Consider the following premises. forall x_1: Q_4(x_1) -> T_3(x_1). forall x_1: T_3(x_1) -> Q_4(x_1). exists x_1: T_3(x_1) -> Q_4(x_1). Can we infer forall x_1: ~(Q_4(x_1) <-> T_3(x_1)) from them?
That contradicts the premises. Therefore the answer is no.