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_4: R(x_4) -> Q_4(x_4). forall x_4: P_3(x_4) -> R(x_4). exists x_4: Q_4(x_4) -> P_3(x_4). forall x_4: ~P_3(x_4).
exists x_4: ~Q_4(x_4) can be inferred via the existential modus tollens rule. forall x_4: P_3(x_4) -> Q_4(x_4) can be inferred via the universal transitivity rule. exists x_4: Q_4(x_4) -> R(x_4) can be inferred via the existential transitivity rule. exists x_4: R(x_4) -> P_3(x_4) can be inferred via the existential transitivity rule.