What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? exists y: Q_4(y) -> T(y). forall y: Q_4(y) or R_4(y). forall y: T(y) -> Q_4(y). forall y: R_4(y) -> T(y).
forall y: R_4(y) -> Q_4(y). exists y: T(y). exists y: Q_4(y) <-> T(y). exists y: T(y) <-> Q_4(y).