Affiliation: | 1. College of Mathematics and System Sciences, Xinjiang University, Urumqi, Xinjiang 830046, PR China;2. School of Mathematics and Big Data, Huizhou University, Guangdong, PR China;3. School of Mathematics and Statistics, Jiangsu Normal University, Xuzhou, Jiangsu, 221116, China;4. Department of Mathematics, West Virginia University, Morgantown, WV 26506, USA |