G = (V, E) a graph with V = {1, . . . , n}. We have the function f : V → V defined
f (v) = min{u|u ∈ V, dG (v, u) ≤ 2}.Demostrate that vw ∈ E(G) with f (v) != f (w) then G has the
P4 subgraph induced
I don;t understand what to demostrate/to do. Any advice?