摘要
A graph G is said to be embedded in a graph H, written, if there exists an isomorphism φ of G onto a subgraph G’ of H. Such an isomorphism φ is called an embedding of Ginto H. In 1982, D. Bauer and R. Tindell defined an invariant for graphs G, G neither a path nor K1,3, by setting ∧（G） equal to the least n≥1 for which GL*（G）. They have studied graphs with ∧ （G）=1, and posed questions of studying graphs with ∧ （G）=2 and of determining ∧（T） for all trees T. We have also studied the questions and have further studied graphs G such that G embeds in its iterated line-graph Ln（G）.
