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 -> p_16. u_2 or ~q. p_16 -> u_2. ~p_16.
~u_2 can be inferred via the modus tollens rule. q -> u_2 can be inferred via the rewriting rule. u_2 <-> p_16 can be inferred via the biconditional introduction rule. p_16 <-> u_2 can be inferred via the biconditional introduction rule.