THE NUMBER OF CONTRACTIBLE EDGES IN A 4-CONNECTED GRAPH HAVING A SMALL NUMBER OF EDGES NOT CONTAINED IN TRIANGLES
Let Gbe a 4-connected graph, and let denote the set of those edges of Gwhich are not contained in a triangle and let denote the set of 4-contractible edges of G. We show that if or then
4-connected graph, contractible edge, triangle.
