Rough Set Approximations in Formal Concept Analysis and Knowledge Spaces

Feifei Xu, Yiyu Yao, Duoqian Miao

Abstract: This paper proposes a generalized definition of rough set approximations, based on a subsystem of subsets of a universe. The subsystem is not assumed to be closed under set complement, union and intersection. The lower or upper approximation is no longer one set but composed of several sets. As special cases, approximations in formal concept analysis and knowledge spaces are examined. The results provide a better understanding of rough set approximations.