Consider the following premises. q_8. ~p <-> t_4. p -> ~q_8. Can we infer ~t_4 from them? If possible, name the inference rules being used at each step.
 From p -> ~q_8, q_8 we can infer ~p via modus tollens. From ~p <-> t_4 we can infer ~p -> t_4 via biconditional elimination. Finally, from ~p -> t_4, ~p we can infer t_4 via modus ponens, which contradicts ~t_4. Therefore, the answer is no.