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: u -> r_2. ~r_2. p_11 -> u. forall x_9: P_9(x_9).
~u can be inferred via the modus tollens rule. p_11 -> r_2 can be inferred via the transitivity rule.