Consider the following premises. q_3. p_4 -> ~q_3. s_1. Can we infer p_4 from them? If possible, name the inference rules being used at each step.
 From q_3, s_1 we can infer q_3 and s_1 via conjunction. From q_3 and s_1 we can infer q_3 via simplification. Finally, from p_4 -> ~q_3, q_3 we can infer ~p_4 via modus tollens, which contradicts p_4. Therefore, the answer is no.