For a graph G, let Ο 3 (G) = min{deg G x + deg G y + deg G z: {x, y, z} is an independent set in G}. Enomoto et al. [Enowoto et al., J Graph Theory 20 (1995), 419-422] have proved that the vertex set of a 2-connected graph G of order n with Ο 3 (G) β₯ n is covered by two cycles, edges or vertices. Ex
Degree Sums and Covering Cycles
β Scribed by Hikoe Enomoto; Atsushi Kaneko; Mekkia Kouider; Zsolt Tuza
- Publisher
- John Wiley and Sons
- Year
- 1995
- Tongue
- English
- Weight
- 194 KB
- Volume
- 20
- Category
- Article
- ISSN
- 0364-9024
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β¦ Synopsis
Abstract
It is shown that if in a simple graph G of order n the sum of degrees of any three pairwise nonβadjacent vertices is at least n, then there are two cycles (or one cycle and an edge or a vertex) of GF that contain all the vertices. Β© 1995 John Wiley & Sons, Inc.
π SIMILAR VOLUMES
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.
Let G be a graph of order n satisfying d(u) + d(v) β₯ n for every edge uv of G. We show that the circumference-the length of a longest cycle-of G can be expressed in terms of a certain graph parameter, and can be computed in polynomial time. Moreover, we show that G contains cycles of every length be
## Abstract For a graph __G__, we denote by __d__~__G__~(__x__) and ΞΊ(__G__) the degree of a vertex __x__ in __G__ and the connectivity of __G__, respectively. In this article, we show that if __G__ is a 3βconnected graph of order __n__ such that __d__~__G__~(__x__) + __d__~__G__~(__y__) + __d__~__
## Abstract Let __k__ and __n__ be two integers such that __k__ β₯ 0 and __n__ β₯ 3(__k__ + 1). Let __G__ be a graph of order __n__ with minimum degree at least β(__n__ + __k__)/2β. Then __G__ contains __k__ + 1 independent cycles covering all the vertices of __G__ such that __k__ of them are triangl
## Abstract Let __t__(__n, k__) denote the TurΓ‘n numberβthe maximum number of edges in a graph on __n__ vertices that does not contain a complete graph __K__~k+1~. It is shown that if __G__ is a graph on __n__ vertices with __n__ β₯ __k__^2^(__k__ β 1)/4 and __m__ < __t__(__n, k__) edges, then __G__