Consider the following premises. R(a_7) -> ~u. u. forall x_7: R(x_7) <-> S_7(x_7). Can we infer ~S_7(a_7) from them?
 From forall x_7: R(x_7) <-> S_7(x_7) we can infer R(a_7) <-> S_7(a_7). From R(a_7) -> ~u, u we can infer ~R(a_7). Finally, from R(a_7) <-> S_7(a_7), ~R(a_7) we can infer ~S_7(a_7). Therefore, the answer is yes.