Institution: | 1. School of Science, East China Jiaotong University, Nanchang , Jiangxi, Postal code 330013, PR China;2. School of Mathematics, South China Normal University, Guangzhou, Guangdong, Postal code 510631, PR China;3. School of Mathematics and Computer Science, Guizhou Normal University, Guiyang, Guizhou, Postal code 550001, PR China |