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_8 <-> r. r -> s. s -> p_8.
r -> p_8 can be inferred via the transitivity rule. p_8 -> r can be inferred via the biconditional elimination rule. r -> p_8 can be inferred via the biconditional elimination rule.