Rule extracting method based upon relative decision conditions

The concept of relative decision is put forward and the method for finding absolute reduction decision rule through combining rules of relative decisional condition sets is given in this paper. In the process of decision table reduction, the discernibility matrix between decision category should be created in order to decide the relative decision conditions which are conjoined to find the decision conditions of all the decision classes. In addition, the method for finding all minimal relative condition clusters based upon relative decision condition is also introduced. Both of the methods can be used to finding all the minimal decision sets in decision table.