What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? forall y: U(y) -> R_1(y). forall y: R_1(y) -> P(y). exists y: P(y) -> S(y). forall y: S(y) -> U(y).
forall y: U(y) -> P(y). forall y: S(y) -> R_1(y). exists y: P(y) -> U(y). exists y: R_1(y) -> S(y).