Consider the following premises. u_3 -> P_6(a_5). forall x_6: P_6(x_6) -> Q_6(x_6). forall x_6: Q_6(x_6) -> R_6(x_6). Can we infer ~(u_3 -> R_6(a_5)) from them? If possible, name the inference rules being used at each step.
That contradicts the premises. Therefore the answer is no.