What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? forall y: ~S(y). exists y: S(y) <-> Q_2(y). forall y: W_1(y) <-> U(y). forall y: Q_2(y) <-> W_1(y).
forall y: W_1(y) -> U(y). forall y: Q_2(y) -> W_1(y). exists y: S(y) -> Q_2(y). forall y: U(y) -> W_1(y). forall y: W_1(y) -> Q_2(y). exists y: Q_2(y) -> S(y). exists y: ~Q_2(y).