Now, of course, here we cannot go through in detail, all the different kinds of congruence, I just would like to point out where is one of the crucial, and it is these two are the crucial ones.
Which essentially allow to extend the scope. you see, if this process is equal to that process, then in this case, you can extend this co-local scope of this name over to the bigger process.
Now, this scope extension is one of the key ingredients to the power of this language; because it is a way by which you can communicate along some channel some kind of information that then it will be stored privately in the process Q.