Pointwise Circumscription: Preliminary Report

Abstract

Circumscription is the minimization of predicates subject to restrictions expressed by predicate formulas. We propose a modified notion of circumscription so that, instead of being a single minimality condition, it becomes an “infinite conjun(*tion ” of “local ” minimality condi-tions; each of these conditions expresses the impbssibility of changing the value of a predicate from true to f&e at one point. We argucl that this “pointwise ” circumscrip-tion is conceptually simpler than the traditional “global” approach and, at the same time, leads to generalizations with the atl&tionaJ. flexibility needed in applications to the theory of commonsense reasoning. 1.