Institution: | 1. Department of Mathematics, Yeungnam University, Gyeongsan-si, Republic of Korea;2. Department of Mathematics and Informatics, Vilnius University, Naugarduko 24 LT-03225 Vilnius, Lithuania;3. Wen-Tsun Wu Key Laboratory of CAS, School of Mathematical Sciences, University of Science and Technology of China, Hefei, 23026, Anhui, China;4. School of Computing Sciences, University of East Anglia, Norwich, NR4 7TJ, UK |