-- | computes the axiom for the congruence of the kernel of h
congruence_axs :: OpMap -> CASLFORMULA
congruence_axs om = conj
     where axs = MapSet.foldWithKey (\ name -> (:) . congruence_ax_aux name)
                 [] om
           conj = conjunct axs

{- | computes the axiom for the congruence of the kernel of h
for a single type of an operator id -}
congruence_axs :: OpMap -> CASLFORMULA
congruence_axs om = conj
     where axs = MapSet.foldWithKey (\ name -> (:) . congruence_ax_aux name)
                 [] om
           conj = conjunct axs

{- | computes the axiom for the congruence of the kernel of h
for a single type of an operator id -}
congruence_axs om = conj
     where axs = MapSet.foldWithKey (\ name -> (:) . congruence_ax_aux name)
                 [] om
           conj = conjunct axs

{- | computes the axiom for the congruence of the kernel of h
for a single type of an operator id -}