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: q_6 -> r. r -> u. t -> q_6. u -> t.
q_6 -> u can be inferred via the transitivity rule. r -> t can be inferred via the transitivity rule. t -> r can be inferred via the transitivity rule. u -> q_6 can be inferred via the transitivity rule.