Consider the following premises. ~R_6(a_6) or w. ~S_6(a_6). forall x_6: R_6(x_6) or S_6(x_6). Can we infer ~w from them?
 From forall x_6: R_6(x_6) or S_6(x_6) we can infer R_6(a_6) or S_6(a_6). From R_6(a_6) or S_6(a_6), ~R_6(a_6) or w we can infer S_6(a_6) or w. Finally, from S_6(a_6) or w, ~S_6(a_6) we can infer w, which contradicts ~w. Therefore, the answer is no.