Consider the following premises. For all x_14, x_14 is a police officer. For all x_14, if x_14 were a soldier, then x_14 is drinking water. There is at least one x_14 for which x_14 is a police officer if and only if x_14 will drink water. For all x_14, if x_14 were a police officer, then x_14 is drinking water. Can we infer the following from them? If we can, name the inference rule being used: For all x_14, x_14 will not drink water.
 From the fact that there is at least one x_14 for which x_14 is a police officer if and only if x_14 will drink water we can infer that there is at least one x_14 for which if x_14 drinks water, then x_14 is a police officer via existential biconditional elimination. From the fact that for all x_14, if x_14 were a police officer, then x_14 is drinking water, and that there is at least one x_14 for which if x_14 drinks water, then x_14 is a police officer we can infer that there is at least one x_14 for which x_14 is a police officer if and only if x_14 will drink water via existential biconditional introduction. From the fact that for all x_14, x_14 is a police officer we can infer that for all x_14, x_14 is a police officer or x_14 is a soldier via universal addition. From the fact that there is at least one x_14 for which x_14 is a police officer if and only if x_14 will drink water we can infer that there is at least one x_14 for which if x_14 were a police officer, then x_14 is drinking water via existential biconditional elimination. Finally, from the fact that there is at least one x_14 for which if x_14 were a police officer, then x_14 is drinking water, that for all x_14, if x_14 were a soldier, then x_14 is drinking water, and that for all x_14, x_14 is a police officer or x_14 is a soldier we can infer that there is at least one x_14 for which x_14 will drink water via existential disjunction elimination, which contradicts that For all x_14, x_14 will not drink water. Therefore, the answer is no.