(** The radix must be greater than 1 *)
Record radix := { radix_val :> Z ; radix_prop : Zle_bool 2 radix_val = true }.

(* Specifications: *)
Theorem radix_val_inj :
forall r1 r2, radix_val r1 = radix_val r2 -> r1 = r2.
Theorem radix_val_inj :
forall r1 r2, radix_val r1 = radix_val r2 -> r1 = r2.