Research on Discernibility Matrix Based on Positive Region Reduction of the Decision Table

Using the discernibility matrix,it is easy to calculate all attribute reduction of decision table.The characteristic of some created discernibility matrix in the decision table is analyzed and an improved discernibility matrix is presented.The partition U/C or positive region needs not to be calculated and the discernibility matrix can be constructed directly from the decision table.Several theorems of improved discernibility matrix are gained.Based on the above results,an algorithm using the improved discernibility matrix to calculate positive region,core,minimal reduction and all reduction of the decision table is given.Theoretical analysis and an example show that the new algorithm can have the same reduction as the algorithm given in reference ,but it requires less computational effort.