We further assume that throughout the synthesis campaign, the set of functional modules is fixed, so no modules are added or removed from the laboratory. Given a reaction network and the operation graphs of its reactions, we can generate the operation network of this reaction network by connecting nodes from different operation graphs with directed (precedence) edges. Note these edges still represent required precedence relations among operations, thus the precedence of reaction A over reaction B in the reaction network does not imply all operations of reaction A must precede all operations of reaction B in the operation network. This network can be viewed as a State-Task Network where chemicals and operations are states and tasks, respectively.