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 -> t. r <-> w_3. t -> r.
w_3 -> r can be inferred via the transitivity rule. r -> w_3 can be inferred via the biconditional elimination rule. w_3 -> r can be inferred via the biconditional elimination rule.