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_6: P_2(x_6) -> Q_2(x_6). exists x_6: Q_2(x_6) -> P_6(x_6). forall x_6: P_6(x_6) -> Q_6(x_6). forall x_6: ~Q_6(x_6).
forall x_6: ~P_6(x_6) can be inferred via the universal modus tollens rule. exists x_6: Q_2(x_6) -> Q_6(x_6) can be inferred via the existential transitivity rule. exists x_6: P_2(x_6) -> P_6(x_6) can be inferred via the existential transitivity rule.