hom_surjectivity :: Set.Set SORT -> [Named CASLFORMULA]
hom_surjectivity = Set.fold f []
      where f x = (sort_surj x :)

-- | generates the formula to state the homomorphism is surjective
hom_surjectivity :: Set.Set SORT -> [Named CASLFORMULA]
hom_surjectivity = Set.fold f []
      where f x = (sort_surj x :)

-- | generates the formula to state the homomorphism is surjective
hom_surjectivity = Set.fold f []
      where f x = (sort_surj x :)

-- | generates the formula to state the homomorphism is surjective