Sub-/Super-Set We consider a synthetic route (SR2 in Figure ) to be a subset of another synthetic route (SR1) if it shares only a portion of the synthetic steps. The case where the target compound is shared is chemically relevant, and it represents the case when upon truncating a route branch, an intermediate is sourced rather than synthesized. The sub-set assessment between routes efficiently leverages the underlying dictionary data structure of SynGraph rather than relying on potentially expensive graph isomorphism algorithms. Similarity The equivalence (and the identity) is a Boolean response obtained by an equality function. On the contrary, the similarity is a numerical response obtained by comparing the numerical properties of two objects. By extending the molecular similarity approach to routes, we could compare the numerical values of route descriptors or hash the descriptors into route fingerprints and compare these instead.