If you are given a finite fumber of r.v. say $X_1...X_n$ and you know say the conditional distribution of each one given the preceding ones (i.e with smaller index) values , and you also know the marginal say $X_1$ then there is a unique measure satisfying these conditions
I am curious wether this generalizes to an infinite family indexed say by $R$. The marginal distributions could be expressed given the sigma algebra generated by the preceding ones.