Ramsey numbers for trees
Combinatorics
2014-10-28 v6
Abstract
For n≥5 let Tn′ denote the unique tree on n vertices with Δ(Tn′)=n−2, and let Tn∗=(V,E) be the tree on n vertices with V={v0,v1,…, vn−1} and E={v0v1,…,v0vn−3, vn−3vn−2,vn−2vn−1}. In this paper we evaluate the Ramsey numbers r(Gm,Tn′) and r(Gm,Tn∗), where Gm is a connected graph of order m. As examples, for n≥8 we have r(Tn′,Tn∗)=r(Tn∗,Tn∗)=2n−5, for n>m≥7 we have r(K1,m−1,Tn∗)=m+n−3 or m+n−4 according as m−1∣(n−3) or m−1∤(n−3), for m≥7 and n≥(m−3)2+2 we have r(Tm∗,Tn∗)=m+n−3 or m+n−4 according as m−1∣(n−3) or m−1∤(n−3).
Cite
@article{arxiv.1103.2685,
title = {Ramsey numbers for trees},
author = {Zhi-Hong Sun},
journal= {arXiv preprint arXiv:1103.2685},
year = {2014}
}
Comments
10 pages