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论文类型：会议论文

发表时间：2008-10-18

收录刊物：EI、CPCI-S、Scopus

卷号：1

页面范围：448-+

关键字：rough set; category; topos; middle object; weak topos

摘要：This paper shall study theory of rough sets from the view of the category theory and topos theory. A category RSC of I-rough sets is presented. Topos properties of the category RSC are studied. It is proved that the category RSC satisfies all properties of a topos except one, for it has no subobject classifier It is pointed that although the category RSC is not a topos, RSC has a middle object and consequently RSC is a weak topos. By the use of weak topos RSC, the operations of I-rough sets are naturally described.