proposition: Lemma cfextprodNl h g : - g \ox h = - g \ox h.
proof: Proof. Proof using. by rewrite -!cfextprodrE linearN. Qed.
imports: HB(structures) mathcomp(all_ssreflect) mathcomp(ssralg fingroup morphism perm gproduct) mathcomp(ssrnum matrix vector mxalgebra algC) mathcomp(classfun character mxrepresentation) tools ordcast partition sorted permcomp cycles cycletype permcent