Ramsey numbers for trees II
Combinatorics
2023-02-17 v5
Abstract
Let r(G1,G2) be the Ramsey number of the two graphs G1 and G2. For n1≥n2≥1 let S(n1,n2) be the double star given by V(S(n1,n2))={v0,v1,…,vn1,w0,w1,…,wn2} and E(S(n1,n2))={v0v1,…,v0vn1,v0w0,w0w1,…,w0wn2}. In this paper we determine r(K1,m−1, S(n1,n2)) under certain conditions. For n≥6 let Tn3=S(n−5,3), Tn′′=(V,E2) and Tn′′′=(V,E3), where V={v0,v1,…,vn−1}, E2={v0v1,…,v0vn−4,v1vn−3,v1vn−2, v2vn−1} and E3={v0v1,…,v0vn−4,v1vn−3,v2vn−2,v3vn−1}. We also obtain explicit formulas for r (K1,m−1,Tn), r(Tm′,Tn) (n≥m+3), r(Tn,Tn), r(Tn′,Tn) and r(Pn,Tn), where Tn∈{Tn′′,Tn′′′,Tn3}, Pn is the path on n vertices and Tn′ is the unique tree with n vertices and maximal degree n−2.
Cite
@article{arxiv.1410.7637,
title = {Ramsey numbers for trees II},
author = {Zhi-Hong Sun},
journal= {arXiv preprint arXiv:1410.7637},
year = {2023}
}
Comments
25 pages (published version)