What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? forall x_18: U_4(x_18) or U(x_18). exists x_18: U_4(x_18) -> Q_18(x_18). forall x_18: ~R_18(x_18). forall x_18: Q_18(x_18) -> R_18(x_18).
forall x_18: ~Q_18(x_18). exists x_18: U_4(x_18) -> R_18(x_18).