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: ~u_3. u_3 <-> w. s. w or q_6.
~u_3 and s can be inferred via the conjunction rule. s and ~u_3 can be inferred via the conjunction rule. u_3 -> w can be inferred via the biconditional elimination rule. w -> u_3 can be inferred via the biconditional elimination rule. ~w can be inferred via the biconditional elimination rule.