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 <-> p_9. p_9 <-> t. ~t. p -> q.
q -> p_9 can be inferred via the biconditional elimination rule. p_9 -> t can be inferred via the biconditional elimination rule. p_9 -> q can be inferred via the biconditional elimination rule. t -> p_9 can be inferred via the biconditional elimination rule. ~p_9 can be inferred via the biconditional elimination rule.