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_2: U(x_2) -> R(x_2). forall x_2: R(x_2) -> T_1(x_2). forall x_2: T_1(x_2) -> R(x_2).
forall x_2: U(x_2) -> T_1(x_2) can be inferred via the universal transitivity rule. forall x_2: R(x_2) <-> T_1(x_2) can be inferred via the universal biconditional introduction rule. forall x_2: T_1(x_2) <-> R(x_2) can be inferred via the universal biconditional introduction rule.