On Ramsey goodness of $K_{2,n}$ versus cycles
Abstract
A graph is called -good if , where denotes the size of the smallest color class in a -coloring of . In Ramsey theory, it is an interesting problem to study whether a graph is -good or not. In this article, we study the Ramsey goodness of the pair , which naturally lies between the classical star-cycle and book-cycle problems. We prove that \begin{equation*} R(K_{2,n},C_{\{m,m+1\}})=m+1. \end{equation*} for all , and consequently establish that \begin{equation*} R(K_{2,n},C_{m})=m+1. \end{equation*} for all . This proves that is -good in this range and improves a particular case of a result on the Ramsey goodness by Pokrovskiy and Sudakov. Further, we provide a construction of a graph that disproves the -goodness of for all even satisfying .
Cite
@article{arxiv.2605.06253,
title = {On Ramsey goodness of $K_{2,n}$ versus cycles},
author = {Abisek Dewan and Sayan Gupta and Rajiv Mishra},
journal= {arXiv preprint arXiv:2605.06253},
year = {2026}
}
Comments
16 pages, 3 figures