## Abstract A graph is locally connected if for each vertex ν of degree __≧2__, the subgraph induced by the vertices adjacent to ν is connected. In this paper we establish a sharp threshold function for local connectivity. Specifically, if the probability of an edge of a labeled graph of order __n_
A local structure theorem on 5-connected graphs
✍ Scribed by Kiyoshi Ando
- Publisher
- John Wiley and Sons
- Year
- 2009
- Tongue
- English
- Weight
- 281 KB
- Volume
- 60
- Category
- Article
- ISSN
- 0364-9024
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
An edge of a 5‐connected graph is said to be contractible if the contraction of the edge results in a 5‐connected graph. Let x be a vertex of a 5‐connected graph. We prove that if there are no contractible edges whose distance from x is two or less, then either there are two triangles with x in common each of which has a distinct degree five vertex other than x, or there is a specified structure called a K~4~^−^‐configuration with center x. As a corollary, we show that if a 5‐connected graph on n vertices has no contractible edges, then it has 2__n__/5 vertices of degree 5. © 2008 Wiley Periodicals, Inc. J Graph Theory 60: 99–129, 2009
📜 SIMILAR VOLUMES
## Abstract In this note a shortened proof is given for the Faudree—Schelp theorem on path‐connected graphs.
In this paper w e determine the circumstances under which a set of 11 vertices in a 3-connected cubic graph lies on a cycle. In addition, w e consider the number of such cycles that exist and characterize those graphs in which a set of 9 vertices lies in exactly two cycles.
## Abstract For a vertex __v__ of a graph __G__, we denote by __d__(__v__) the __degree__ of __v__. The __local connectivity__ κ(__u, v__) of two vertices __u__ and __v__ in a graph __G__ is the maximum number of internally disjoint __u__ –__v__ paths in __G__, and the __connectivity__ of __G__ is
An element e of a 3-connected matroid M is essential if neither the deletion M\e nor the contraction M/e is 3-connected. Tutte's Wheels and Whirls Theorem proves that the only 3-connected matroids in which every element is essential are the wheels and whirls. In this paper, we consider those 3-conne
proved that if G is a 2-connected graph with n vertices such that d(u)+d(v)+d(w) n+} holds for any triple of independent vertices u, v, and w, then G is hamiltonian, where } is the vertex connectivity of G. In this note, we will give a short proof of the above result.