Consider the following premises. ~R_12(a_12). w -> ~S_12(a_12). forall x_12: R_12(x_12) or S_12(x_12). Can we infer ~w from them?
 From forall x_12: R_12(x_12) or S_12(x_12) we can infer R_12(a_12) or S_12(a_12). From R_12(a_12) or S_12(a_12), ~R_12(a_12) we can infer S_12(a_12). Finally, from w -> ~S_12(a_12), S_12(a_12) we can infer ~w. Therefore, the answer is yes.