What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? forall y: ~T_2(y). forall y: T(y) or U(y). exists y: ~T(y) or U_1(y). forall y: U(y) <-> T_2(y).
exists y: U(y) or U_1(y). forall y: U(y) -> T_2(y). forall y: T_2(y) -> U(y). forall y: ~U(y).