Consider the following premises. p -> R_15(a_15). S_15(a_15) <-> q_9. forall x_15: R_15(x_15) -> S_15(x_15). p or q_9. Can we infer S_15(a_15) from them? If possible, name the inference rules being used at each step.
 From forall x_15: R_15(x_15) -> S_15(x_15) we can infer R_15(a_15) -> S_15(a_15) via universal instantiation. From S_15(a_15) <-> q_9 we can infer q_9 -> S_15(a_15) via biconditional elimination. From p -> R_15(a_15), R_15(a_15) -> S_15(a_15) we can infer p -> S_15(a_15) via transitivity. Finally, from p -> S_15(a_15), q_9 -> S_15(a_15), p or q_9 we can infer S_15(a_15) via disjunction elimination. Therefore, the answer is yes.