Consider the following premises. p_7 or ~R(a). forall x_12: R(x_12) <-> S_12(x_12). ~p_7. Can we infer ~S_12(a) from them?
 From forall x_12: R(x_12) <-> S_12(x_12) we can infer R(a) <-> S_12(a). From p_7 or ~R(a) we can infer R(a) -> p_7. From R(a) -> p_7, ~p_7 we can infer ~R(a). Finally, from R(a) <-> S_12(a), ~R(a) we can infer ~S_12(a). Therefore, the answer is yes.