Consider the following premises. w -> q_13. s_3 -> w. q_13 -> r_13. p_8 -> s_3. r_13 -> w. Can we infer p_8 -> r_13 from them?
 From w -> q_13, q_13 -> r_13 we can infer w -> r_13. From p_8 -> s_3, s_3 -> w we can infer p_8 -> w. From w -> r_13, r_13 -> w we can infer w <-> r_13. From w <-> r_13 we can infer w -> r_13. Finally, from p_8 -> w, w -> r_13 we can infer p_8 -> r_13. Therefore, the answer is yes.