  If $S$ is a subset of an abelian group $G$, the polychromatic number of $S$
in $G$ is the largest integer $k$ so that there is a $k-$coloring of the
elements of $G$ such that every translate of $S$ in $G$ gets all $k$ colors. We
determine the polychromatic number of all sets of size 2 or 3 in the group of
integers mod n.

Combinatorics;Group Theory