What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? t -> u_4. u_4 <-> q_3. ~q_3. q_3 -> u_4. u_4 -> t.
q_3 -> t. t <-> u_4. u_4 <-> t. u_4 -> q_3. q_3 -> u_4. ~u_4.