Affiliation: | Hsiao Ling Institute of Mathematics,Academy of Mathematics and Systems Science Chinese Academy of Sciences,Beijing 100190,China Li Hailiang Department of Mathematics,Capital Normal University,Beijing 100048,China Yang Tong Department of Mathematics,City University of Hong Kong,83 Tat Chee Avenue,Kowloon,Hong Kong,China Zou Chen Department of Mechanics and Aerospace Engineering,Peking University,Beijing 100871,China |