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We present a framework for expressing bottom-up algorithms to compute the well-founded model of non-disjunctive logic programs. Our method is based on the notion of conditional facts and elementary program transformations studied by Brass and Dix in (Brass & Dix, 1994; Brass & Dix, 1999) for disjunctive programs. However, even if we restrict their framework(More)
Our aim in this article is to supplement the set of strong properties introduced in the preceding article ([Dix94]) with a set of weak principles in order to characterize semantics of logic programs. In [Dix94] we introduced our point of view: we observed that all semantics induce in a natural way a sceptical non-monotonic entailment relation SEM scept. We(More)
Our aim in this article is to present a method for classifying and characterizing the various different semantics of logic programs with negation that have been considered in the last years. Instead of appealing to more or less questionable intuitions, we take a more structural view: our starting point is the observation that all semantics induce in a(More)
We present a new and general approach for deening, understanding, and computing logic programming semantics. We consider disjunctive programs for generality, but our results are still interesting if specialized to normal programs. Our framework consists of two parts: (1) a semantical, where semantics are deened in an abstract way as the weakest semantics(More)
44 played a dominant role in Przymusinski's versions of WFS and ST N. The results of Section 4 underline the very strong relationship of NMR-semantics with nonmonotonic logics. We have also tried (in Section 5) to use another branch of nonmonotonic logics in order to get a classiication of the various diierent semantics: the approach, pioneered by Makinson,(More)
Recently, Brass and Dix showed (Journal of Automated Reasoning 20(1), 1998) that the wellfounded semantics WFS can be deened as a connuent calculus of transformation rules. This lead not only to a simple extension to disjunctive programs (Journal of Logic Programming 38(3), 1999), but also to a new computation of the wellfounded semantics which is linear(More)