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_2 -> q. u <-> p_2. ~u. q_1 -> q.
u -> p_2 can be inferred via the biconditional elimination rule. p_2 -> u can be inferred via the biconditional elimination rule. ~p_2 can be inferred via the biconditional elimination rule.