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_6 -> w. r <-> w. t -> r_6. r -> t.
t -> w can be inferred via the transitivity rule. r -> r_6 can be inferred via the transitivity rule. r -> w can be inferred via the biconditional elimination rule. w -> r can be inferred via the biconditional elimination rule.