Definition codeArityLNNR (r : nat) := switchPR r 0 3.

(* Specifications: *)
Lemma codeArityLNNRIsPR : isPR 1 codeArityLNNR.
Lemma codeArityLNNRIsCorrect1 :
forall r : Relations LNN,
codeArityLNNR (codeLNNRelation r) = S (arity LNN (inl _ r)).
Lemma codeArityLNNRIsCorrect2 :
forall n : nat,
codeArityLNNR n <> 0 -> exists r : Relations LNN, codeLNNRelation r = n.