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_3. s. s_4 -> ~u_3. p_3 -> ~s.
~s_4 can be inferred via the modus tollens rule. ~p_3 can be inferred via the modus tollens rule. u_3 and s can be inferred via the conjunction rule. s and u_3 can be inferred via the conjunction rule.