Consider the following premises. If William were a politician, then Elisabeth is playing tennis. Elisabeth is not a musician. For all x_10, if x_10 plays tennis, then x_10 is a musician. Can we infer the following from them? William is a politician.
 From the fact that for all x_10, if x_10 plays tennis, then x_10 is a musician we can infer that if Elisabeth plays tennis, then Elisabeth is a musician. From the fact that if William were a politician, then Elisabeth is playing tennis, and that if Elisabeth plays tennis, then Elisabeth is a musician we can infer that if William were a politician, then Elisabeth is a musician. Finally, from the fact that if William were a politician, then Elisabeth is a musician, and that Elisabeth is not a musician we can infer that William is not a politician, which contradicts that William is a politician. Therefore, the answer is no.