proposition: Lemma tuple_map_ord U (t : n.-tuple U) : t = [tuple of map (tnth t) ord_tuple].
proof: Proof. by apply: val_inj => /=; rewrite map_tnth_enum. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(seq choice fintype path)