Consider the following premises. q_8 -> r_8. w -> q_8. r_8 -> w. r_3 -> w. Can we infer ~(r_3 -> r_8) from them?
 From w -> q_8, q_8 -> r_8 we can infer w -> r_8. From r_8 -> w, w -> r_8 we can infer r_8 <-> w. From r_8 <-> w we can infer w -> r_8. Finally, from r_3 -> w, w -> r_8 we can infer r_3 -> r_8, which contradicts ~(r_3 -> r_8). Therefore, the answer is no.