proposition: Lemma fmorph_primitive_root n z : n.-primitive_root (f z) = n.-primitive_root z.
proof: Proof. by congr (_ && _); apply: eq_forallb => i; rewrite fmorph_unity_root. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype bigop finset tuple) mathcomp(div ssralg countalg binomial)