What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: forall x: U(x) -> Q_2(x). forall x: Q_2(x) -> R(x). forall x: R(x) -> Q_2(x).
forall x: U(x) -> R(x) can be inferred via the universal transitivity rule. forall x: Q_2(x) <-> R(x) can be inferred via the universal biconditional introduction rule. forall x: R(x) <-> Q_2(x) can be inferred via the universal biconditional introduction rule.