1. The investigation of covering rough sets by Boolean matrices.
- Author
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Ma, Liwen
- Subjects
- *
ROUGH sets , *SET theory , *BOOLEAN matrices , *APPROXIMATION theory , *ALGORITHMS - Abstract
In covering rough set theory, the basic problem is the calculation of lower and upper approximations for subsets of a covering approximation space. For a covering approximation space with a large cardinal, using definitions to calculate approximations would be tedious and complicated. So it is important to investigate matrix methods by which calculations will become algorithmic and can be easily implemented by computers. Since the covering in a covering approximation space can be represented by a Boolean matrix, every covering rough approximation operator must be closely related to this matrix. In this paper, we investigated 32 pairs of neighborhood-based dual lower and upper approximation operators and successfully obtained all the matrix representations of them. Some examples were presented in the manuscript to illustrate how to use matrix methods to compute lower and upper approximations and examples were also given to solve the inverse problem, i.e., finding all the subsets whose lower or upper approximation is a given subset. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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