What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? ~U(a_11) -> w. forall x: R(x) -> U(x). forall x: U(x) -> R(x). ~R(a_11).
forall x: R(x) <-> U(x). forall x: U(x) <-> R(x).