3 problems

Let $k$ be a positive integer. A $k$-edge-coloured tournament is a tournament whose edges are assigned colours from a set of $k$ colours. A cycle of length $3$ is polychromatic whe…

A 3-edge-coloured tournament is a tournament whose edges are assigned one of three colours. A directed cycle is a directed dicycle, and a dicycle is polychromatic when its edges do…

Let $k$ be a positive integer. A $k$-edge-coloured finite tournament is a finite tournament whose edges are assigned one of $k$ colours, and a set $S\subseteq V(T)$ is reachable fr…