What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all y_2, y_2 will listen to a song if and only if y_2 will write a letter. For all y_2, if y_2 writes a letter, then y_2 is listening to a song. There is at least one y_2 for which if y_2 listens to a song, then y_2 is writing a letter.
There is at least one y_2 for which y_2 will listen to a song if and only if y_2 will write a letter. There is at least one y_2 for which y_2 will write a letter if and only if y_2 will listen to a song. For all y_2, if y_2 listens to a song, then y_2 is writing a letter. For all y_2, if y_2 writes a letter, then y_2 is listening to a song.