*APPROXIMATION theory, *ROUGH sets, *AXIOMATIC set theory, *TOPOLOGY, *COMPUTER science, *COMPUTER systems
Abstract
Abstract: This paper studies covering-based rough sets by means of characteristic functions of sets. We consider covering-based rough sets from both constructive and axiomatic approaches. The relationship among four types of covering-based rough sets is discussed. We also outline the topologies induced by different covering approximations. [Copyright &y& Elsevier]