Consider the following premises. w_4 -> r_1. r_1 -> t. s_3 -> w_4. Can we infer s_3 -> t from them? If possible, name the inference rules being used at each step.
 From s_3 -> w_4, w_4 -> r_1 we can infer s_3 -> r_1 via transitivity. Finally, from s_3 -> r_1, r_1 -> t we can infer s_3 -> t via transitivity. Therefore, the answer is yes.