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, if y_2 were a police officer, then y_2 is a nurse. For all y_2, if y_2 were fast, then y_2 is a police officer. For all y_2, if y_2 were a nurse, then y_2 is fast. For all y_2, y_2 is a police officer if and only if y_2 is fast.
For all y_2, if y_2 were a police officer, then y_2 is fast. For all y_2, if y_2 were fast, then y_2 is a nurse. For all y_2, if y_2 were a nurse, then y_2 is a police officer. For all y_2, if y_2 were a police officer, then y_2 is fast. For all y_2, if y_2 were fast, then y_2 is a police officer.