| Affiliation: | 1. Institute of Mathematical Sciences, Ewha Womans University, Seoul 03760, South Korea;2. Department of Mathematics, Ewha Womans University, Seoul 03760, South Korea;1. School of Mathematical Sciences, Qufu Normal University, Qufu Shandong, 273165, China;2. Department of Computing, Macquarie University, Sydney, NSW 2109, Australia;1. Universidade de São Paulo, Inst. de Ciências Matemáticas e de Computação, São Carlos, SP 13560-970, Brazil;2. Department of Mathematical Sciences, Faculty of Science, Yamagata University, Kojirakawa-machi 1-4-12, Yamagata 990-8560, Japan |
