Rainbow variations on a theme by Mantel: extremal problems for Gallai colouring templates

Victor Falgas-Ravry, Klas Markström, Eero Räty

Let $\mathbf{G}:=(G_1,G_2,G_3)$ be a triple of graphs on the same vertex set $V$ of size $n$. A rainbow triangle in $\mathbf{G}$ is a triple of edges $(e_1,e_2,e_3)$ with $e_i\…