For inference purposes in both classical and fuzzy logic, neither the information itself should be contradictory, nor should any of the items of available information contradict each other. In order to avoid these troubles in fuzzy logic, a study about contradiction was initiated by Trillas et al. in [5] and [6]. They introduced the concepts of both self-contradictory fuzzy set and contradictio...

Recently several authors have stressed and illustrated the importance of including a second kind of negation (explicit negation) in logic programs besides \negation as failure", and its use in deductive databases, knowledge representation, and nonmonotonic reasoning. By introducing explicit negation into logic programs contradiction may appear. In this work we present two approaches for dealing...

The problems of the meaning and function of negation are disentangled from ontological issues with which they have been long entangled. TIle question of the function of negation is the crucial issue separating relevant and paraconsistent logics from classical theories. The function is illuminated by considering the inferential role of contradictions, contradiction being parasitic on negation. T...

After observing a contradiction between the 'official' ideology defined by open-source licenses and the actual behavior of hackers, we examine the actual customs which regulate the ownership and control of open-source software. We discover that they imply an underlying theory of property rights homologous to the Lockean theory of land tenure. We relate that to an analysis of the hacker culture ...

1. Genuine worlds, ersatz worlds David Lewis has argued that impossible worlds are nonsense. 1 If there were such worlds, one would have to distinguish between the truths about their contradictory goings-on and contradictory falsehoods about them. One would have to distinguish between, say, the alleged truth (1a) In so-and-so world pigs can fly; and in that world pigs also cannot fly, and the c...

Some aspects of the result of applying unit resolution on a cnf formula can be formalized as functions with domain a set of partial truth assignments. We are interested in two ways for computing such functions, depending on whether the result is the production of the empty clause or the assignment of a variable with a given truth value. We show that these two models can compute the same functio...