Consider the following premises. ~r_4. p_13 <-> r_4. p_13 <-> r_1. p_4. Can we infer ~r_1 and p_4 from them?
 From p_13 <-> r_4, ~r_4 we can infer ~p_13. From p_13 <-> r_1, ~p_13 we can infer ~r_1. Finally, from ~r_1, p_4 we can infer ~r_1 and p_4. Therefore, the answer is yes.