Consider the following premises. s -> ~p_14. p_14 and u. p. Can we infer s from them? If possible, name the inference rules being used at each step.
 From p_14 and u we can infer p_14 via simplification. Finally, from s -> ~p_14, p_14 we can infer ~s via modus tollens, which contradicts s. Therefore, the answer is no.