Data mining attracts great attention in information industry. The major reason is that large amount of existing data may be used widely, and it is urgently necessary to convert these data into useful information and knowledge.
Rough set theory is very important for artificial intelligence and cognitive science. It is emphasized and highly appraised by Zadeh, the founder of fuzzy mathematics, since it appeared. And also it is listed into the basic theory of soft computing which Zadeh newly advocated...