, it is the random variable that gives me how the last three links used up to the time i+2 have been appearing and G 1 (abc) := g 1 (a, b, c) for abc ∈ S := {111, 112, . . . , 221, 222}. According to the definition, we have that {Y i } i≥3 corresponds to a homogeneous Markov Chain with transition probability as follows: