A finite graph is planar iff it does not contain a subdivision of K_5 or K_{3,3} as a subgraph. Wagner's theorem is the minor-closed version (no K_5 or K_{3,3} minor). Companion to Euler's formula V − E + F = 2 for connected planar…
A finite graph is planar iff it does not contain a subdivision of K_5 or K_{3,3} as a subgraph. Wagner's theorem is the minor-closed version (no K_5 or K_{3,3} minor). Companion to Euler's formula V − E + F = 2 for connected planar…