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_3: P(x_3) -> ~T(x_3). forall x_3: U_1(x_3) -> P(x_3). forall x_3: P(x_3) -> U_1(x_3). forall x_3: T(x_3).
forall x_3: ~P(x_3) can be inferred via the universal modus tollens rule. forall x_3: U_1(x_3) <-> P(x_3) can be inferred via the universal biconditional introduction rule. forall x_3: P(x_3) <-> U_1(x_3) can be inferred via the universal biconditional introduction rule.