proposition: Lemma nth_mktuple x0 (i : 'I_n) : nth x0 mktuple i = f i.
proof: Proof. by rewrite -tnth_nth tnth_mktuple. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(seq choice fintype path)