Critically $n$-connected graphs
Critically $n$-connected graphs
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DOI:
10.1090/s0002-9939-1972-0290999-1
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发表时间:
1972
期刊:
影响因子:
--
通讯作者:
G. Chartrand;A. Kaugars;D. R. Lick
中科院分区:
文献类型:
--
作者:
G. Chartrand;A. Kaugars;D. R. Lick
The following result is proved. Every n-connected graph contains either a vertex whose removal results in a graph which is also n-connected or a vertex of degree less than (3n 1)/2. Introduction. A graph G is said to be n-connected if the removal of fewer than n vertices from G neither disconnects it nor reduces it to the trivial graph consisting of a single vertex. The maximum value of n for which a graph G is n-connected is called its connectivity and is denoted by K(G). The minimum degree of G is designated by 5(G); the inequality K(G)<6(G) is well known. A graph G is said to be critically n-connected if K(G)=n and K(G-v)= n-I for each vertex v of G. Analogously, a graph G is minimally nconnected if K(G)=n and for each edge e of G, K(G-e)=n1. The object of this article is to present a necessary condition for a graph to be critically n-connected and to discuss related topics. Since 1-connected graphs are the nontrivial connected graphs and since every nontrivial connected graph G has at least two vertices u and v such