## Abstract We show that every 1βtough graph __G__ on __n__ β₯ 3 vertices with Ο~3~β§ __n__ has a cycle of length at least min{__n, n__ + (Ο~3~/3 ) β Ξ± + 1}, where Ο~3~ denotes the minimum value of the degree sum of any 3 pairwise nonadjacent vertices and Ξ± the cardinality of a miximum independent se
A lower bound for the circumference of a graph
β Scribed by Nathan Linial
- Publisher
- Elsevier Science
- Year
- 1976
- Tongue
- English
- Weight
- 423 KB
- Volume
- 15
- Category
- Article
- ISSN
- 0012-365X
No coin nor oath required. For personal study only.
β¦ Synopsis
Lrzt G = (V, 0 be a ttlock :.>f order n, different from Kn. Let ~FI = min {d(x) + d(y): n then G contains a cycle of length at least m. 1. Introductlion and notatio e discuss only finite undirected graphs withsLc loops and multiple edges. We p:rosye the main theorem d show how Qre's th -orem [ 3.1 on Hamiltonian graphs is easily deduc Let 5; = ( V, E) be a graph where ', E are the vertex any! edge #sets respectively. The cardinality of a set ,S is denoted by ISI. II stan out for i VI, the order of @. Y'(x) is the set of vertices adjacent to x. d(x) = ~Rx-)l, the degree ofx A Mrck, or Gquivalently a Z-connected graph is a connected graph whit remitins connected after the deletion Qf any of its vertices. The &x~~#llrence of C, c(G) is the length of the .ngest cycle contained in G. [The I of a path or a cycle is the nu-er of ed 2'9 '7
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A non-isolated vertex of a graph G is called a groupie if the average degree of the vertices connected to it is larger than or equal to the average degree of the vertices in G. An isolated vertex is a groupie only if all vertices of G are isolated. While it is well known that every graph must contai
## Abstract Let __C__ be a longest cycle in the 3βconnected graph __G__ and let __H__ be a component of __G__βββ__V__(__C__) such that |__V__(__H__)|ββ₯β3. We supply estimates of the form |__C__|ββ₯β2__d__(__u__)β+β2__d__(__v__)βββΞ±(4ββ€βΞ±ββ€β8), where __u__,__v__ are suitably chosen nonβadjacent verti
We present a new condition on the degree sums of a graph that implies the existence of a long cycle. Let c(G) denote the length of a longest cycle in the graph G and let rn be any positive integer. Suppose G is a 2-connected graph with vertices x,, . . . , x, and edge set E that satisfies the proper