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Concurrent Systems/notes/12 - bastaaaaaaaa.md

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-- Up to now, we have considered non-deterministic processes
-- Two main features are missing for modeling a concurrent system:
-	- Simultaneous execution of processes
-	- Inter-process interaction
-
-- Solutions adopted:
-	- Parallel composition, with interleaving semantics
-	- Producer/consumer paradigm
-
-Given a set of names N (that denote events)
-- a (∈ N) denotes consumption of event a
-- $\bar{a}$ (for a ∈ N) denotes production of event a
-- a and $\bar{a}$ are complementary actions: they let two parallel processes synchronize on the event a
-
-When two processes synchronize, an external observer has no way of understanding what is happening in the system
-- synchronization is not observable from the outside; it produces a special ‘silent’ action, that we denote with τ
-
-The set of actions we shall consider is: ![150](images/Pasted%20image%2020250414102733.png)
-
-It is also useful to force some processes of the system to synchronize between them (without the possibility of showing to the outside some actions)
-
-The restriction operator P\a restricts the scope of name a to process P (a is visible only from within P)
-
-This is similar to local variables in a procedure of an imperative program
-
-![](images/Pasted%20image%2020250414103800.png)
-
-![](images/Pasted%20image%2020250414104010.png)
-
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