The design variable is denoted by a tuple x = {S, G}. Here, we write the model in Eq. 5 as Y (x) = f (x) = f (S|G) in order to explicitly express that the predicted property Y is a deterministic function of the reactant S and the reaction network G. As in our previous studies , molecular design based on Bayesian inference is performed based on the target distribution π(x), which is defined on P(B):