What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? ~u. S_9(a_9) -> u. forall x_9: R_9(x_9) <-> S_9(x_9). u -> S_9(a_9).
~S_9(a_9). forall x_9: R_9(x_9) -> S_9(x_9). forall x_9: S_9(x_9) -> R_9(x_9).