#
Negation in Disjunctive Logic Programs

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Chiaki Sakama and Katsumi Inoue

* Proceedings of the 10th International Conference on
Logic Programming (ICLP'93), pp. 703-719, MIT Press, 1993.
*
## Abstract

In this paper, we study inferring negation from disjunctive logic
programs.
First, we consider extensions of the GCWA and the WGCWA for general
disjunctive programs based upon the stable model semantics.
We define new rules, the GCWA~ and the WGCWA~, which
are natural extensions of the GCWA and the WGCWA.
Second, we introduce a new semantics called the *possible world
semantics* for general disjunctive programs, which was
initially introduced in [Sakama 89] for positive disjunctive programs.
The *possible world assumption (PWA)* infers negation under the
possible world semantics, which lies between the GCWA and the WGCWA in
positive disjunctive programs. The PWA is also extended to the PWA~
for general disjunctive programs. Then it is shown that the PWA~
provides a powerful and the most careful negative inference compared with
the GCWA~ and the WGCWA~. We also present a bottom-up
model generation proof procedure to compute each negation in general
disjunctive programs.

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