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isPlanar -- determines if a given graph is planar

Synopsis

Usage:

p = isPlanar G

p = isPlanar S
Inputs:
- S, a string, a graph encoded in either Sparse6 or Graph6 format
- G, a graph,
Outputs:
- p, a Boolean value, whether the given graph is planar

Description

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.

See also

onlyPlanar -- removes non-planar graphs from a list

Ways to use isPlanar :

isPlanar(Graph)
isPlanar(String)

For the programmer

The object isPlanar is a method function.