“…The set m(G) is given by vz, ~31, (~1, v3,v41, 1~2, v3, ~4, {vi, vz, v,)l. It would seem that the set of meshes of G depends on the plane representation of G, but the fact is that if G is a planar, simple, triply connected graph, then m(G) is independent of the plane representation chosen to calculate the set of meshes. This property of planar, simple, triply connected graphs follows from the work of Whitney [2], [3] and is also enunciated in a paper by Mac Lane [4].…”