proposition: Lemma pradical_ext_Fadjoin (p : nat) (x : L) (E : {subfield L}) : prime p -> x ^+ p \in E -> pradical.-ext E <<E; x>>%AS.
proof: Proof. by move=> p_prime Exn; apply/rext_r/(pradical_Fadjoin p_prime Exn). Qed.
imports: HB(structures) mathcomp(all_ssreflect all_fingroup all_algebra) mathcomp(all_solvable all_field polyrcf) Abel(various classic_ext map_gal algR) Abel(char0 cyclotomic_ext real_closed_ext)