Abstract: It is well-known that the monotonicity plays an important role in attribute reduction of classical rough set.However,such property does not always hold in some generalization models,and quantitative rough set is a typical example.From this point of view,the definition of lower approximate monotonicity attribute reduction was presented in quantitative rough set model,and the heuristic approach was also given to compute the reduct.The experiment results show that compared with lower approximate preservation reduct,the lower approximate monotonicity can not only save the time consuming,but also increase the certainties which are expressed by positive and negative regions,and decrease the uncertainty coming from boundary region.

Key words: Monotonicity,Lower approximate preservation,Lower approximate monotonicity,Rough set