Consider the following premises. P_7(h_2) -> Q_7(h_2). forall x_7: P_7(x_7) or ~Q_7(x_7). Can we infer ~(P_7(h_2) <-> Q_7(h_2)) from them? If possible, name the inference rules being used at each step.
 From forall x_7: P_7(x_7) or ~Q_7(x_7) we can infer forall x_7: Q_7(x_7) -> P_7(x_7) via universal rewriting. From forall x_7: Q_7(x_7) -> P_7(x_7) we can infer Q_7(h_2) -> P_7(h_2) via universal instantiation. Finally, from P_7(h_2) -> Q_7(h_2), Q_7(h_2) -> P_7(h_2) we can infer P_7(h_2) <-> Q_7(h_2) via biconditional introduction, which contradicts ~(P_7(h_2) <-> Q_7(h_2)). Therefore, the answer is no.