-- | computes the transitivity axioms for the kernel of h
transitivity_axs :: Set.Set SORT -> CASLFORMULA
transitivity_axs ss = conj
     where axs = Set.fold ((:) . transitivity_ax) [] ss
           conj = conjunct axs
transitivity_axs :: Set.Set SORT -> CASLFORMULA
transitivity_axs ss = conj
     where axs = Set.fold ((:) . transitivity_ax) [] ss
           conj = conjunct axs
transitivity_axs ss = conj
     where axs = Set.fold ((:) . transitivity_ax) [] ss
           conj = conjunct axs