Definition op_eq_dec : forall x y : op key, {x = y} + {x <> y}.Inductive exported (env_i : key -> option input) (env_o : key -> option output) :
    list (IR key) -> list (input * output) -> Prop :=
  | exported_nil : exported env_i env_o nil nil
  | exported_IO : forall k i o l tr,
                    env_i k = Some i ->
                    env_o k = Some o ->
                    exported env_i env_o l tr ->
                    exported env_i env_o (IRI k :: IRO k :: l) ((i, o) :: tr)
  | exported_IU : forall k i o l tr,
                    env_i k = Some i ->
                    exported env_i env_o l tr ->
                    exported env_i env_o (IRI k :: IRU k :: l) ((i, o) :: tr).Inductive exported (env_i : key -> option input) (env_o : key -> option output) :
    list (IR key) -> list (input * output) -> Prop :=
  | exported_nil : exported env_i env_o nil nil
  | exported_IO : forall k i o l tr,
                    env_i k = Some i ->
                    env_o k = Some o ->
                    exported env_i env_o l tr ->
                    exported env_i env_o (IRI k :: IRO k :: l) ((i, o) :: tr)
  | exported_IU : forall k i o l tr,
                    env_i k = Some i ->
                    exported env_i env_o l tr ->
                    exported env_i env_o (IRI k :: IRU k :: l) ((i, o) :: tr).Inductive exported (env_i : key -> option input) (env_o : key -> option output) :
    list (IR key) -> list (input * output) -> Prop :=
  | exported_nil : exported env_i env_o nil nil
  | exported_IO : forall k i o l tr,
                    env_i k = Some i ->
                    env_o k = Some o ->
                    exported env_i env_o l tr ->
                    exported env_i env_o (IRI k :: IRO k :: l) ((i, o) :: tr)
  | exported_IU : forall k i o l tr,
                    env_i k = Some i ->
                    exported env_i env_o l tr ->
                    exported env_i env_o (IRI k :: IRU k :: l) ((i, o) :: tr).Inductive exported (env_i : key -> option input) (env_o : key -> option output) :
    list (IR key) -> list (input * output) -> Prop :=
  | exported_nil : exported env_i env_o nil nil
  | exported_IO : forall k i o l tr,
                    env_i k = Some i ->
                    env_o k = Some o ->
                    exported env_i env_o l tr ->
                    exported env_i env_o (IRI k :: IRO k :: l) ((i, o) :: tr)
  | exported_IU : forall k i o l tr,
                    env_i k = Some i ->
                    exported env_i env_o l tr ->
                    exported env_i env_o (IRI k :: IRU k :: l) ((i, o) :: tr).

Lemma before_import_output_before_input : forall k k' tr, before (O k) (I k') (import tr) -> output_before_input (fst k) (snd k) (fst k') (snd k') tr.