Acquiring optimal relative reduction by descending approach to core of attribute from original set of conditional attribute and combining with operator.
以原始条件属性集为起点并结合算子，通过向属性核的递减式逼近，得到属性的最小相对约简。
2
The reduction speed is increasing along with the concentration of N and P in water, whereas the removal rate of N and P is descending.