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onlyPlanar -- removes non-planar graphs from a list



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.

See also

Ways to use onlyPlanar :

For the programmer

The object onlyPlanar is a method function.