proposition: Lemma radicalext_pradicalext (E F : {subfield L}) : pradical.-ext E F -> radical.-ext E F.
proof: Proof. case=> [[n e pw] Ee FE]; exists (ExtData e pw) => //. by apply: (tower_sub radical_pradical). 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)