What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_9, if x_9 were a police officer, then x_9 is poor. There is at least one x_9 for which if x_9 climbs a mountain, then x_9 is poor. For all x_9, x_9 is a cashier. For all x_9, x_9 is a cashier if and only if x_9 is a police officer.
For all x_9, if x_9 were a cashier, then x_9 is a police officer. For all x_9, if x_9 were a police officer, then x_9 is a cashier.