Consider the following premises. forall x_5: Q_4(x_5) -> W_2(x_5). forall x_5: W_2(x_5) -> Q_5(x_5). exists x_5: T_3(x_5) -> Q_4(x_5). forall x_5: Q_5(x_5) -> T_3(x_5). Can we infer forall x_5: ~(Q_4(x_5) <-> T_3(x_5)) from them?
 From forall x_5: W_2(x_5) -> Q_5(x_5), forall x_5: Q_5(x_5) -> T_3(x_5) we can infer forall x_5: W_2(x_5) -> T_3(x_5). From forall x_5: Q_4(x_5) -> W_2(x_5), forall x_5: W_2(x_5) -> T_3(x_5) we can infer forall x_5: Q_4(x_5) -> T_3(x_5). Finally, from forall x_5: Q_4(x_5) -> T_3(x_5), exists x_5: T_3(x_5) -> Q_4(x_5) we can infer exists x_5: Q_4(x_5) <-> T_3(x_5), which contradicts forall x_5: ~(Q_4(x_5) <-> T_3(x_5)). Therefore, the answer is no.