A Comparison of the Static andthe Disjunctive Well -

In recent years, much work was devoted to the study of theoretical foundations of Disjunctive Logic Programs and Disjunctive De-ductive 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 diicult. Quite recently, two new and very promising semantics have been proposed for the class of disjunctive logic programs. Both of them extend the well-founded semantics of normal programs. The rst one is the static semantics proposed by Przymusinski and the other is the D-WFS semantics proposed by Brass and Dix. Although the two semantics are based on very diierent 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 eecient implementation based on a prover for computing minimal models for positive disjunctive programs.