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: t_3 <-> q_3. q <-> t_3.
t_3 -> q_3 can be inferred via the biconditional elimination rule. q -> t_3 can be inferred via the biconditional elimination rule. q_3 -> t_3 can be inferred via the biconditional elimination rule. t_3 -> q can be inferred via the biconditional elimination rule.