English

A note on the Ramsey number of even wheels versus stars

Combinatorics 2015-10-30 v1

Abstract

For two graphs G1G_1 and G2G_2 the Ramsey number R(G1,G2)R(G_1,G_2) is the smallest integer NN, such that for any graph on NN vertices either GG contains G1G_1 or G\overline{G} contains G2G_2. Let SnS_n be a star of order nn and WmW_m be a wheel of order m+1m+1. In this paper, it is shown that R(Wn,Sn)5n/21R(W_n,S_n)\leq{5n/2-1}, where n6n\geq{6} is even. It was proven a theorem which implies that R(Wn,Sn)5n/22R(W_n,S_n)\geq{5n/2-2}, where n6n\geq{6} is even. Therefore we conclude that R(Wn,Sn)=5n/22R(W_n,S_n)=5n/2-2 or 5n/215n/2-1, for n6n\geq{6} and even.

Keywords

Cite

@article{arxiv.1510.08488,
  title  = {A note on the Ramsey number of even wheels versus stars},
  author = {Sh. Haghi and H. R. Maimani},
  journal= {arXiv preprint arXiv:1510.08488},
  year   = {2015}
}