proposition: Lemma cfextprodMnl h g n : g *+ n \ox h = g \ox h *+ n.
proof: Proof. Proof using. by rewrite -!cfextprodrE linearMn. 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