module ext_changing_possession
  depends on changing_possession

  function declarations
    fluents
      basic
        abuts : spatial_entity * spatial_entity -> booleans

  axioms
    impossible occurs(X) if instance(X, transfer),
                            donor(X, D),
                            object(X, O),
                            -abuts(D, O).

    impossible occurs(X) if instance(X, deliver),
                            agent(X, A),
                            object(X, O),
                            -abuts(A, O).