A Generalization of Circumscription

In this paper we firstly extend McCarthy s circumscription to modal logics.Similar to circumscribing predicates,we circumscribe the critical modal operator(the operator to be minimized)in a formula.The modal formulation of circumscription is completely characterized by the minimal model such as the predicate circumscription,The circumscriptive ignorance of the agent s self-knowledge by circumscribing knowledge operator is then illustrated.We further suggest that the merit of circumscription is basic for non…