Consider the following premises. For all x_13, x_13 is a sailor or x_13 will work. For all x_13, x_13 will write a letter. For all x_13, if x_13 writes a letter, then x_13 is a police officer. For all x_13, if x_13 were a sailor, then x_13 is a taxi driver. For all x_13, if x_13 works, then x_13 is a taxi driver. Can we infer the following from them? If we can, name the inference rule being used: Michael is not a police officer.
 From the fact that for all x_13, if x_13 were a sailor, then x_13 is a taxi driver, that for all x_13, if x_13 works, then x_13 is a taxi driver, and that for all x_13, x_13 is a sailor or x_13 will work we can infer that for all x_13, x_13 is a taxi driver via universal disjunction elimination. From the fact that for all x_13, x_13 will write a letter, and that for all x_13, x_13 is a taxi driver we can infer that for all x_13, x_13 will write a letter and x_13 is a taxi driver via universal conjunction. From the fact that for all x_13, x_13 will write a letter and x_13 is a taxi driver we can infer that for all x_13, x_13 will write a letter via universal simplification. Finally, from the fact that for all x_13, if x_13 writes a letter, then x_13 is a police officer, and that for all x_13, x_13 will write a letter we can infer that for all x_13, x_13 is a police officer via universal modus ponens, which contradicts that Michael is not a police officer. Therefore, the answer is no.