Consider the following premises. forall z: W(z) -> U(z). exists z: W(z) <-> S(z). forall z: ~S(z). forall z: U(z) -> W(z). Can we infer forall z: U(z) from them?
 From forall z: U(z) -> W(z), forall z: W(z) -> U(z) we can infer forall z: U(z) <-> W(z). From exists z: W(z) <-> S(z), forall z: ~S(z) we can infer exists z: ~W(z). Finally, from forall z: U(z) <-> W(z), exists z: ~W(z) we can infer exists z: ~U(z), which contradicts forall z: U(z). Therefore, the answer is no.