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Degree sum of a pair of independent edges and Z3-connectivity |
Ziwen HUANG,Xiangwen LI() |
Department of Mathematics, Huazhong Normal University, Wuhan 430079, China |
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Abstract Let G be a 2-edge-connected simple graph on n vertices. For an edge e = uv ∈ E(G), define d(e) = d(u) + d(v). Let ℱ denote the set of all simple 2-edge-connected graphs on n≥4 vertices such that G ∈ ℱ if and only if d(e) + d(e')≥2n for every pair of independent edges e, e' of G. We prove in this paper that for each G ∈ ℱ, G is not Z3-connected if and only if G is one of K2,n−2, K3,n−3, K+2,n−2, K+3,n−3 or one of the 16 specified graphs, which generalizes the results of X. Zhang et al. [Discrete Math., 2010, 310: 3390–3397] and G. Fan and X. Zhou [Discrete Math., 2008, 308: 6233–6240].
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Keywords
Z3-connectivity
nowhere-zero 3-flow
degree condition
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Corresponding Author(s):
Xiangwen LI
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Issue Date: 18 October 2016
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