Affiliation: | 1. School of Mathematics and Information Sciences, Weifang University, Weifang 261061, PR China;2. Department of Mathematics, Shanghai University, 99 Shangda Road, Shanghai 200444, PR China;3. Division of Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore;4. Department of Applied Mathematics, Shanghai Finance University, Shanghai 201209, PR China |