What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_12, x_12 will sleep. There is at least one x_12 for which if x_12 sleeps, then x_12 is writing a letter. For all x_12, if x_12 writes a letter, then x_12 is listening to a song. For all x_12, x_12 will take a plane.
There is at least one x_12 for which x_12 will write a letter. There is at least one x_12 for which if x_12 sleeps, then x_12 is listening to a song. For all x_12, x_12 will sleep and x_12 will take a plane. For all x_12, x_12 will take a plane and x_12 will sleep.