Graphic methods 10 Line graph Graph theory 6 Line graphs 6 Perfect graph 6 Balanced graphs 4 Bipartite graphs 4 Characterization 4 Coloring 4 Directed graphs 4 Graph coloring 4 Graph colorings 4 Hereditary clique-Helly graphs 4 Line graphs of trees 4 Minimum sum coloring 4 Perfect graphs 4 Set-coloring 4 Trees 4 Trees (mathematics) 4 All maximal cliques 2 Circular structures 2 Clique-perfect graphs 2 Edge coloring 2 Edge-coloring 2 Induced subgraphs 2 Matchings 2 Recognition algorithm 2