proposition: Lemma galNorm_eq0 a : (galNorm U V a == 0) = (a == 0).
proof: Proof. apply/idP/eqP=> [/prodf_eq0[x _] | ->]; last by rewrite galNorm0. by rewrite fmorph_eq0 => /eqP. 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)