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Sufficient conditions for graphs to be λ′-optimal, super-edge-connected, and maximally edge-connected

✍ Scribed by Angelika Hellwig; Lutz Volkmann


Publisher
John Wiley and Sons
Year
2005
Tongue
English
Weight
149 KB
Volume
48
Category
Article
ISSN
0364-9024

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✦ Synopsis


Abstract

The restricted‐edge‐connectivity of a graph G, denoted by λ′(G), is defined as the minimum cardinality over all edge‐cuts S of G, where GS contains no isolated vertices. The graph G is called λ′‐optimal, if λ′(G) = ξ(G), where ξ(G) is the minimum edge‐degree in G. A graph is super‐edge‐connected, if every minimum edge‐cut consists of edges adjacent to a vertex of minimum degree. In this paper, we present sufficient conditions for arbitrary, triangle‐free, and bipartite graphs to be λ′‐optimal, as well as conditions depending on the clique number. These conditions imply super‐edge‐connectivity, if δ (G) ≥ 3, and the equality of edge‐connectivity and minimum degree. Different examples will show that these conditions are best possible and independent of other results in this area. © 2005 Wiley Periodicals, Inc. J Graph Theory 48: 228–246, 2005


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