1. Department of Applied Mathematics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong;
2. Research Centre for Quantitative Finance, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong;
3. Department of Mathematics, Humboldt University Berlin, 10099 Berlin, Germany;
4. School of Business and Economics, Humboldt University Berlin, 10099 Berlin, Germany;
5. College of Mathematics and Physics, Wenzhou University, Wenzhou 325035, People’s Republic of China