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_4. u_4. w_4.
~w can be inferred via the modus tollens rule. u_4 and w_4 can be inferred via the conjunction rule. w_4 and u_4 can be inferred via the conjunction rule.