Aus International Center for Computational Logic
von Walter Forkel
Circumscription is one of the classic formalisms for introducing non-monotonicity in a logic. In this talk, we show that the current version of circumscription in certain cases does not allow to draw conclusions that would be expected intuitively. We analyze the cases in which that happens and introduce a novel definition of circumscription that subsumes the original circumscription, and behaves as intuitively expected. We show that the new formulation has useful properties, in particular that it reduces to standard first-order logic in certain setups.