type econd =
  | Ein of string * Iset.t
  | Eand of econd list
  | Eor of econd list
  | Etrue
  | Efalse
;;
(* extended conditions *)

val possible_values : string -> econd -> Iset.t;;
val minimize_econd : econd -> econd;;

val evaluate : econd -> string -> Iset.t -> econd;;
(* calls minimize_econd *)

val pos_cond : econd -> bool;;
(* tells whether all tests are positive *)