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: r_2 <-> w_4. p_16 -> r_2. p_16 or q_9. ~w_4. p_4 <-> q_9.
r_2 -> w_4 can be inferred via the biconditional elimination rule. p_4 -> q_9 can be inferred via the biconditional elimination rule. w_4 -> r_2 can be inferred via the biconditional elimination rule. q_9 -> p_4 can be inferred via the biconditional elimination rule. ~r_2 can be inferred via the biconditional elimination rule.