Consider the following premises. p -> w_2. p. w_2 -> w_1. Can we infer w_1 from them? If possible, name the inference rules being used at each step.
 From p -> w_2, w_2 -> w_1 we can infer p -> w_1 via transitivity. Finally, from p -> w_1, p we can infer w_1 via modus ponens. Therefore, the answer is yes.