Institution: | (1) Department of Mathematics and Statistics, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA, US;(2) School of Mathematics, University of South Australia, The Levels, SA 5095, Australia (e-mail: jerzy.filar@unisa.edu.au), AU;(3) Institute of Applied Mathematics, Academia Sinica, Beijing 100080, PR China (e-mail: kliu@midwest.com.cn), CN |