Problem Statement
Does there exist some $\epsilon>0$ such that, for all sufficiently large $n$, there exists a graph $G$ on $n$ vertices with at least $\epsilon n^2$ many edges such that the edges can be coloured with $n$ colours so that every $C_4$ receives $4$ distinct colours?
Categories:
Graph Theory Ramsey Theory
Progress
A problem of Burr, Erdős, Graham, and Sós.See also [809].
Source: erdosproblems.com/810 | Last verified: January 16, 2026