A modal nonmonotonic logic

A modal nonmonotonic logic is presented based on an experiential modal semantics on typicality and exception. The syntactic and semantics of modal nonmonotonic logic are provided and the completeness theorem and the theorems relating it to major nonmonotonic logics are proved. It directly formalizes the intuition of nonmonotonic reasoning. Among other things, it provides us a first-order extension of default logic and autoepistemic logic, and simultaneously has the capability of circumscription to infer universal statement. It has important applications in logic programming and deductive data base. As a result, it provides a uniform basis for various nonmonotonic logics, from which the correspondent relationship among major nonmonotonic logics can coincide.