English

An Extremal Problem On Potentially $K_{r+1}-H$-graphic Sequences

Combinatorics 2010-02-06 v4

Abstract

Let KkK_k, CkC_k, TkT_k, and PkP_{k} denote a complete graph on kk vertices, a cycle on kk vertices, a tree on k+1k+1 vertices, and a path on k+1k+1 vertices, respectively. Let KmHK_{m}-H be the graph obtained from KmK_{m} by removing the edges set E(H)E(H) of the graph HH (HH is a subgraph of KmK_{m}). A sequence SS is potentially KmHK_{m}-H-graphical if it has a realization containing a KmHK_{m}-H as a subgraph. Let σ(KmH,n)\sigma(K_{m}-H, n) denote the smallest degree sum such that every nn-term graphical sequence SS with σ(S)σ(KmH,n)\sigma(S)\geq \sigma(K_{m}-H, n) is potentially KmHK_{m}-H-graphical. In this paper, we determine the values of σ(Kr+1H,n)\sigma (K_{r+1}-H, n) for n4r+10,r3,r+1k4n\geq 4r+10, r\geq 3, r+1 \geq k \geq 4 where HH is a graph on kk vertices which contains a tree on 4 vertices but not contains a cycle on 3 vertices. We also determine the values of σ(Kr+1P2,n)\sigma (K_{r+1}-P_2, n) for n4r+8,r3n\geq 4r+8, r\geq 3. There are a number of graphs on kk vertices which containing a tree on 4 vertices but not containing a cycle on 3 vertices (for example, the cycle on kk vertices, the tree on kk vertices, and the complete 2-partite graph on kk vertices, etc).

Keywords

Cite

@article{arxiv.math/0603265,
  title  = {An Extremal Problem On Potentially $K_{r+1}-H$-graphic Sequences},
  author = {Chunhui Lai and Lili Hu},
  journal= {arXiv preprint arXiv:math/0603265},
  year   = {2010}
}

Comments

10 pages

R2 v1 2026-07-22T17:32:44.793Z