| Affiliation: | 1. Department of Mathematics, National University of Singapore, Kent Ridge, Singapore 119260, Republic of Singapore;2. Division of Mathematical Sciences, School of Physical & Mathematical Sciences, Nanyang Technological University, Singapore 637371, Republic of Singapore;1. Università di Pisa, Dipartimento di Matematica, Largo B. Pontecorvo 5, 56127 Pisa, Italy;2. Università della Calabria, Dipartimento di Matematica e Informatica, Ponte P. Bucci, Cubo 30B, 87036 Rende (CS), Italy;1. Univ. de Caen Normandie, UMR CNRS 6139 LMNO & IREM, 14000 Caen, France;2. Nabeul, Tunisia;1. School of Mathematics and Statistics, Qingdao University, Qingdao 266071, PR China;2. Institute of Applied Mathematics of Shandong, Qingdao University, Qingdao 266071, PR China;3. School of Science, Linyi University, Linyi 276005, PR China |
