MAYGEN generates constitutional isomers of a given molecular formula with an orderly graph generation algorithm from the field of algorithmic group theory. The principles are described in detail in . We summarize them in the following. A graph with p nodes, has its symmetry group . This symmetry group includes all the permutations {1, 2, 3, …, 𝑝} 𝑆 𝑝 of these nodes. However, for the case of coloured graphs, the nodes need to be partitioned (Equation ), in other words, nodes are grouped based on their colours, degrees and edges.