Affiliation: | 1. School of Mathematics and Statistics, Qinghai Normal University, Xining, Qinghai 810008, China;2. Academy of Plateau Science and Sustainability, Xining, Qinghai 810008, China;3. College of Science, China Jiliang University, Hangzhou 310018, China;4. UPS of America, Inc. Atlanta, GA, USA;5. Technische Universität Bergakademie Freiberg, Institut für Diskrete Mathematik und Algebra, 09596 Freiberg, Germany |