A Comparison of the Static and the Disjunctive Well-Founded Semantics and its Implementation.
Stefan Brass, Jürgen Dix, Ilkka Niemelä, Teodor C. Przymusiński · 1998
In recent years, much work was devoted to the study of theoretical foundations of Disjunctive Logic Programs and Disjunctive Deductive Databases. While the semantics of non-disjunctive programs is fairly well understood the declarative and computational foundations of disjunctive programming proved to be much more elusive and difficult. Recently, two new and very promising semantics have been proposed for the class of disjunctive logic programs. Both of them extend the wellfounded semantics of normal programs. The first one is the static semantics proposed by Przymusinski and the other is the disjunctive wellfounded semantics proposed by Brass and Dix. Although the two semantics are based on very different ideas, we show in this paper that they turn out to be very closely related. In fact, we show that it is possible to restrict the underlying language of STATIC to get D-WFS. We also show how to use this characterization for an implementation based a circumscriptive theorem prover.