(* given the reference of an inductive type, returns the i-th contructor *)
val mk_constructor: int -> reference -> reference
val mk_fix: int -> int -> reference -> reference
val mk_cofix: int -> reference -> reference
(* given the reference of an inductive type, returns the i-th contructor *)
val mk_constructor: int -> reference -> reference
val mk_fix: int -> int -> reference -> reference
val mk_cofix: int -> reference -> reference