Inductive JMeq (A:Type) (x:A) : forall B:Type, B -> Prop :=
    JMeq_refl : JMeq x x.Inductive JMeq (A:Type) (x:A) : forall B:Type, B -> Prop :=
    JMeq_refl : JMeq x x.Definition JMeq_hom {A : Type} (x y : A) := JMeq x y.

Lemma JMeq_eq_dep : forall U (P:U->Type) p q (x:P p) (y:P q), p = q -> JMeq x y -> eq_dep U P p x q y.