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_3 <-> q_17. p_4 <-> q_17. p_4 or r_3.
r_3 -> q_17 can be inferred via the biconditional elimination rule. p_4 -> q_17 can be inferred via the biconditional elimination rule. q_17 -> r_3 can be inferred via the biconditional elimination rule. q_17 -> p_4 can be inferred via the biconditional elimination rule.