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: s <-> t. p_3 <-> t. s or p_3.
s -> t can be inferred via the biconditional elimination rule. p_3 -> t can be inferred via the biconditional elimination rule. t -> s can be inferred via the biconditional elimination rule. t -> p_3 can be inferred via the biconditional elimination rule.