We show that for any set $S\subseteq \mathbb{ Z}$, $|S|=4$ there exists a 3-coloring of $\mathbb{ Z}$ in which every translate of $S$ receives all three colors. This implies that $S$ has a codensity of at most $1/3$, proving a conjecture of Newman [D. J. Newman, Complements of finite sets of integers, Michigan Math. J. 14 (1967) 481--486]. We also consider related questions in $\mathbb{ Z}^d$, $d\geq 2$.
Categories: math.CO