proposition: Lemma galois_connection_subset E (A : {set gal_of E}): A \subset 'Gal(E / fixedField A).
proof: Proof. apply/subsetP => x Ax; rewrite gal_kAut ?capvSl // kAutE limg_gal subvv andbT. by apply/kAHomP=> a /mem_fixedFieldP[_ ->]. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq div) mathcomp(choice fintype tuple finfun bigop ssralg poly) mathcomp(polydiv finset fingroup morphism quotient perm) mathcomp(action zmodp cyclic matrix mxalgebra vector) mathcomp(falgebra fieldext separable)