allPredicates :: MLN -> Set Predicate
allPredicates (MLN m) =
  Map.foldrWithKey (\k _ acc -> Set.union (F.atoms k) acc) Set.empty m
allPredicates :: MLN -> Set Predicate
allPredicates (MLN m) =
  Map.foldrWithKey (\k _ acc -> Set.union (F.atoms k) acc) Set.empty m
allPredicates (MLN m) =
  Map.foldrWithKey (\k _ acc -> Set.union (F.atoms k) acc) Set.empty m