Program Instance unsizedMonotonicChecker (c : Checker) `{UnsizedChecker c} :
SizeMonotonicChecker c.
Next Obligation.
rewrite unsizedChecker. move => b Hb. by eauto.
Qed.

Lemma semShrinking_idSize {C A} {HCheck : Checkable C}
(sh : A -> list A) (x : A) (pf : A -> C) (s : nat) :
semCheckerSize (shrinking sh x pf) s <->
semCheckableSize (pf x) s.