P = onlyPlanar L
P = onlyPlanar(L, non)
A graph is planar if the graph can be embedded in the plane, i.e., the vertices can be arranged such that no edges cross except at vertices.
The only nonplanar graph on five vertices is the complete graph.



This method uses the program planarg. The code was written by Paulette Lieby for the Magma project and used with permission in the software nauty.
The object onlyPlanar is a method function.