We propose a framework which extends Antitonic Logic Programs [2] to an arbitrary complete bilattice of truth-values, where belief and doubt are explicitly represented. Based on Fitting’s
ideas, this framework allows a precise definition of important operators found in logic programming such as explicit negation
and the default negation. In particular, it leads to a natural integration of explicit negation with the default negation
through the coherence principle [19]. According to this principle, the explicit negation entails the default negation. We then define Coherent Answer Sets, and
the Paraconsistent Well-founded Model semantics, generalizing paraconsistent semantics for logic programs (for instance, WFSX
p [4]). Our framework is an extension of important classes of Antitonic Logic Programs, and is general enough to capture Probabilistic
Deductive Databases, Possibilistic Logic Programming, Hybrid Probabilistic Logic Programs, and Fuzzy Logic Programming. Thus,
we have a powerful mathematical formalism for dealing with default reasoning, paraconsistency, and uncertainty.
João Alcântara is a PhD student supported by CAPES - Brasília, Brazil. The authors also thank the TARDE and FLUX projects,
sponsored by MCT - Portugal.