Consider the following premises. P_7(a_7). forall x_7: ~P_7(x_7) or R_2(x_7). forall x_7: ~P_2(x_7) or R(x_7). Can we infer forall x_7: ~(R_2(x_7) or R(x_7)) from them? If possible, name the inference rules being used at each step.
That contradicts the premises. Therefore the answer is no.