A Computation of Core for the Information System

A lot of methods of attributes reduction are based on the core of the attributes, then using a certain intelligent algorithm to get the attributes whose number is the minimum. This paper presents a new computation of core for the information system: first, the relationship between core attribute and indispensable attribute is described, meanwhile, a necessary and sufficient condition proved by the theory is presented to judge if a certain attribute is core or not; second, a detail computation of core is designed and computational complexity is analyzed; finally, the validity of this approach is proved by comparing method of the initial definition and the method in this paper.