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: r or ~u. s -> u. r -> p_11. p_11 -> s.
r -> s can be inferred via the transitivity rule. p_11 -> u can be inferred via the transitivity rule. u -> r can be inferred via the rewriting rule.