Consider the following premises. ~U(b) or r_7. u_4 <-> q_15. forall x_11: U(x_11) or S_11(x_11). ~q_15. S_11(b) -> u_4. Can we infer ~u 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.