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 non-planar graph on five vertices is the complete graph.
i1 : K5 = graph flatten for i from 0 to 4 list for j from i+1 to 4 list {i,j}; |
i2 : P = onlyPlanar(generateGraphs 5, true) o2 = {D~{} o2 : List |
i3 : areIsomorphic(first P, K5) o3 = true |
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.