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2-factors in claw-free graphs

Guantao Chen, Jill R. Faudree, Ronald J. Gould, Akira Saito (2000)

Discussiones Mathematicae Graph Theory

We consider the question of the range of the number of cycles possible in a 2-factor of a 2-connected claw-free graph with sufficiently high minimum degree. (By claw-free we mean the graph has no induced K 1 , 3 .) In particular, we show that for such a graph G of order n ≥ 51 with δ(G) ≥ (n-2)/3, G contains a 2-factor with exactly k cycles, for 1 ≤ k ≤ (n-24)/3. We also show that this result is sharp in the sense that if we lower δ(G), we cannot obtain the full range of values for k.

2-factors in claw-free graphs with locally disconnected vertices

Mingqiang An, Liming Xiong, Runli Tian (2015)

Czechoslovak Mathematical Journal

An edge of G is singular if it does not lie on any triangle of G ; otherwise, it is non-singular. A vertex u of a graph G is called locally connected if the induced subgraph G [ N ( u ) ] by its neighborhood is connected; otherwise, it is called locally disconnected. In this paper, we prove that if a connected claw-free graph G of order at least three satisfies the following two conditions: (i) for each locally disconnected vertex v of degree at least 3 in G , there is a nonnegative integer s such that v lies...

γ-Cycles And Transitivity By Monochromatic Paths In Arc-Coloured Digraphs

Enrique Casas-Bautista, Hortensia Galeana-Sánchez, Rocío Rojas-Monroy (2013)

Discussiones Mathematicae Graph Theory

We call the digraph D an m-coloured digraph if its arcs are coloured with m colours. If D is an m-coloured digraph and a ∈ A(D), colour(a) will denote the colour has been used on a. A path (or a cycle) is called monochromatic if all of its arcs are coloured alike. A γ-cycle in D is a sequence of vertices, say γ = (u0, u1, . . . , un), such that ui ≠ uj if i ≠ j and for every i ∈ 0, 1, . . . , n there is a uiui+1-monochromatic path in D and there is no ui+1ui-monochromatic path in D (the indices...

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