A molecule can be represented as a coloured graph. For 4 isomers of C 8 O 2 H 16 (Figure ), all atoms are coloured by their element types. . For the case of this node partition, the symmetry group of 26 nodes, , cannot be used 𝑆 26 since the nodes are coloured. In this case, a special type of symmetry group is applied, consisting of Young subgroups, that are the symmetry groups built based on the initial node partition (Equation 2 and 3). these symmetry groups only permute each element type within their groups, such as oxygens, carbons and hydrogens. The Young subgroups are then used for the construction of molecules' automorphism groups (Equation ). These atom partitions and symmetry groups are the core part of the MAYGEN canonical test.