Combining Circumscription and Modal Logic

This paper discusses the logic LKM which extends circumscription into an epistemic domain. This extension will allow us to define circumscription of predicates that appear within the context of a modal operator. In fact, LKM can be seen as a method of extending any first-order nonmonotonic logic whose semantic definition is based on a partial-order among models, into a new nonmonotonic logic defined for a modal language, whose modal operator (K) follows an undedying S5 or weak-S5 semantics. One interesting use of this nonmonotonic logic is to model nonmonotonic aspects of the communication between agents.