Erdős–Hajnal conjecture for rainbow triangles

Let $r$ and $t$ be positive integers, and let $r(t)$ denote the two-color Ramsey number: the least integer $m$ such that every $2$-coloring of the edges of the complete graph on $m$ vertices contains a monochromatic clique of order $t$. Define

$$N(r,t)=\left(r(t)-1\right)^{r/2}$$

when $r$ is even, and

$$N(r,t)=(t-1)\left(r(t)-1\right)^{(r-1)/2}$$

when $r$ is odd. A coloring of the edges of a complete graph is a rainbow triangle if some triangle has three differently colored edges, and a monochromatic $K_t$ is a complete subgraph on $t$ vertices whose edges all have one color. Erdős–Hajnal conjecture. For $n>N(r,t)$, every $r$-coloring of the edges of the complete graph on $n$ vertices has a rainbow triangle or a monochromatic $K_t$.

This conjecture asserts that the lexicographic-product constructions described in the paper give the best possible bounds for avoiding both rainbow triangles and monochromatic cliques. It was verified by Chung and Graham in the case $t=3$; the general case remains open in the supplied source.