Planarity of iterated line graphs

The line index of a graph G is the smallest k such that the kth iterated line graph of G is nonplanar. We show that the line index of a graph is either innite or it is at most 4. Moreover, we give a full characterization of all graphs with respect to their line index. Key words: Line graph, Planarity

• Type: Journal
• Year: 2008
• Where: DM
• Authors: Mohammad Ghebleh, Mahdad Khatirinejad
• Keywords: DM 2008, Line Graph, Line Index, The Line