Consider the following premises. forall z: S_1(z) or ~R(z). forall z: S_1(z) <-> R(z). Can we infer forall z: R(z) -> S_1(z) from them?
 From forall z: S_1(z) <-> R(z) we can infer forall z: S_1(z) -> R(z). Finally, from forall z: S_1(z) or ~R(z) we can infer forall z: R(z) -> S_1(z). Therefore, the answer is yes.