Consider the following premises. forall x_17: P_17(x_17) <-> Q_17(x_17). forall x_17: ~P_17(x_17). p_4 -> Q_17(a_14). Can we infer p_4 from them? If possible, name the inference rules being used at each step.
 From forall x_17: P_17(x_17) <-> Q_17(x_17), forall x_17: ~P_17(x_17) we can infer forall x_17: ~Q_17(x_17) via universal biconditional elimination. From forall x_17: ~Q_17(x_17) we can infer ~Q_17(a_14) via universal instantiation. Finally, from p_4 -> Q_17(a_14), ~Q_17(a_14) we can infer ~p_4 via modus tollens, which contradicts p_4. Therefore, the answer is no.