Forbidden subgraphs for graphs with planar line graphs

AbstractLet G be a graph Sedláček [2] has shown that the line graph of G is planar if and only if G is planar, the degree of each point is at most four and all points of degree four are cutpoints.In this paper, we use this result to show that G has a planar line graph if and only if G has no subgraph homeomorphic to K3.3, K1.5, P4 + K1 or K2 + K3