(* Fix arity *)\r
let open Num in\r
let rec aux lev : nf -> nf = function\r
- | `I((n,_), args) -> `I((n,1 + Listx.length args), Listx.map (fun t -> aux lev t) args)\r
+ | `I((n,_), args) -> `I((n,(if lev = 0 then 0 else 1) + Listx.length args), Listx.map (aux lev) args)\r
| `Var(n,_) -> fix lev n\r
| `Lam(_,t) -> `Lam (true, aux (lev+1) t)\r
| `Match _ | `N _ -> assert false in\r