Funding for this research was provided by:
Department of Science and Technology and National Research Foundation, Republic of South Africa Center of Excellence in Mathematical and Statistical Sciences (DST-NRF COE-MaSS) Doctoral Bursary (BA-2019-067)
National Research Foundation (NRF) of South Africa (119903)
International Mathematical Union Breakout Graduate Fellowship (IMU-BGF-2019-10)
Article History
Received: 3 May 2019
Revised: 16 October 2019
Accepted: 14 November 2019
First Online: 28 November 2019