| Affiliation: | 1. Department of Mathematics, Shanghai University, Shanghai 200444, PR China;2. Department of Mathematics, Bohai University, Jinzhou of Liaoning Province 121000, PR China;3. Department of Mathematics, Tianjin University, Tianjin 300072, PR China;1. Korteweg-de Vries Institute for Mathematics, University of Amsterdam, P.O. Box 94248, 1090 GE Amsterdam, The Netherlands;2. Instituto Nacional de Matematica Pura e Aplicada, Estrada Dona Castorina 110, 22460-320 Rio de Janeiro, Brazil;1. School of Mathematical Science, University of Science and Technology of China, Hefei 230026, P. R. China;2. Wu Wen-Tsun Key Laboratory of Mathematics, USTC, Chinese Academy of Sciences, P. R. China |
