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_13 or r. ~s_2. s_2 or q_4. ~p_13.
r can be inferred via the disjunctive syllogism rule. q_4 can be inferred via the disjunctive syllogism rule. ~s_2 and ~p_13 can be inferred via the conjunction rule. ~p_13 and ~s_2 can be inferred via the conjunction rule.