UNFOLDING THE WELL–FOUNDED SEMANTICS

Matthias Wendt

   We study the fixpoint completion for logic programs, proposed by Dung and Kanchanasut. The fixpoint completion is a progam transformation – it performs a kind of unfolding of recursion through positive atoms in the clauses of a program – that was shown to preserve the semantics of a program in a certain sense. We generalize the results from Dung and Kanchanasut in some ways and show how the handling of negation is transformed by the fixpoint completion. We thereby obtain a more clarified view of both the fixpoint completion itself and the relationship between well-founded and Fitting semantics for logic programs.

Keywords: logic programming, nonmonotonic reasoning, unfolding, well-founded semantics

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