2003/08/11 by Chunhui Lai
Mathematics · #math.CO #msc:05C07 #msc:05C35
published as Australasian Journal of Combinatorics, 24(2001), 123-127 · 5 pages
arxiv created 2003/08/11 · arxiv updated 2009/12/01
A sequence S is potentially K4-e graphical if it has a realization containing a K4-e as a subgraph. Let σ(K4-e, n) denote the smallest degree sum such that every n-term graphical sequence S with σ(S)≥ σ(K4-e, n) is potentially K4-e graphical. Gould, Jacobson, Lehel raised the problem of determining the value of σ(K4-e, n). In this paper, we prove that σ(K4-e, n)=2[(3n-1)/2] for n≥ 7, and n=4,5, and σ(K4-e, 6)= 20.