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_1 -> q_3. q_3 <-> q_16. q_3 -> q_16. q_16 -> r_1.
r_1 -> q_16 can be inferred via the transitivity rule. q_3 -> r_1 can be inferred via the transitivity rule. q_16 -> q_3 can be inferred via the transitivity rule. q_3 -> q_16 can be inferred via the biconditional elimination rule. q_16 -> q_3 can be inferred via the biconditional elimination rule.