What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all y_1, if y_1 plays a game, then y_1 is listening to a song. For all y_1, if y_1 listens to a song, then y_1 is playing a game.
For all y_1, y_1 will play a game if and only if y_1 will listen to a song. For all y_1, y_1 will listen to a song if and only if y_1 will play a game.