Module Type KNOT__COCONTRAVARIANT_HERED_T_OTH_REL.
Declare Module KI: KNOT_INPUT__COCONTRAVARIANT_HERED_T_OTH_REL.
Parameter knot:Type.
Parameter ageable_knot : ageable knot.
Existing Instance ageable_knot.
Parameter hered : (knot * other -> T) -> Prop.
Definition predicate := { p:knot * other -> T | hered p }.
Parameter squash : (nat * F predicate predicate) -> knot.
Parameter unsquash : knot -> (nat * F predicate predicate).
Parameter approx : nat -> predicate -> predicate.

Axiom squash_unsquash : forall k:knot, squash (unsquash k) = k.
Axiom unsquash_squash : forall (n:nat) (f:F predicate predicate),
unsquash (squash (n,f)) = (n, fmap F (approx n) (approx n) f).