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 -> p_6. t -> u_2. ~u_2. p_6 -> t.
~t can be inferred via the modus tollens rule. s -> t can be inferred via the transitivity rule. p_6 -> u_2 can be inferred via the transitivity rule.