作者机构:[1]College of Mathematics, Guangxi Normal University, Guilin 541004, China, [2]College of Applied Sciences, Beijing University of Technology, Beijing 100124, China, [3]Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing 100190, China
相关基金:This research was supported by the National Natural Science Foundation of China under Grant Nos. 10661003, 10371126, the Guangxi Science Foundation under Grant No. 0832102 and the Doctor Foundation of Guangxi Normal University.