Require Export A6_Intersection.
Section SUPERIMPOSED_EQUIVALENCE.

(* Specifications: *)
Lemma SuperimposedRefl : forall F : Figure,
Superimposed F F.
Lemma SuperimposedSym : forall F1 F2 : Figure,
Superimposed F1 F2 -> Superimposed F2 F1.
Lemma SuperimposedTrans : forall F1 F2 F3 : Figure,
Superimposed F1 F2 -> Superimposed F2 F3 -> Superimposed F1 F3.
Lemma SuperimposedHalfLines : forall A B C : Point,
A <> B ->
HalfLine A B C ->
Superimposed (HalfLine A B) (HalfLine A C).