Section equatesLemma.
Variables (A0 A1 : Type).
Variables (A2 : forall (x1 : A1), Type).
Variables (A3 : forall (x1 : A1) (x2 : A2 x1), Type).
Variables (A4 : forall (x1 : A1) (x2 : A2 x1) (x3 : A3 x2), Type).
Variables (A5 : forall (x1 : A1) (x2 : A2 x1) (x3 : A3 x2) (x4 : A4 x3), Type).
Variables (A6 : forall (x1 : A1) (x2 : A2 x1) (x3 : A3 x2) (x4 : A4 x3) (x5 : A5 x4), Type).
Proof using. intros. subst. auto. Qed.
Proof using. intros. subst. auto. Qed.
Proof using. intros. subst. auto. Qed.

Lemma equates_3 :
forall y1 (P:A0->forall(x1:A1)(x2:A2 x1),Prop) x1 x2 x3,
P y1 x2 x3 -> x1 = y1 -> P x1 x2 x3.