Consider the following premises. p_11 or p_4. ~p_4. ~p_11 or r_11. Can we infer ~r_11 from them? If possible, name the inference rules being used at each step.
 From p_11 or p_4, ~p_11 or r_11 we can infer p_4 or r_11 via resolution. Finally, from p_4 or r_11, ~p_4 we can infer r_11 via disjunctive syllogism, which contradicts ~r_11. Therefore, the answer is no.