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: s or ~q_9. ~u. s -> u. u -> q_9.
~s can be inferred via the modus tollens rule. s -> q_9 can be inferred via the transitivity rule. q_9 -> s can be inferred via the rewriting rule.