Consider the following premises. exists x_6: U(x_6) and Q_6(x_6). Can we infer forall x_6: ~(U(x_6) or Q(x_6)) from them? If possible, name the inference rules being used at each step.
 From exists x_6: U(x_6) and Q_6(x_6) we can infer exists x_6: U(x_6) via existential simplification. Finally, from exists x_6: U(x_6) we can infer exists x_6: U(x_6) or Q(x_6) via existential addition, which contradicts forall x_6: ~(U(x_6) or Q(x_6)). Therefore, the answer is no.