What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? forall x: ~S(x). exists x: Q_1(x) or P(x). forall x: S(x) <-> Q_1(x).
forall x: S(x) -> Q_1(x). forall x: Q_1(x) -> S(x). forall x: ~Q_1(x).