Definition Rnd_NG_pt_unicity_prop F P :=
  forall x d u,
  Rnd_DN_pt F x d -> Rnd_N_pt F x d ->
  Rnd_UP_pt F x u -> Rnd_N_pt F x u ->
  P x d -> P x u -> d = u.

Theorem Rnd_NG_pt_unicity : forall (F : R -> Prop) (P : R -> R -> Prop), Rnd_NG_pt_unicity_prop F P -> forall x f1 f2 : R, Rnd_NG_pt F P x f1 -> Rnd_NG_pt F P x f2 -> f1 = f2.