The Vertex coloring of the double outer planar graph
Liu Guang-d · 2013
The graph coloring problem is one of the important problems of graph theory. The article studies the double outer planar graph G of chromatic number,and proved( 1) Without cut points,when the number of vertices is 6n + k( n = 1,2,...)( k= 1,2,3),χv= 4; orχv= 3.( 2) χv= 4when the vertex labeling conflict at the ends of the same surface,if the cut points on this label relative at the edge,there are still χv= 4; or χv= 4.