What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: p_9 <-> w_1. ~p_9. q_1.
~p_9 and q_1 can be inferred via the conjunction rule. q_1 and ~p_9 can be inferred via the conjunction rule. p_9 -> w_1 can be inferred via the biconditional elimination rule. w_1 -> p_9 can be inferred via the biconditional elimination rule. ~w_1 can be inferred via the biconditional elimination rule.