What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? w_4 -> w_2. w_2 -> q_6. q_6 -> w_2. w_2 -> w_4. ~q_6.
~w_2. w_4 -> q_6. q_6 -> w_4. w_4 <-> w_2. w_2 <-> q_6. q_6 <-> w_2. w_2 <-> w_4.