Program Instance qpUnsized (qp : QProp) : UnsizedChecker (checker qp).
Next Obligation.
rewrite !semFmapSize !semReturnSize. apply imset_eq. reflexivity.
Qed.

Lemma semCheckableFunSize:
forall {A C} {H1 : Show A} `{H2 : Arbitrary A} {H3 : Checkable C}
(f : A -> C) (size: nat),
semCheckableSize f size <->
forall (a : A), semGenSize arbitrary size a -> semCheckableSize (f a) size.