What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? ~S_15(a_15). R_15(a_15) <-> u_3. forall x_15: R_15(x_15) -> S_15(x_15).
R_15(a_15) -> u_3. u_3 -> R_15(a_15).