proposition: Lemma cons_tuple_inj x : injective (@cons_tuple n T x).
proof: Proof. move=> [u Hu] [v Hv] [] ?; exact/val_inj. Qed.
imports: mathcomp(all_ssreflect ssralg fingroup zmodp poly ssrnum) mathcomp(matrix perm) ssr_ext ssralg_ext fdist