Consider the following premises. forall z: W(z) <-> U_2(z). ~q_15. U_2(a_18) <-> q_15. p. Can we infer ~W(a_18) from them?
 From forall z: W(z) <-> U_2(z) we can infer W(a_18) <-> U_2(a_18). From U_2(a_18) <-> q_15, ~q_15 we can infer ~U_2(a_18). Finally, from W(a_18) <-> U_2(a_18), ~U_2(a_18) we can infer ~W(a_18). Therefore, the answer is yes.