Figure 9.

Matching Index. V₁ is connected with 5 nodes (V₃, V₄, V₆, V_7,V₈). V₂ is connected with 4 nodes (V₃, V₄, V₅, V₈). V₃ is connected with 2 nodes (V₁, V₂). V₄ is connected with 3 nodes (V₁, V₂). V₅ is connected with 1 node (V₂). V₆ is connected with 1 node (V₁). V₇ is connected with 1 node (V₁). V₈ is connected with 2 nodes (V₁, V₅). Node V₁ and V₂ are connected with 3 common nodes (V₃, V₄, V₈)and in total with 6 distinct neighbors (V₃, V₄, V₈, V₅, V₆ , V₇). The matching index will then be M_1,2 = 3/6 = 0.5, thus V₁ and V₂ are functionally similar even though they are not connected.