| Institution: | 1. Department of Mathematics, Cheju National University, Jeju 690-756, South Korea;2. Department of Mathematics, Kyunghee University, Suwon 449-701, South Korea;3. Department of Mathematics, Kyungpook National University, Daegu 702-701, South Korea;1. College of Mathematics and Statistics, Northwest Normal University, Lanzhou 730070, China;2. Department of Mathematics, Dingxi Teachers College, Dingxi 743000, China;1. Department of Mathematics, Finance University under the Government of Russian Federation, Leningradsky Prospect 49-55, 125468 Moscow, Russian Federation;2. Department of Algebra and Geometry, Palacky University, 17. listopadu 12, 77146 Olomouc, Czech Republic |
