What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? R_20(a_20) <-> q. S_20(a_20) <-> r. forall x_20: R_20(x_20) -> S_20(x_20).
R_20(a_20) -> q. S_20(a_20) -> r. q -> R_20(a_20). r -> S_20(a_20).