What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? t_3 or U(a). forall y_2: Q(y_2) <-> U(y_2). ~Q(a).
~U(a) -> t_3. forall y_2: Q(y_2) -> U(y_2). forall y_2: U(y_2) -> Q(y_2).