The exclusion of duplicate nodes by assigning their mass to be zero guarantees this. It also removes an issue similar to the one discussed for Rules 1a and 1b, that different arrangements of double bonds in conjugates systems must not affect the chirality. For example, isotopically labeled alcohol VS007, shown in Figure , is achiral. To ensure this result, we simply assign all duplicate node masses to be zero, allowing the mass difference to be carried only by their corresponding duplicated atom. As mentioned above, generation of a complete digraph, including auxiliary descriptors, is required prior to Rule 3 (not just Rule 4a, as mentioned in BB 2013). This is because seqcis and seqtrans also describe double bonds that involve two diastereomorphic ligands on the same end (with stereodescriptors RR and SR, for example). Inverting about a plane changes the comparison (to SS and RS, in this case), but this change does not reverse priorities.