Consider the following premises. For all x_11, x_11 will take a plane or x_11 will not write a letter. For all x_11, if x_11 listens to a song, then x_11 is reading a book. For all x_11, if x_11 reads a book, then x_11 is writing a letter. There is at least one x_11 for which if x_11 were an astronaut, then x_11 is listening to a song. Can we infer the following from them? If we can, name the inference rule being used: There is at least one x_11 for which if x_11 were an astronaut, then x_11 is taking a plane.
 From the fact that for all x_11, x_11 will take a plane or x_11 will not write a letter we can infer that for all x_11, if x_11 writes a letter, then x_11 is taking a plane via universal rewriting. From the fact that for all x_11, if x_11 listens to a song, then x_11 is reading a book, and that for all x_11, if x_11 reads a book, then x_11 is writing a letter we can infer that for all x_11, if x_11 listens to a song, then x_11 is writing a letter via universal transitivity. From the fact that there is at least one x_11 for which if x_11 were an astronaut, then x_11 is listening to a song, and that for all x_11, if x_11 listens to a song, then x_11 is writing a letter we can infer that there is at least one x_11 for which if x_11 were an astronaut, then x_11 is writing a letter via existential transitivity. Finally, from the fact that there is at least one x_11 for which if x_11 were an astronaut, then x_11 is writing a letter, and that for all x_11, if x_11 writes a letter, then x_11 is taking a plane we can infer that there is at least one x_11 for which if x_11 were an astronaut, then x_11 is taking a plane via existential transitivity. Therefore, the answer is yes.