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_12 or ~q_3. ~p_12. s_2 <-> q_3. u -> s_2.
~q_3 can be inferred via the disjunctive syllogism rule. q_3 -> p_12 can be inferred via the rewriting rule. s_2 -> q_3 can be inferred via the biconditional elimination rule. q_3 -> s_2 can be inferred via the biconditional elimination rule.