Consider the following premises. For all x_10, x_10 will sleep or x_10 will take a plane. For all x_10, if x_10 takes a plane, then x_10 is a janitor. There is at least one x_10 for which x_10 will not sleep. For all x_10, if x_10 were a janitor, then x_10 is a taxi driver. Can we infer the following from them? If we can, name the inference rule being used: For all x_10, x_10 is not a taxi driver.
 From the fact that for all x_10, if x_10 takes a plane, then x_10 is a janitor, and that for all x_10, if x_10 were a janitor, then x_10 is a taxi driver we can infer that for all x_10, if x_10 takes a plane, then x_10 is a taxi driver via universal transitivity. From the fact that for all x_10, x_10 will sleep or x_10 will take a plane, and that there is at least one x_10 for which x_10 will not sleep we can infer that there is at least one x_10 for which x_10 will take a plane via existential disjunctive syllogism. Finally, from the fact that for all x_10, if x_10 takes a plane, then x_10 is a taxi driver, and that there is at least one x_10 for which x_10 will take a plane we can infer that there is at least one x_10 for which x_10 is a taxi driver via existential modus ponens, which contradicts that For all x_10, x_10 is not a taxi driver. Therefore, the answer is no.