A Important Property on Planar Graph
Na Na Li, Shujun Wang, Xian Rui Meng · Applied Mechanics and Materials · 2011
In 1994, C.Thomassen proved that every planar graph is (namely ). In 1993, M.Voigt shown that there are planar graphs which are not . But no one know whether every planar graph is . In this paper, we give a important property on planar graph that “Every planar graph is ” and “Every planar graph is free ” are equivalent.