A rough logic based on incomplete information and its application

Abstract This paper discusses a new rough logic based on incomplete information. Originally rough logic was constructed upon knowledge systems of complete information. In this paper, we consider incomplete knowledge representation systems in which information functions are nondeterministic. After modifying the usual definitions of upper and lower approximation operations in rough logic, we examine some properties of these operations. Also, we consider a relationship of the proposed logic to KTB modal logic. Then, we remark about an application of incomplete information systems to decision logic.