Transforming Abductive Logic Programs to Disjunctive Programs

A new fixpoint semantics for abductive logic programs is provided, in which the generalized stable models of an abductive program are characterized as the fixpoint of a disjunctive program obtained by a suitable program transformation. In the transformation, both negative hypotheses through negation as failure and positive hypotheses from the abducibles are dealt with uniformly. This characterization allows us to have a parallel bottomup model generation procedure for computing abductive explanations from arbitrary (range-restricted and function-free) general, extended, and disjunctive programs with integrity constraints.