For positive integers k less than or equal to n, the crown C-n,C-k is the graph with vertex set {a(1), a(2),...,a(n), b(1), b(2),...,b(n)} and edge set {a(i)b(j): 1 less than or equal to i less than or equal to n, j = i, i + 1,..., i + k - 1 (mod n)}. In
