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_4 <-> q_4. ~t. w <-> t. w <-> s_4.
s_4 -> q_4 can be inferred via the biconditional elimination rule. w -> t can be inferred via the biconditional elimination rule. w -> s_4 can be inferred via the biconditional elimination rule. q_4 -> s_4 can be inferred via the biconditional elimination rule. t -> w can be inferred via the biconditional elimination rule. s_4 -> w can be inferred via the biconditional elimination rule. ~w can be inferred via the biconditional elimination rule.