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 <-> q_9. q_4 -> t. q_4 <-> q_14. ~q_9.
t -> q_9 can be inferred via the biconditional elimination rule. q_4 -> q_14 can be inferred via the biconditional elimination rule. q_9 -> t can be inferred via the biconditional elimination rule. q_14 -> q_4 can be inferred via the biconditional elimination rule. ~t can be inferred via the biconditional elimination rule.