| The paper is mainly about the linear nonstandard singular perturbation system of how to decompose it into slow subsystem and fast subsystem.The related differential algebraic system is simplified through a coordinate transformation in chapter two.Then, we successfully decompose the system of index 2, and obtain a procedure which can be programming with no difficulty.After that, we tried to decompose the system of index 3 in the same way as the index 2. To take advantage of the index 2, it takes effort to reduce index 3 to index 2,and we acquire some conclusion as lemma 4.1 which can reduce the index k and index k+1 after generalization. And for index n, we can get the similar conclusion by mathematical induction.For index n, we get main result all in chapter 5 and chapter 6. In chapter 6 we give out a approximated estimation between two subsystem and singular perturbation system of index n. |