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: p_1 -> q_2. q_6 -> r_6. q_2 -> q_6. r_6 -> p_1.
p_1 -> q_6 can be inferred via the transitivity rule. q_6 -> p_1 can be inferred via the transitivity rule. q_2 -> r_6 can be inferred via the transitivity rule. r_6 -> q_2 can be inferred via the transitivity rule.