ArticleOriginal scientific text

Title

On a family of cubic graphs containing the flower snarks

Authors 1, 1, 1

Affiliations

  1. L.I.F.O., Faculté des Sciences, B.P. 6759, Université d'Orléans, 45067 Orléans Cedex 2, France

Abstract

We consider cubic graphs formed with k ≥ 2 disjoint claws CiK1,3 (0 ≤ i ≤ k-1) such that for every integer i modulo k the three vertices of degree 1 of Ci are joined to the three vertices of degree 1 of Ci-1 and joined to the three vertices of degree 1 of Ci+1. Denote by ti the vertex of degree 3 of Ci and by T the set {t,t,...,tk-1}. In such a way we construct three distinct graphs, namely FS(1,k), FS(2,k) and FS(3,k). The graph FS(j,k) (j ∈ {1,2,3}) is the graph where the set of vertices i=0i=k-1V(Ci)T induce j cycles (note that the graphs FS(2,2p+1), p ≥ 2, are the flower snarks defined by Isaacs [8]). We determine the number of perfect matchings of every FS(j,k). A cubic graph G is said to be 2-factor hamiltonian if every 2-factor of G is a hamiltonian cycle. We characterize the graphs FS(j,k) that are 2-factor hamiltonian (note that FS(1,3) is the "Triplex Graph" of Robertson, Seymour and Thomas [15]). A strong matching M in a graph G is a matching M such that there is no edge of E(G) connecting any two edges of M. A cubic graph having a perfect matching union of two strong matchings is said to be a Jaeger's graph. We characterize the graphs FS(j,k) that are Jaeger's graphs.

Keywords

cubic graph, perfect matching, strong matching, counting, hamiltonian cycle, 2-factor hamiltonian

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Pages:
289-314
Main language of publication
English
Received
2008-12-31
Accepted
2009-09-17
Published
2010
Exact and natural sciences