Liu, Chun
Funding for this research was provided by:
National Science Foundation (DMS-1714401, DMS-1412005)
National Natural Science Foundation of China (No. 11631011)
Article History
Received: 3 November 2017
Accepted: 11 January 2019
First Online: 31 January 2019
Compliance with Ethical Standards
:
: C. Liu is partially supported byNSF grantsDMS-1714401, DMS-1412005. H. Wu is partially supported by NNSFC grant No. 11631011 and the Shanghai Center for Mathematical Sciences at Fudan University.
: The authors declare that they have no conflict of interest.