 Assuming that the system of equations is acyclic, an assignment of values to the exogenous variables \(U_1\), \(U_2\),… ,\(U_n\) uniquely determines the values of all the variables in the model. Then, if we have a probability distribution \(\Pr'\) over the values of variables in \(\bU\), this will induce a unique probability distribution P on \(\bV\).