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: w_2 <-> q_13. ~q_13. s. w_2 <-> q_7.
~q_13 and s can be inferred via the conjunction rule. s and ~q_13 can be inferred via the conjunction rule. w_2 -> q_13 can be inferred via the biconditional elimination rule. w_2 -> q_7 can be inferred via the biconditional elimination rule. q_13 -> w_2 can be inferred via the biconditional elimination rule. q_7 -> w_2 can be inferred via the biconditional elimination rule. ~w_2 can be inferred via the biconditional elimination rule.