Grading Excerise 8 task 2c)

Question

Why is node 4 necessary. If we delete node 4 and make a edge from node 3 to node 7 with both transitions combined we would have the same behaviour. So technically 4 is a unnecessary node

Answer 1

Hi,

We would not have the same behaviour since the connection is not closed in state 3 if we send a CKE message but it is closed in state 4 if we send the very same message.

However, Mealy Machines are defined in such a way that we always send one input in each transition.
This is essentially a problem in how we define our input alphabet.
Of course, we could always define a symbol which sends a CCS and FIN message, but this is not the case in this task.

Cheers,
Sebastian