fact: Definition nth {A} := fix nth_fix {n : nat} (v : t A n) {struct v} : Fin.t n -> A := match v with | nil _ => fun p => False_rect A (Fin.case0 _ p) | cons _ x m v' => fun p => match p in (Fin.t m') return t A (pred m') -> A with | Fin.F1 => fun _ => x | Fin.FS p' => fun v' => nth_fix v' p' end v' end.
imports: Arith_base