What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? forall y: Q_1(y) <-> W(y). forall y: ~S_1(y). exists y: Q_1(y) <-> S_1(y).
forall y: Q_1(y) -> W(y). exists y: Q_1(y) -> S_1(y). forall y: W(y) -> Q_1(y). exists y: S_1(y) -> Q_1(y). exists y: ~Q_1(y).