What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? forall x: S_3(x) -> U_1(x). forall x: U_1(x) -> R_4(x). forall x: U_1(x) -> S_3(x). exists x: R_4(x) -> U_1(x).
forall x: S_3(x) -> R_4(x). exists x: R_4(x) -> S_3(x). forall x: S_3(x) <-> U_1(x). forall x: U_1(x) <-> S_3(x). exists x: R_4(x) <-> U_1(x). exists x: U_1(x) <-> R_4(x).