The expressive power of circumscription

摘要

Circumscription is a form of nonmonotonic reasoning, introduced by McCarthy (1997) as a way of characterizing defaults using second order logic. The consequences of circumscription are those formulas true in the minimal models under a pre-order on models. In the case of domain circumscription the pre-order was the sub-model relation. Formula circumscription (McCarthy, 1980, 1986) is characterized by minimizing a set of formulas—one model is preferred to another model when the extensions of the minimized formulas in the first are subsets of the extensions in the second.