evel of abstraction that we adopt, the functioning of a biochemical reaction is based on facilitation and inhibition: a reaction can take place if all of its reactants are present and none of its inhibitors is present. If a reaction takes place, then it produces its product. Therefore a reaction is defined as a triplet a = (R, I, P), where R, I, P are finite sets called the reactant set of a, the inhibitor set of a, and the product set of a, and denoted by Ra, Ia, and Pa, respectively. If S is a set such that R, I, P ⊆ S, then we say that a is a reaction in S. Then a reaction a takes place (in a given state – a given molecular soup) if all of its reactants are present and none of its inhibitors is present. Consequently, for a finite set (state) T, a is enabled by T if Ra ⊆ T and Ia ∩ T = ∅. The result of a