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: q_2 -> w_4. p. w_4 -> u. p_18 or q_2. p_18 -> w_4. p_24 <-> u.
q_2 -> u can be inferred via the transitivity rule. p_18 -> u can be inferred via the transitivity rule. w_4 can be inferred via the disjunction elimination rule. p_24 -> u can be inferred via the biconditional elimination rule. u -> p_24 can be inferred via the biconditional elimination rule.