可不可以這樣用？以後有想到繼續補...

1.

Let X = (X₁, X₂, X₃, ..., X_T) be a sequence of random variables in finite set of states
S = (S₁, S₂, S₃, ..., S_N)

如果把X當成是term sequence，S可以是POS，concept or others

Reference: Part-of-speech tagging using a Variable Memory Markov model