of ∗-autonomous categories, can be used to represent most mathematical structures. Moreover, the logic of Chu spaces is linear logic. Most efforts to incorporate fuzzy set theory into the realm of linear logic are based on the assumption that fuzzy and linear negation are identical operations. We propose an incorporation based on the opposite assu...

Paraconsistent logics are specially tailored to deal with inconsistency, while fuzzy logics primarily deal with graded truth and vagueness. Aiming to find logics that can handle inconsistency and graded truth at once, in this paper we explore the notion of paraconsistent fuzzy logic. We show that degree-preserving fuzzy logics have paraconsistency features and study them as logics of formal inc...

Abstract: In this paper, the theory of T-norm and T-conorrn is reviewed and the T-norm, T-conorm and negation function are defined as a set of T-operators. Some typical T-operators and their mathematical properties are presented. Finally, the T-operators are extended to the conventional fuzzy reasoning methods which are based on the MIN and MAX operators. This extended fuzzy reasoning provides ...

The law of contraposition with respect to a negation (usually strong) is one of the most studied properties in the theory of fuzzy implication functions. We already know some methods for modifying an implication with the aim that the new implication satisfies this property, these methods are called contrapositivisation. In this paper we present two new methods of contrapositivisation with respe...

There are several ways to extend the classical logical connectives for fuzzy truth degrees, in such a way that their behavior for the values 0 and 1 work exactly as in the classical one. For each extension of logical connectives the formulas which are always true (the tautologies) changes. In this paper we will provide a fuzzy interpretation for the usual connectives (conjunction, disjunction, ...

Using Generalized Modus Ponens reasoning, we examine the values of the inferred conclusion by using Fodor's implication in order to interpret a fuzzy if-then rule with a single input single output and the tnorm ( ) ( )( ) ( xy y x max y , x t ) λ λ − − + + = 1 1 , 1 − ≥ λ , for composition operation. This t-norm is important to use because for 1 − = λ and 0 = λ it gives the commonly used t-norm...

In this paper, we introduce the tractable pf -EL logic, a paraconsistent version of the fuzzy logic f -EL. Within pf -EL, it is possible to tolerate contradictions under incomplete and vague knowledge. pf -EL extends the f -EL language with a paraconsistent negation in order to represent contradictions. This paraconsistent negation is defined under Belnap’s bilattices. It is important to observ...

This paper is directed towards an infrastructure for handling both uncertainty and vagueness in the Rules, Logic, and Proof layers of the Semantic Web. More concretely, we present probabilistic fuzzy description logic programs, which combine fuzzy description logics, fuzzy logic programs (with stratified nonmonotonic negation), and probabilistic uncertainty in a uniform framework for the Semant...

Understanding natural languages is a great challenge of computer science. One of the issues that must be tackled is the interpretation of linguistic negations. In this work, we present the problem and propose some solutions grounded in fuzzy sets theory.