A Fixpoint Characterization of Abductive Logic Programs

Katsumi Inoue and Chiaki Sakama

Journal of Logic Programming 27:107-136, North-Holland, 1996.


A new fixpoint semantics for abductive logic programs is provided, in which the belief 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. The result is further generalized to a fixpoint semantics for abductive extended disjunctive programs. These characterizations allow us to have a parallel bottom-up model generation procedure for computing abductive explanations from any (range-restricted and function-free) normal, extended, and disjunctive programs with integrity constraints.

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