Counting symmetric colorings of G×ℤ2
Abstract
Let G be a finite group and let r∈ℕ. An r-coloring of G is any mapping χ:G→{1,…,r}. A coloring χ is symmetric if there is g∈G such that χ(gx−1g)=χ(x) for every x∈G. We show that if G is Abelian and f(r) is the polynomial representing the number of symmetric r-colorings of G, then the number of symmetric r-colorings of G×ℤ2 is f(r2). We also extend this result to the dihedral group D(G).
Communicated by T. H. Ha