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 <-> w. p_8 <-> w. ~p_8. r_2 <-> t.
t -> w can be inferred via the biconditional elimination rule. p_8 -> w can be inferred via the biconditional elimination rule. r_2 -> t can be inferred via the biconditional elimination rule. w -> t can be inferred via the biconditional elimination rule. w -> p_8 can be inferred via the biconditional elimination rule. t -> r_2 can be inferred via the biconditional elimination rule. ~w can be inferred via the biconditional elimination rule.