萧焚 发表于 2014-11-12 00:16
另外,随机过程是个二元函数,按理说对它的积分应该是二重积分,但我认为正是它把其中的随机性这个自变量处 ...
No, let's say an Ito integral: ∫H(s)dX(s). The stochastic integral itself is a stochastic variable (in time space). It is a single integral. But if you take the expectation of it E(∫H(s)dX(s)) the expectation itself is a integral (it is an integral with respect to the the probability measure (in sample space)) then it is a double integral. Stochastic integral is defined on the time line, itself is a stochastic variable.