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_2 -> r_11. r_4 -> r_11. p_2 or ~r_11. r_4 or u_2.
r_11 -> p_2 can be inferred via the rewriting rule. r_11 can be inferred via the disjunction elimination rule.