Ramsey goodness of complete multipartite graphs with one large part

Abstract

For graph $G$, a connected graph $H$ of order $n$ is $G$-good if $r(G,H)=(χ(G)-1)(n-1)+s(G)$, where $χ(G)$ is the chromatic number of $G$ and $s(G)$ is the minimum size of a color class in a $χ(G)$-coloring of $G$. Let $K_{α_{1},\ldots ,α_{p},n}$ be the complete $(p+1)$-partite graph with partite sets of sizes $α_1,\ldots,α_p,n$. Burr, Faudree, Rousseau and Schelp (1983) showed that $K_{α_1,\ldots,α_p,n}$ are $(K_2+mK_1)$-good for large $n$. We determine graphs $G$ such that $K_{α_{1},\ldots ,α_{p},n}$ are $G$-good for large $n$. The characterization depends on $\mathrm{snd}(α_i)$, the smallest non-divisor of $α_i$, where $1\le i\le p$.