Consider the following premises. p_3 -> ~s. w -> p_3. s and q_4. Can we infer w from them? If possible, name the inference rules being used at each step.
 From s and q_4 we can infer s via simplification. From p_3 -> ~s, s we can infer ~p_3 via modus tollens. Finally, from w -> p_3, ~p_3 we can infer ~w via modus tollens, which contradicts w. Therefore, the answer is no.