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. w <-> t. q <-> w. ~q.
s -> t can be inferred via the biconditional elimination rule. w -> t can be inferred via the biconditional elimination rule. q -> w can be inferred via the biconditional elimination rule. t -> s can be inferred via the biconditional elimination rule. t -> w can be inferred via the biconditional elimination rule. w -> q can be inferred via the biconditional elimination rule. ~w can be inferred via the biconditional elimination rule.