Consider the following premises. s -> S(a_5). forall x_12: S(x_12) -> ~U_2(x_12). forall x_12: U_2(x_12) and Q_12(x_12). Can we infer s from them? If possible, name the inference rules being used at each step.
 From forall x_12: U_2(x_12) and Q_12(x_12) we can infer forall x_12: U_2(x_12) via universal simplification. From forall x_12: S(x_12) -> ~U_2(x_12), forall x_12: U_2(x_12) we can infer forall x_12: ~S(x_12) via universal modus tollens. From forall x_12: ~S(x_12) we can infer ~S(a_5) via universal instantiation. Finally, from s -> S(a_5), ~S(a_5) we can infer ~s via modus tollens, which contradicts s. Therefore, the answer is no.