  We consider a stationary Markovian evolution with values on a disjointly
partitioned set space $I\sqcup {\cal E}$. The evolution is visible (in the
sense of knowing the transition probabilities) on the states in $I$ but not for
the states in ${\cal E}$. One only knows some partial information on the
transition probabilities on ${\cal E}$, the input and output transition
probabilities and some constraints of the transition probabilities on ${\cal
E}$. Under some conditions we supply the transition probabilities on ${\cal E}$
that satisfies the maximum entropy principle.
