Consider the following premises. forall x_8: P_4(x_8) or Q_8(x_8). forall x_8: P_4(x_8) -> U_2(x_8). forall x_8: U_2(x_8) <-> Q_8(x_8). Can we infer exists x_8: ~(U_2(x_8) or P(x_8)) from them?
 From forall x_8: U_2(x_8) <-> Q_8(x_8) we can infer forall x_8: Q_8(x_8) -> U_2(x_8). From forall x_8: P_4(x_8) -> U_2(x_8), forall x_8: Q_8(x_8) -> U_2(x_8), forall x_8: P_4(x_8) or Q_8(x_8) we can infer forall x_8: U_2(x_8). Finally, from forall x_8: U_2(x_8) we can infer forall x_8: U_2(x_8) or P(x_8), which contradicts exists x_8: ~(U_2(x_8) or P(x_8)). Therefore, the answer is no.