What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? r. forall x_21: ~R_21(x_21). S(a_16) <-> R_21(a_1). forall x_16: S(x_16) <-> S_16(x_16).
S(a_16) -> R_21(a_1). R_21(a_1) -> S(a_16). forall x_16: S(x_16) -> S_16(x_16). forall x_16: S_16(x_16) -> S(x_16).