Consider the following premises. For all x_11, x_11 is not a police officer. For all x_11, x_11 is a police officer or x_11 is curious. If Richard were curious, then David is running. Can we infer the following from them? If we can, name the inference rule being used: David is not running.
 From the fact that for all x_11, x_11 is a police officer or x_11 is curious, and that for all x_11, x_11 is not a police officer we can infer that for all x_11, x_11 is curious via universal disjunctive syllogism. From the fact that for all x_11, x_11 is curious we can infer that Richard is curious via universal instantiation. Finally, from the fact that if Richard were curious, then David is running, and that Richard is curious we can infer that David is running via modus ponens, which contradicts that David is not running. Therefore, the answer is no.