Figure 7

Step 3. Vertices ahead of v _j in the sorted neighbour list are found whose edges to both v _i and v _j are forward-compatible with e _min (solid edges). These vertices, shown in grey with a check beside them, form the vertex set of the subgraph H. Vertices in the sorted list which fail this test, due to the presence of one or more non-forward-compatible edges (dashed) are indicated with an X. Vertices to the right of the sorted list automatically fail the test - their edges to v _i have RPDs greater than R(e _min )·δ and therefore are not compatible with e _min due to the sorting of RPDs performed earlier.