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_15: ~P_15(x_15). exists x_15: U(x_15) -> T(x_15). forall x_15: P_15(x_15) -> T(x_15). forall x_15: T(x_15) -> P_15(x_15). forall x_15: U(x_15) or W(x_15). forall x_15: T(x_15) -> U(x_15).
forall x_15: ~T(x_15) can be inferred via the universal modus tollens rule. forall x_15: P_15(x_15) -> U(x_15) can be inferred via the universal transitivity rule. exists x_15: U(x_15) -> P_15(x_15) can be inferred via the existential transitivity rule. forall x_15: P_15(x_15) <-> T(x_15) can be inferred via the universal biconditional introduction rule. forall x_15: T(x_15) <-> P_15(x_15) can be inferred via the universal biconditional introduction rule. exists x_15: U(x_15) <-> T(x_15) can be inferred via the existential biconditional introduction rule. exists x_15: T(x_15) <-> U(x_15) can be inferred via the existential biconditional introduction rule.