Let I(t) be the set of integers with the property that in every Pt-free connected graph G, the i-center C,(G) induces a connected subgraph. What is the minimum element of /(t)? In this paper, we prove that this minimum is [2t/3] -1 if t = 0 or Z(mod3) and is [ 2 t / 3 ] otherwise. Furthermore, as co
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
No coin nor oath required. For personal study only.
✦ 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.
📜 SIMILAR VOLUMES
A graph G is said to be P t -free if it does not contain an induced path on t vertices. The i-center C i (G) of a connected graph G is the set of vertices whose distance from any vertex in G is at most i. Denote by I(t) the set of natural numbers i, t/2 ≤ i ≤ t -2, with the property that, in every c
## Abstract A path graph is the intersection graph of subpaths of a tree. In 1970, Renz asked for a characterization of path graphs by forbidden induced subgraphs. We answer this question by determining the complete list of graphs that are not path graphs and are minimal with this property. © 2009
## Abstract It is proved that for every positive integers __k__, __r__ and __s__ there exists an integer __n__ = __n__(__k__,__r__,__s__) such that every __k__‐connected graph of order at least __n__ contains either an induced path of length __s__ or a subdivision of the complete bipartite graph __
## Abstract Broersma and Hoede have introduced path graphs. Their characterization of __P__~3~‐graphs contains a flaw. This note presents the correct form of the characterization. © 1993 John Wiley & Sons, Inc.
## For a graph G and an integer an independent set of vertices in G}. Enomoto proved the following theorem. Let s ≥ 1 and let G be a (s + 2)-connected graph. Then G has a cycle of length ≥ min{|V (G)|, σ 2 (G) -s} passing through any path of length s. We generalize this result as follows. Let k ≥