PASSPORT OPTIONS
将护照期权理论与鞅理论及贝塞尔过程联系起来，通过连续鞅上的范数等式计算期权价格，并解决了离散时间情形。
We relate the theory of passport options with general principles from martingale theory as well as with the theory of Bessel processcs. The calculation of the price of a passport option leads to an equality between two norms on continuous martingales. We also solve the discrete time case for passport options.