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: u <-> q_8. u <-> q_4.
u -> q_8 can be inferred via the biconditional elimination rule. u -> q_4 can be inferred via the biconditional elimination rule. q_8 -> u can be inferred via the biconditional elimination rule. q_4 -> u can be inferred via the biconditional elimination rule.