证明了任一马氏过程X(t,ω),若用一停时α(w)去截X(t,w)的样本轨道,则截断前的样本轨道函数在满足条件{α〉t}∈F的条件下是一马氏过程,同时得到了截断后的样本轨道函数也是一马氏过程。另外,对于任意的随机过程,证明了X(t,ω)的t前σ一代数F1满足右连续性(即F1=∩s>tFs),以及任一首达时间是一停时。
It is proved that the truncated sample path function of a Markov process X(t,ω) prior to a (ω) is still a Markov process if { a 〉 t } ∈ Ft^∞ for every t ≥0 , and the one after a (ω) is also a Markov process. Moreover, for an arbitrary stochastic process X(t,ω) which may not be a Markov process, it is showed that the or -algebra F, prior to t of X(t,ω) is right continuous ( i. e. , F1 = ∩s〉tFs ) and the first hitting time is a stopping time.