Consider the following premises. forall x_18: U_2(x_18). forall x_18: S(x_18) -> U_2(x_18). forall x_18: U_2(x_18) -> S(x_18). Can we infer ~w from them? If possible, name the inference rules being used at each step.
We cannot infer that from the premises. Therefore the answer is no.