## Abstract Let __G__ be a graph on __n__ vertices and __N__~2~(__G__) denote the minimum size of __N__(__u__) βͺ __N__(__v__) taken over all pairs of independent vertices __u, v__ of __G__. We show that if __G__ is 3βconnected and __N__~2~(__G__) β©Ύ Β½(__n__ + 1), then __G__ has a Hamilton cycle. We
Neighborhood unions and hamiltonicity of graphs
β Scribed by Ruqun Shen; Feng Tian
- Publisher
- Elsevier Science
- Year
- 1995
- Tongue
- English
- Weight
- 530 KB
- Volume
- 141
- Category
- Article
- ISSN
- 0012-365X
No coin nor oath required. For personal study only.
β¦ Synopsis
Let G be a graph of order n. In this paper, we prove that if G is a 2-connected graph of order n such that for all u, ve V(G),
2 where dist(u,v) is the distance between u and v in G, then either G is hamiltonian, or G is a spanning subgraph of a graph in one of three families of exceptional graphs.
As a corollary, we get that if G is a 3-connected graph of order n such that for all u, ve V(G), n+3 dist(u,v)=2 ~ IN(u)wN(v)i>>-----, 2 then G is hamiltonian.
π SIMILAR VOLUMES
## Abstract Dirac proved that a graph __G__ is hamiltonian if the minimum degree $\delta(G) \geq n/2$, where __n__ is the order of __G__. Let __G__ be a graph and $A \subseteq V(G)$. The neighborhood of __A__ is $N(A)=\{ b: ab \in E(G)$ for some $a \in A\}$. For any positive integer __k__, we show
Bauer, D., G. Fan and H.J. Veldman, Hamiltonian properties of graphs with large neighborhood unions, Discrete Mathematics 96 (1991) 33-49. Let G be a graph of order n, a k =min{~ki=ld(vi): {V 1 ..... Vn} is an independent set of vertices in G}, NC=min{IN(u) 13N(v)l:uv~E(G)} and NC2=min{IN(u) t3 wh
## Abstract Let __G__ be a graph of order __n__ and define __NC(G)__ = min{|__N__(__u__) βͺ __N__(__v__)| |__uv__ β __E__(__G__)}. A cycle __C__ of __G__ is called a __dominating cycle__ or __D__β__cycle__ if __V__(__G__) β __V__(__C__) is an independent set. A __D__β__path__ is defined analogously.
We present and prove several results concerning the length of longest cycles in 2connected or I-tough graphs with large degree sums. These results improve many known results on long cycles in these graphs. We also consider the sharpness of the results and discuss some possible strengthenings.
## Abstract Let __G__ be a simple undirected graph of order __n__. For an independent set __S__ β __V__(__G__) of __k__ vertices, we define the __k__ neighborhood intersections __S__~__i__~ = {__v__ Ο΅ __V__(__G__)\__S__|__N__(__v__) β© S| = __i__}, 1 β¦ __i__ β¦ __k__, with __s__~__i__~ = |__S__~__i__