Planar graphs An undirected graph is called a planar graph if it can be drawn on a paper without having two edges cross.
We say that a graph can be embedded in the plane, if it planar. A planar graph divides the plane into regions (bounded by the edges), called faces. The following planar graph has 4 faces.
1 Susanna S. Epp. Discrete Mathematics with Applications, Fourth Edition. Printed in Canada 2011p.p.626
2 Susanna S. Epp. Discrete Mathematics with Applications, Fourth Edition. Printed in Canada 2011p.p.625
3 Susanna S. Epp. Discrete Mathematics with Applications, Fourth Edition. Printed in Canada 2011p.p.627
