proposition: Lemma coprime_morphl G p : coprime #|G| p -> coprime #|f @* G| p.
proof: Proof. exact: coprime_dvdl (dvdn_morphim G). Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq div) mathcomp(choice fintype prime finset fingroup morphism) mathcomp(automorphism)