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 -> t_2. w <-> t_2. t_2 -> w.
w <-> t_2 can be inferred via the biconditional introduction rule. t_2 <-> w can be inferred via the biconditional introduction rule. w -> t_2 can be inferred via the biconditional elimination rule. t_2 -> w can be inferred via the biconditional elimination rule.