What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? r_4 <-> u_1. forall x_12: R_12(x_12) <-> S_12(x_12). ~R_12(a_12). u_1 <-> S_12(a_12).
r_4 -> u_1. u_1 -> S_12(a_12). u_1 -> r_4. S_12(a_12) -> u_1. forall x_12: R_12(x_12) -> S_12(x_12). forall x_12: S_12(x_12) -> R_12(x_12).