What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: For all x_6, if x_6 were a soldier, then x_6 is a police officer. For all x_6, x_6 is a police officer or x_6 will not sleep. For all x_6, if x_6 plays a game, then x_6 is sleeping. There is at least one x_6 for which x_6 will play a game or x_6 is a soldier.
For all x_6, if x_6 sleeps, then x_6 is a police officer can be inferred via the universal rewriting rule.