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: u -> p_1. p_1 -> s. s -> u. p -> s.
u -> s can be inferred via the transitivity rule. p_1 -> u can be inferred via the transitivity rule. s -> p_1 can be inferred via the transitivity rule. p -> u can be inferred via the transitivity rule.