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A characterization of graphs without long induced paths

✍ Scribed by Gábor Bacsó; Zsolt Tuza


Publisher
John Wiley and Sons
Year
1990
Tongue
English
Weight
461 KB
Volume
14
Category
Article
ISSN
0364-9024

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✦ Synopsis


Abstract

In a connected graph define the k‐center as the set of vertices whose distance from any other vertex is at most k. We say that a vertex set S d‐dominates G if for every vertex x there is a y ∈ S whose distance from x is at most d.

Call a graph P~t~‐free if it does not contain a path on t vertices as an induced subgraph. We prove that a connected graph is P~2k‐1~‐free (P~2k~‐free) if and only if each of its connected induced subgraphs H satisfy the following property: The k‐center of H (k ‐ 1)‐dominates ((k ‐ 2)‐dominates) H.

Moreover, we show that the subgraph induced by the (t ‐ 3)‐center in any P~t~‐free connected graph is again connected and has diameter at most t ‐ 3.


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