作者机构:[1]School of Mathematical Sciences, Peking University, Beijing 100871, China., [2]Department of Mathematics, Brigham Young University, Provo, UT 84602, USA., [3]Department of Mathematics, University of Michigan Ann Arbor, MI 48105, USA.
相关基金:This work was supported by the Natural Science Foundation (Nos. DMS-1564502, DMS-1405245, DMS- 1564457), the National Natural Science Foundation of China (Nos. 11325101, 11271028) and the Ph.D. Programs Foundation of Ministry of Education of China (No. 20120001110060).