(* on_line *)

(* Specifications: *)
Lemma test_py_on_line_1 : forall I B C D E,
on_line I B C -> Py I D E = Py E D I.
Lemma test_py_on_line_2 : forall I B C D E,
on_line I B C -> Py D E I = Py D E I.
Lemma test_py_on_line_3 : forall I B C D,
on_line I B C -> Py I D I = Py I D I.
Lemma test_py_on_line_4 : forall I B C,
on_line I B C -> Py B I C = Py B I C.
Lemma test_py_on_line_4_b : forall I B C,
B<>C -> on_line I B C -> Py B I C = Py B I C.
Lemma test_py_on_line_4_c : forall I B C,
B=C -> on_line I B C -> Py B I C = Py B I C.
Lemma test_py_on_line_5 : forall I P Q B,
on_line I P Q -> Py B I B = Py B I B.