Module Type KNOT__COVARIANT_HERED_PROP_OTH_REL.
Declare Module KI : KNOT_INPUT__COVARIANT_HERED_PROP_OTH_REL.
Parameter knot : Type.
Parameter ageable_knot : ageable knot.
Existing Instance ageable_knot.
Definition ag_knot_other := ag_prod knot other ageable_knot.
Existing Instance ag_knot_other.
Parameter expandM : @modality (knot * other) ag_knot_other.
Definition assert := { p:pred (knot * other) | boxy expandM p }.
Parameter squash : (nat * F assert) -> knot.
Parameter unsquash : knot -> (nat * F assert).
Parameter approx : nat -> assert -> assert.

Axiom approx_spec : forall n p k,
proj1_sig (approx n p) k = (level (fst k) < n /\ proj1_sig p k).