Simple graphs G = (V, E ) and H = (W, F )
are isomorphic if there exists an isomorphism from G to H.
An isomorphism from G to H is a bijection
f : V → W so that, for every pair of different
vertices u ∈ V and v ∈ V,
{u,v} ∈ E if and only if
{f (u), f (v)} ∈ F.