|WikiProject Mathematics||(Rated Start-class, Low-priority)|
Related to digons?
"A planar graph remains planar if an edge is added between two vertices already joined by an edge; thus, adding multiple edges preserves planarity." Isn't this similar to how adding digon faces to a polyhedron doesn't make any difference to the polyhedron's external appearance? Double sharp (talk) 10:18, 24 July 2012 (UTC)