fact: Fixpoint of_nat_lt {p n : nat} : p < n -> t n := match n with |0 => fun H : p < 0 => False_rect _ (PeanoNat.Nat.nlt_0_r p H) |S n' => match p with |0 => fun _ => @F1 n' |S p' => fun H => FS (of_nat_lt (proj2 (Nat.succ_lt_mono _ _) H)) end end.
imports: PeanoNat