Consider the following premises. ~w_4. ~s. s or t_2. w_4 <-> q_22. Can we infer ~t_2 from them? If possible, name the inference rules being used at each step.
 From w_4 <-> q_22 we can infer q_22 -> w_4 via biconditional elimination. Finally, from s or t_2, ~s we can infer t_2 via disjunctive syllogism, which contradicts ~t_2. Therefore, the answer is no.