Consider the following premises. forall x_9: R_9(x_9) <-> S_9(x_9). R_9(c) -> S_9(c). Can we infer S_9(c) -> R_9(c) from them?
 From forall x_9: R_9(x_9) <-> S_9(x_9) we can infer R_9(c) <-> S_9(c). Finally, from R_9(c) <-> S_9(c) we can infer S_9(c) -> R_9(c). Therefore, the answer is yes.