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: p_1 -> t. t <-> q_8. q_8 -> p_1.
q_8 -> t can be inferred via the transitivity rule. t -> q_8 can be inferred via the biconditional elimination rule. q_8 -> t can be inferred via the biconditional elimination rule.