Consider the following premises. ~r. w -> ~s. p_16 or r. ~p_16 or s. w <-> u. Can we infer u from them? If possible, name the inference rules being used at each step.
 From p_16 or r, ~p_16 or s we can infer r or s via resolution. From r or s, ~r we can infer s via disjunctive syllogism. From w -> ~s, s we can infer ~w via modus tollens. Finally, from w <-> u, ~w we can infer ~u via biconditional elimination, which contradicts u. Therefore, the answer is no.