Appendix A G ED and S ED The computation of G

Example 1 Figure 1 shows a graph mapping. Edge mappings can be trivially inferred. Hence, the claim is proved. These four cases cover all possible situations and hence, the triangle inequality is established. From the triangle inequality, we can infer the lower bounds listed in lines 2 and 4 of Alg. 2. Hence, if Alg. 3 presents the pseudocode.