... joining {v2,v3,v4} and {v5,v6}.Fori =2, 3, 4, let N(vi) \ N[v]={vi}.Case 1. vi= vj for some i and j,where2≤ i<j≤ 4. We may assume that i =2 and j =3,andthatv7= v2.Ifv4= ... {v5,v6} and {v7,v8}.Since each of v5 and v6is at distance 3 from a degree-4 vertex (namely, v3 and v4),d(v5)=d(v6) = 3 by Observation 5. Further for i ≥ 9, d(v, vi) ≥ 3, and so, ... either v1or v4 and therefore, by Observation 4, has degree 3. By Observation 17, v4isthe only common neighbor of v8 and v10. By the claw-freeness of G, and by Observations 15 and 17, no two...