Institution: | 1. Lihui Tian and Guanying Wang are at the Institute of Finance and Development, Nankai University, Tianjin, China;2. Xingchun Wang and Yongjin Wang are at the School of Mathematical Sciences and LPMC, Nankai University, Tianjin, China;3. Xingchun Wang is also at the Mathematical Institute, University of Oxford, Oxford, UK;4. Yongjin Wang is also at the School of Business, Nankai University, Tianjin, China |