Institution: | 1. Department of Mathematics, University of Washington, Seattle, WA 98195, USA;2. School of Mathematics and Information Science, North China University of Water Resources and Electric Power, Zhengzhou 450011, Henan, PR China;3. Institute of Contemporary Mathematics, School of Mathematics, Henan University, Kaifeng 475000, Henan, PR China;4. Department of Mathematics, Polytechnic Institute of New York University, Brooklyn, NY 11201, USA |