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 -> t_4. u_4 -> r. p_1 -> s_1. t_4 -> q. s_1 -> u_4.
r -> q can be inferred via the transitivity rule. u_4 -> t_4 can be inferred via the transitivity rule. p_1 -> u_4 can be inferred via the transitivity rule. s_1 -> r can be inferred via the transitivity rule.