Consider the following premises. ~r. s <-> r. s <-> R_7(a_7). forall x_7: R_7(x_7) <-> S_7(x_7). Can we infer ~S_7(a_7) from them?
 From s <-> r, ~r we can infer ~s. From forall x_7: R_7(x_7) <-> S_7(x_7) we can infer R_7(a_7) <-> S_7(a_7). From s <-> R_7(a_7), ~s we can infer ~R_7(a_7). Finally, from R_7(a_7) <-> S_7(a_7), ~R_7(a_7) we can infer ~S_7(a_7). Therefore, the answer is yes.