proposition: Lemma form_sign m u : '[(-1) ^+ m *: u] = '[u].
proof: Proof. by rewrite -signr_odd scaler_sign; case: odd; rewrite ?formN. Qed.
imports: HB(structures) mathcomp(all_ssreflect ssralg fingroup zmodp poly ssrnum) mathcomp(matrix mxalgebra vector falgebra ssrnum algC algnum) mathcomp(fieldext) mathcomp(vector)