Consider the following premises. ~s_3. forall x_8: R_8(x_8) or S_8(x_8). s_3 <-> R_8(a_8). Can we infer S_8(a_8) from them? If possible, name the inference rules being used at each step.
 From forall x_8: R_8(x_8) or S_8(x_8) we can infer R_8(a_8) or S_8(a_8) via universal instantiation. From s_3 <-> R_8(a_8), ~s_3 we can infer ~R_8(a_8) via biconditional elimination. Finally, from R_8(a_8) or S_8(a_8), ~R_8(a_8) we can infer S_8(a_8) via disjunctive syllogism. Therefore, the answer is yes.