Consider the following premises. ~q_6. p_1 -> w. w -> q_6. p <-> p_1. Can we infer p from them? If possible, name the inference rules being used at each step.
 From w -> q_6, ~q_6 we can infer ~w via modus tollens. From p_1 -> w, ~w we can infer ~p_1 via modus tollens. Finally, from p <-> p_1, ~p_1 we can infer ~p via biconditional elimination, which contradicts p. Therefore, the answer is no.