About author:YAN Jie-sheng(1964- ), male, native of Shangqiu, Henan, an assistant professor of Shangqiu Vocational and Technical College, M.S.D., engages in finite group; YANG Li-hua(1979- ), female, native of Zhengzhou, Henan, a lecturer of Zhongyuan University of Technology, M.S.D., engages in finite group.