A new computation model for rough set theory based on database systems

We propose a new computation model for rough set theory using relational algebra operations in this paper. We present the necessary and sufficient conditions on data tables under which an attribute is a core attribute and those under which a subset of condition attributes is a reduct, respectively. With this model, two algorithms for core attributes computation and reduct generation axe suggested. The correctness of both algorithms is proved and their time complexity is analyzed. Since relational algebra operations have been efficiently implemented in most widely-used database systems, the algorithms presented can be extensively applied to these database systems and adapted to a wide range of real-life applications with very large data sets.