simple induction E1; intros A1 f1 HR1; simple induction E2;
intros A2 f2 HR2 E p1 p2.
simple induction 1; intros o1 o2.
split.
intros a2 i2.
elim (IN_EXType _ _ i2).
intros x e.
change (Ord (f2 a2)) in |- *.
apply Ord_sound with (pi2 E x).
auto with zfc.
cut (IN (pi2 E x) (sup A1 f1)).
simple induction 1; intros a1 e1.
apply Ord_sound with (f1 a1); auto with zfc.
unfold Ord in |- *; apply o1.
apply IN_sound_left with (pi2 E x); auto with zfc.
apply IN_sound_left with (f2 a2); auto with zfc.
unfold INC in p1; apply p1; auto with zfc.
apply IN_sound_left with (f2 a2); auto with zfc.
intros a2 e i inc o.
elim (IN_EXType _ _ i).
intros x e2.
cut (IN (pi2 E x) (sup A1 f1)).
simple induction 1; intros a1 e1.
cut (INC e (f1 a1)).
intros inc1.
apply (o2 a1) with (p := inc1).
apply IN_sound_left with (pi2 E x).
auto with zfc.
apply IN_sound_left with (f2 a2); auto with zfc.
elim (ord_sound (f1 a1) (f2 a2)) with (p := inc1) (p' := inc).
intros h1 h2.
auto with zfc.
apply EQ_tran with (pi2 E x).
auto with zfc.
auto with zfc.
auto with zfc.
apply INC_sound_right with (pi2 E x).
auto with zfc.
apply INC_sound_right with (f2 a2); auto with zfc.
apply IN_sound_left with (f2 a2); auto with zfc.
Qed.

Lemma plump :
forall E : Ens,
Ord E ->
forall E1 E2 : Ens, Ord E1 -> Ord E2 -> IN E1 E -> INC E2 E1 -> IN E2 E.