What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? ~u. u <-> t_3. t_3 <-> S_15(a_15). forall x_15: R_15(x_15) -> S_15(x_15).
u -> t_3. t_3 -> S_15(a_15). t_3 -> u. S_15(a_15) -> t_3. ~t_3.