## Abstract We characterize (by forbidden induced subgraphs) those line‐graphs that are perfectly orderable. Implicit in our presentation is a polynomial, time algorithm for recognizing these graphs.
Iterated line graphs are maximally ordered
✍ Scribed by Martin Knor; L'udovít Niepel
- Publisher
- John Wiley and Sons
- Year
- 2006
- Tongue
- English
- Weight
- 110 KB
- Volume
- 52
- Category
- Article
- ISSN
- 0364-9024
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✦ Synopsis
Abstract
A graph G is k‐ordered if for every ordered sequence of k vertices, there is a cycle in G that encounters the vertices of the sequence in the given order. We prove that if G is a connected graph distinct from a path, then there is a number t~G~ such that for every t ≥ t~G~ the t‐iterated line graph of G, L^t^ (G), is (δ(L^t^ (G)) + 1)‐ordered. Since there is no graph H which is (δ(H)+2)‐ordered, the result is best possible. © 2006 Wiley Periodicals, Inc. J Graph Theory 52: 171–180, 2006
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