Consider the following premises. ~R_12(a_12). forall x_12: R_12(x_12) or S_12(x_12). q. Can we infer ~S_12(a_12) from them? If possible, name the inference rules being used at each step.
 From forall x_12: R_12(x_12) or S_12(x_12) we can infer R_12(a_12) or S_12(a_12) via universal instantiation. Finally, from R_12(a_12) or S_12(a_12), ~R_12(a_12) we can infer S_12(a_12) via disjunctive syllogism, which contradicts ~S_12(a_12). Therefore, the answer is no.