Consider the following premises. w -> q_7. p_7 or ~q_7. p_7 -> w. Can we infer w <-> p_7 from them? If possible, name the inference rules being used at each step.
 From p_7 or ~q_7 we can infer q_7 -> p_7 via rewriting. From w -> q_7, q_7 -> p_7 we can infer w -> p_7 via transitivity. Finally, from w -> p_7, p_7 -> w we can infer w <-> p_7 via biconditional introduction. Therefore, the answer is yes.