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].
. [J]. Frontiers of Mathematics in China, 2016, 11(6): 1533-1567.
Ziwen HUANG,Xiangwen LI. Degree sum of a pair of independent edges and Z3-connectivity. Front. Math. China, 2016, 11(6): 1533-1567.
Jaeger F, Linial N, Payan C, Tarsi M. Group connectivity of graphs-a nonhomogeneous analogue of nowhere-zero flow properties. J Combin Theory Ser B, 1992, 56: 165–182
https://doi.org/10.1016/0095-8956(92)90016-Q
Lai H-J, Li X, Shao Y, Zhan M. Group connectivity and group colorings of graphs—a survey. Acta Math Sin (Engl Ser), 2011, 27: 405–434
https://doi.org/10.1007/s10114-010-9746-3
Lovász L M, Thomassen C, Wu Y, Zhang C-Q. Nowhere-zero 3-flows and modulo k-orientations. J Combin Theory Ser B, 2013, 103: 587–598
https://doi.org/10.1016/j.jctb.2013.06.003
Zhang X, Zhan M, Xu R, Shao Y, Li X, Lai H-J. Degree sum condition for Z3-connectivity in graphs. Discrete Math, 2010, 310: 3390–3397
https://doi.org/10.1016/j.disc.2010.08.004