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_18: P(x_18) -> T(x_18). forall x_18: T(x_18). forall x_18: T(x_18) -> P(x_18).
forall x_18: P(x_18) can be inferred via the universal modus ponens rule. forall x_18: P(x_18) <-> T(x_18) can be inferred via the universal biconditional introduction rule. forall x_18: T(x_18) <-> P(x_18) can be inferred via the universal biconditional introduction rule.