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An extremal problem on potentially K_p1,p2,...,pt-graphic sequences

2004/08/24 by Chunhui Lai, Lai, Chunhui
Mathematics · #05C07 #05C35 #Combinatorics (math.CO) #FOS: Mathematics #math.CO #msc:05C07 #msc:05C35

paper · pdf · doi:10.48550/arxiv.math/0408326

4 pages

arxiv created 2004/08/24 · arxiv updated 2009/12/01

Abstract

A sequence S is potentially K_p1,p2,...,pt graphical if it has a realization containing a K_p1,p2,...,pt as a subgraph, where K_p1,p2,...,pt is a complete t-partite graph with partition sizes p1,p2,...,pt (p1≥ p2≥ ...≥ pt ≥ 1). Let σ(K_p1,p2,...,pt, n) denote the smallest degree sum such that every n-term graphical sequence S with σ(S)≥ σ(K_p1,p2,...,pt, n) is potentially K_p1,p2,...,pt graphical. In this paper, we prove that σ(K_p1,p2,...,pt, n)≥ 2[((2p1+2p2+...+2pt-p1-p2-...-pi-2)n -(p1+p2+...+pt-pi)(pi+pi+1+...+pt-1)+2)/2] for n ≥ p1+p2+...+pt, i=2,3,...,t.

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