Affiliation: | 1. Department of Mathematics Education and the RINS, Gyeongsang National University, Chinju 660-701, Republic of Korea;2. Department of Mathematics, Gyeongsang National University, Chinju 660-701, Republic of Korea;1. School of Mathematics and Statistics, Chongqing Technology and Bussiness University, Chongqing 400067, China;2. College of Mathematics, Sichuan University, Chengdu 610064, China;3. School of Mathematics and Statistics, Central South University, Changsha 410083, China |