module ext_admitting_and_shutting_out
  depends on admitting_and_shutting_out

  function declarations
    fluents 
      basic
        contained_in : tangible_entity * tangible_entity -> booleans

  axioms
    impossible occurs(X) if instance(X, shut_out),
                            object(X, O),
                            base(X, B),
                            contained_in(O, B).