Consider the following premises. s_2. s_2 <-> p_1. p_12 -> ~q_12. q_12. Can we infer p_1 and ~p_12 from them? If possible, name the inference rules being used at each step.
 From s_2 <-> p_1 we can infer s_2 -> p_1 via biconditional elimination. From p_12 -> ~q_12, q_12 we can infer ~p_12 via modus tollens. From s_2 -> p_1, s_2 we can infer p_1 via modus ponens. Finally, from p_1, ~p_12 we can infer p_1 and ~p_12 via conjunction. Therefore, the answer is yes.