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: ~w -> w_3. w -> ~u_1. u. u_1.
~w can be inferred via the modus tollens rule. u and u_1 can be inferred via the conjunction rule. u_1 and u can be inferred via the conjunction rule.