What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? forall x: T_1(x) -> U(x). forall x: ~U(x). exists x: T_1(x) or S(x). forall x: U(x) <-> T_1(x).
forall x: ~T_1(x). forall x: U(x) -> T_1(x). forall x: T_1(x) -> U(x). forall x: ~T_1(x).