Consider the following premises. R_12(a_12) or q_1. forall x_12: R_12(x_12) <-> S_12(x_12). q_1 <-> S_12(a_12). Can we infer ~S_12(a_12) from them?
 From forall x_12: R_12(x_12) <-> S_12(x_12) we can infer R_12(a_12) <-> S_12(a_12). From R_12(a_12) <-> S_12(a_12) we can infer R_12(a_12) -> S_12(a_12). From q_1 <-> S_12(a_12) we can infer q_1 -> S_12(a_12). Finally, from R_12(a_12) -> S_12(a_12), q_1 -> S_12(a_12), R_12(a_12) or q_1 we can infer S_12(a_12), which contradicts ~S_12(a_12). Therefore, the answer is no.