The well-known Erd\H{o}s-Hajnal conjecture states that for any graph $H$, there is a constant $c=c(H)>0$ such that every $n$-vertex graph $G$ with no induced copies of $H$ contains a clique or an independent set of size at least $n^{c}$. In this paper, we prove that the Erd\H{o}s-Hajnal conjecture holds for every path.
A dissociation set of a graph G is a vertex subset S contained in V(G) such that the induced subgraph G[S] has maximum degree at most 1, and the dissociation number of G is the cardinality of a maximum dissociation set denoted by {\Phi}(G). In this paper, we first derive a sharp lower bound on the dissociation number f...
Yuwen Zhou, Yuan-Yuan Chen, Dan Li et al.· 0 citations
In this paper we prove that every graph $G$ with no induced six-vertex path satisfies $\chi(G)\le \omega(G)^{c\log_2\omega(G)}$ for $c=45/\log_2(4/3)<109$. The best previous bound was exponential in $\omega(G)$. Our result is the first quasi-polynomial bound for $P_6$-free graphs and generalizes the bound for $P_5$-fre...