Funding for this research was provided by:
National Science Foundation (DMS-1521830)
U.S. Department of Energy (DE-FC02-13ER26134/DE-SC0009409)
National Science Foundation (DMS-1454939, DMS-1107444)
National Science Foundation (DMS-1107465)
Article History
Received: 27 February 2018
Accepted: 18 September 2018
First Online: 25 October 2018