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: q <-> r_8. q -> r. r -> r_8.
q -> r_8 can be inferred via the transitivity rule. q -> r_8 can be inferred via the biconditional elimination rule. r_8 -> q can be inferred via the biconditional elimination rule.