Constructive methods of rough approximation operators and multigranulation rough sets

摘要

Four kinds of constructive methods of rough approximation operators from existing rough sets are established, and the important conclusion is obtained: some rough sets are essentially direct applications of these constructive methods. Moreover, the new notions of non-dual multigranulation rough sets and hybrid multigranulation rough sets are introduced, and some properties ate investigated. (C) 2015 Elsevier B.V. All rights reserved.