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: exists y_3: T(y_3) -> U(y_3). forall y_3: S_4(y_3) -> R_4(y_3). forall y_3: R_4(y_3) -> T(y_3). forall y_3: ~U(y_3).
exists y_3: ~T(y_3) can be inferred via the existential modus tollens rule. forall y_3: S_4(y_3) -> T(y_3) can be inferred via the universal transitivity rule. exists y_3: R_4(y_3) -> U(y_3) can be inferred via the existential transitivity rule.