“…In investigating the (S1),(S2),(S3) conditions of Theorem 3 we found that the corresponding groups R(r, n, k, h) are free products of copies of F (3, 12, 4) (for (S1)), of F (3, 8, 2) (for (S2)), and of either F (3, 6, 1) or R(3, 6, 5, 2) (for (S3)). Simplifying the presentations in GAP [12] reveals that F (3, 12, 4) = x 2 , x 5 | (x 2 x 5 ) 37 ∼ = Z 37 * Z and that (writing a = x 1 …”