Affiliation: | 1.School of Mathematics and Statistics, Hainan Normal University, Haikou 571158, China;2.Key Laboratory of Data Science and Smart Education, Ministry of Education, Hainan Normal University, Haikou 571158, China;3.School of Science, Beijing Information Science and Technology University, Beijing 100192, China;4.Department of Mathematics, Shanghai University, Shanghai 200444, China;5.Department of Mathematics, North Carolina State University, Raleigh, NC 27695, USA |