proposition: Lemma rext_refl r (E : {subfield L}) : r.-ext E E.
proof: Proof. by exists trivExt; rewrite ?Fadjoin_nil//=; apply/towerP => -[]. 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)