| C.Cast (te,ty) -> C.Cast (aux n te, aux n ty)
| C.Prod (nn,s,t) -> C.Prod (nn, aux n s, aux (n+1) t)
| C.Lambda (nn,s,t) -> C.Lambda (nn, aux n s, aux (n+1) t)
| C.Cast (te,ty) -> C.Cast (aux n te, aux n ty)
| C.Prod (nn,s,t) -> C.Prod (nn, aux n s, aux (n+1) t)
| C.Lambda (nn,s,t) -> C.Lambda (nn, aux n s, aux (n+1) t)