SynGraph represents the connectivity between Chemical Equation and Molecule instances as a graph-like object. In a typical embodiment, based on a monopartite graph, directed edges connect Chemical Equation nodes, implying the reaction intermediates (Fig. ). Alternatively, directed edges of a monopartite graph connect Molecule nodes, implicitly suggesting chemical reactions (Fig. ). As a third alternative, Chemical Equations and Molecules are nodes of a bipartite graph where directed edges map role relationships (reactant, product, etc.) (Fig. ). While containing the same information, these and other graph data models might serve as alternative data representations fitting specific applications. We represent the domain logic through the following formal operations, acting on the SynGraph data model.