Affiliations: [a] College of Mathematics, Southwest Jiaotong University, Chengdu, Sichuan 610031, China. keyunqin@263.net | [b] Center for Radio Administration and Technology Development, Xihua University, Chengdu, Sichuan 610039, China
Correspondence:
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Address for correspondence: College of Mathematics, Southwest Jiaotong University, Chengdu, Sichuan 610031, China
Note: [†] This work has been supported by the National Natural Science Foundation of China (Grant No. 61473239, 61175044, 61372187), the Fundamental Research Funds for the Central Universities of China (Grant No. 2682014ZT28) and the Open Research Fund of Key Laboratory of Xihua University (szjj2014-052).
Abstract: Rough set approach for knowledge discovery in incomplete information systems has been extensively studied. This paper conduct a further study of valued tolerance relation based rough approximations. We make an analysis of the existing rough approximabilities and propose a new approach for lower (upper) approximability, which is a generalization of Pawlak approximation operators for complete information system. The approach has also been generalized to fuzzy cases. Some basic properties of the approximation operators are examined.
