Definition L_term := rho (.\ "L", "n";
"n" !Nil (.\ "n"; !Append ("L" "n") (!Cons (!Var "n") (!Append (!Map_pro !App ("L" "n") ("L" "n")) (!Map !Lam ("L" "n")))))).

Lemma L_term_correct n : L_term (enc n) ≡ lenc tenc (L n).
Definition OfNat : term := .\ "n" ; !Nth "n" (!L_term (!Succ ("n"))).