Consider the following premises. exists x_13: P_6(x_13) -> Q_3(x_13). forall x_13: P_13(x_13) -> Q_3(x_13). forall x_13: Q_3(x_13) -> P_13(x_13). forall x_13: P_6(x_13) or ~P_13(x_13). Can we infer forall x_13: ~(Q_3(x_13) <-> P_6(x_13)) from them? If possible, name the inference rules being used at each step.
That contradicts the premises. Therefore the answer is no.