Definition recursion {A} : A -> (N -> A -> A) -> N -> A :=
peano_rect (fun _ => A).
#[global]
Instance recursion_wd {A} (Aeq : relation A) :
Proper (Aeq==>(Logic.eq==>Aeq==>Aeq)==>Logic.eq==>Aeq) recursion.

Lemma succ_pos_spec n : pos (succ_pos n) = succ n.