Instance forAllMonotonic {A C} {_ : Checkable C} `{Show A} (g : G A) (f : A -> C)
        `{SizeMonotonic _ g} `{forall x, SizeMonotonicChecker (checker (f x))} :
  SizeMonotonicChecker (forAll g f).

Lemma semCheckableBoolSize (b : bool) size : semCheckableSize b size <-> b.