Funding for this research was provided by:
Engineering and Physical Sciences Research Council (EP/E035027/1, EP/L015811/1)
National Science Foundation (DMS-1401490, DMS-1764278)
City University of Hong Kong (7200429(MA))
Royal Society London (Royal Society–Wolfson Research Merit Award)
Research Grants Council of the HKSAR, China (CityU 21305215, CityU 11332916)
Research Grants Council of the HKSAR, China (CityU 11304817, CityU 11304818)
National Science Foundation (DMS-11012600000-0001-5146-3839)
Article History
Received: 9 November 2019
Accepted: 8 April 2020
First Online: 12 June 2020
Compliance with ethical standards
:
: The authors declare that they have no conflict of interest.