| C.Cast (te,ty) -> C.Cast (um_aux te, um_aux ty)
| C.Prod (n,s,t) -> C.Prod (n, um_aux s, um_aux t)
| C.Lambda (n,s,t) -> C.Lambda (n, um_aux s, um_aux t)
| C.Cast (te,ty) -> C.Cast (um_aux te, um_aux ty)
| C.Prod (n,s,t) -> C.Prod (n, um_aux s, um_aux t)
| C.Lambda (n,s,t) -> C.Lambda (n, um_aux s, um_aux t)