Require Export Coq.Lists.List.
Require Vector.
Definition codeLength : nat -> nat :=
evalStrongRec 0
(fun n Hrecs : nat =>
switchPR n (S (codeNth (n - S (cPairPi2 (pred n))) Hrecs)) 0).

Lemma codeNoDupCorrect :
forall l : list nat,
codeNoDup (codeList l) = codeList (no_dup _ eq_nat_dec l).