如何使Coq中模块签名之外的符号可见？

我在Coq中定义了一个模块签名，它定义了几个符号。然而，当我尝试在签名之外使用这些符号时，Coq失败了。下面给出了我的代码的简化版本。任何帮助都将不胜感激

Module Type Field_Axioms.

  Delimit Scope Field_scope with F.
  Open Scope Field_scope.

  Parameter Element : Set.

  Parameter addition : Element -> Element -> Element.

  Infix " + " := addition : Field_scope. (* ASSIGNS THE "+" OPERATOR TO SCOPE. *)

End Field_Axioms

Module Type Ordered_Field_Axioms.

  Declare Module Field : Field_Axioms.

  Print Scope Field_scope. (* SHOWS THAT THE SCOPE IS EMPTY. *)

End Ordered_Field_Axioms.

您可以替换：

Declare Module Field : Field_Axioms.

与：

Declare Module Import Field : Field_Axioms.