Consider the following premises. s_1 -> ~q_15. forall x_25: ~R_25(x_25). q_1. R_25(a_25) or q_15. Can we infer s_1 from them? If possible, name the inference rules being used at each step.
 From forall x_25: ~R_25(x_25) we can infer ~R_25(a_25) via universal instantiation. From R_25(a_25) or q_15, ~R_25(a_25) we can infer q_15 via disjunctive syllogism. Finally, from s_1 -> ~q_15, q_15 we can infer ~s_1 via modus tollens, which contradicts s_1. Therefore, the answer is no.