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_13 -> r. s -> t. t -> r_13. s or ~r.
s -> r_13 can be inferred via the transitivity rule. t -> r can be inferred via the transitivity rule. r -> s can be inferred via the rewriting rule.