Consider the following premises. S_7(a_7) -> p_3. forall x_7: R_7(x_7) <-> S_7(x_7). Can we infer R_7(a_7) -> p_3 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) we can infer R_7(a_7) -> S_7(a_7). Finally, from R_7(a_7) -> S_7(a_7), S_7(a_7) -> p_3 we can infer R_7(a_7) -> p_3. Therefore, the answer is yes.