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_3 -> r_1. q_9. q_3 <-> q_9.
q_3 -> q_9 can be inferred via the biconditional elimination rule. q_9 -> q_3 can be inferred via the biconditional elimination rule.