(** An injective and surjective function is bijective.
    We need here stronger hypothesis : decidability of equality in Type. *)

Definition EqDec (A:Type) := forall x y:A, {x=y}+{x<>y}.

Lemma Injective_Surjective_Bijective : forall A B, Finite A -> EqDec B -> forall f:A->B, Injective f -> Surjective f -> Bijective f.