2. London emergency control center wants to verify the correctness of its service dispatch protocol. A software engineer specified the protocol in her favorite model checking engine. The officials at the control center reviewed the specification and certified that the specification correctly represents the dynamic behavior of the protocol. The engineer was then given a simple correctness property: whenever the police is dispatched in an emergency, the ambulence is also dispatched in one step (of the protocol) and similarly, whenever the ambulence service is dispatched in an emergency, the police is also dispatched in one step. Accordingly, she wrote the CTL property. She found out that the specified protocol does not satisfy the property. State (and explain) at least two possible reasons why the correctness property is not satisfied by the specification of the protocol. (4)