Affiliation: | 1. Mathematical Institute, Slovak Academy of Sciences, Štefánikova 49, SK-814 73 Bratislava, Slovakia;2. Depart. Algebra Geom., Palacký Univer., 17. listopadu 12, CZ-771 46 Olomouc, Czech Republic;1. Department of Mathematical and Physical Sciences, Faculty of Science and Engineering, University of Chester, England, UK;2. Harmony School of Technology, Houston, TX 77038, USA;3. Department of Mathematics & Statistics, Northern Arizona University, Flagstaff, AZ 86001, USA;1. Computer Science Department, University of Victoria, Victoria, BC, V8W 2Y2, Canada;2. INRIA Saclay, 91120 Palaiseau, France;1. College of Information Technology, Hebei University of Economics and Business, Shijiazhuang, 050061, PR China;2. School of Computer Software, Tianjin University, Tianjin 300072, PR China;3. Chern Institute of Mathematics, Nankai University, Tianjin 300071, PR China |