Consider the following premises. R_6(a_5) -> p_4. forall x_6: P_6(x_6) -> Q_6(x_6). forall x_6: Q_6(x_6) -> R_6(x_6). Can we infer P_6(a_5) -> p_4 from them? If possible, name the inference rules being used at each step.
 From forall x_6: P_6(x_6) -> Q_6(x_6), forall x_6: Q_6(x_6) -> R_6(x_6) we can infer forall x_6: P_6(x_6) -> R_6(x_6) via universal transitivity. From forall x_6: P_6(x_6) -> R_6(x_6) we can infer P_6(a_5) -> R_6(a_5) via universal instantiation. Finally, from P_6(a_5) -> R_6(a_5), R_6(a_5) -> p_4 we can infer P_6(a_5) -> p_4 via transitivity. Therefore, the answer is yes.