Consider the following premises. R_8(f) -> ~P(a_17). forall x_8: R_8(x_8) or S_8(x_8). forall y_2: P(y_2). Can we infer ~S_8(f) from them? If possible, name the inference rules being used at each step.
 From forall y_2: P(y_2) we can infer P(a_17) via universal instantiation. From forall x_8: R_8(x_8) or S_8(x_8) we can infer R_8(f) or S_8(f) via universal instantiation. From R_8(f) -> ~P(a_17), P(a_17) we can infer ~R_8(f) via modus tollens. Finally, from R_8(f) or S_8(f), ~R_8(f) we can infer S_8(f) via disjunctive syllogism, which contradicts ~S_8(f). Therefore, the answer is no.