Consider the following premises. S_7(a_7) or t. ~R_7(a_7). forall x_7: R_7(x_7) <-> S_7(x_7). Can we infer ~t from them?
 From forall x_7: R_7(x_7) <-> S_7(x_7) we can infer R_7(a_7) <-> S_7(a_7). From R_7(a_7) <-> S_7(a_7), ~R_7(a_7) we can infer ~S_7(a_7). Finally, from S_7(a_7) or t, ~S_7(a_7) we can infer t, which contradicts ~t. Therefore, the answer is no.