Set Implicit Arguments.
Unset Strict Implicit.
Require Export point_angle.

(* Specifications: *)
Lemma calcul4 :
forall a b c d : AV,
R (plus (plus a b) (plus c d)) (plus (plus a c) (plus b d)).
Lemma calcul4 :
forall a b c d : AV,
R (plus (plus a b) (plus c d)) (plus (plus a c) (plus b d)).