- Usage:
`p = isPlanar G``p = isPlanar S`

- Outputs:
`p`, a Boolean value, whether the given graph is planar

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.

i1 : isPlanar graph {{0,1}, {1,2}, {2,3}, {3,4}, {0,4}} o1 = true |

i2 : isPlanar graph flatten for i from 0 to 4 list for j from i+1 to 4 list {i,j} o2 = false |

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.

- onlyPlanar -- removes non-planar graphs from a list

- isPlanar(Graph)
- isPlanar(String)