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_3. w_3 or q_13. t <-> u_3. u_3.
q_13 can be inferred via the disjunctive syllogism rule. ~w_3 and u_3 can be inferred via the conjunction rule. u_3 and ~w_3 can be inferred via the conjunction rule. t -> u_3 can be inferred via the biconditional elimination rule. u_3 -> t can be inferred via the biconditional elimination rule.