Consider the following premises. q_3. q_1 -> p_11. p_11 -> ~q_3. Can we infer q_1 from them? If possible, name the inference rules being used at each step.
 From p_11 -> ~q_3, q_3 we can infer ~p_11 via modus tollens. Finally, from q_1 -> p_11, ~p_11 we can infer ~q_1 via modus tollens, which contradicts q_1. Therefore, the answer is no.