Consider the following premises. forall x_13: P_13(x_13) -> Q_13(x_13). forall x_13: Q_13(x_13) -> P_13(x_13). P_13(f_3) or ~r. Can we infer ~(r -> Q_13(f_3)) from them? If possible, name the inference rules being used at each step.
That contradicts the premises. Therefore the answer is no.