Based on the least absolute deviation estimation, local linear least absolute deviation algorithm is derived. The efectiveness and robustness of our method are verifed by simulation compared with the least absolute deviation kernel algorithm and local linear least squares algorithm. The model can also reduce the boundary efect.

Suppose R is a principal ideal ring,GL(n,R) is a linear group over R,H_r is a subgroup of GL(n,R),then all the overgroups of H_r in GL(n,R) are determined,for the case n≥3.

We discussed the application of mathematics software in teaching,and made a comparative analysis of some solutions for linear programming problem.