Qed.

(* Specifications: *)
Lemma inj_pair2 :
forall (P:A -> Type) (p:A) (x y:P p),
existT P p x = existT P p y -> x = y.
Theorem equiv_dec_refl_left : forall a, @EquivDec.equiv_dec _ _ _ dec a a = left eq_refl.
End Classes.
Lemma inj_pair2 :
forall (P:A -> Type) (p:A) (x y:P p),
existT P p x = existT P p y -> x = y.