What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? r_4 <-> t. w <-> u. w <-> w_3. w_3 <-> t. ~r_4.
r_4 -> t. w -> u. w -> w_3. w_3 -> t. t -> r_4. u -> w. w_3 -> w. t -> w_3. ~t.