Inductive Approximant (A X:Ensemble U) : Prop :=
    Defn_of_Approximant : Finite U X -> Included U X A -> Approximant A X.Inductive Approximant (A X:Ensemble U) : Prop :=
    Defn_of_Approximant : Finite U X -> Included U X A -> Approximant A X.

Theorem Pigeonhole_bis : forall (A:Ensemble U) (f:U -> V), ~ Finite U A -> Finite V (Im U V A f) -> ~ injective U V f.