Consider the following premises. r and p. p_17 <-> w_4. ~w_4. Can we infer ~r from them? If possible, name the inference rules being used at each step.
 From p_17 <-> w_4, ~w_4 we can infer ~p_17 via biconditional elimination. Finally, from r and p we can infer r via simplification, which contradicts ~r. Therefore, the answer is no.