diff --git a/Concurrent Systems/notes/12 - CCS (che non so cosa voglia dire).md b/Concurrent Systems/notes/12 - CCS (che non so cosa voglia dire).md
index d61dbf6..8809af1 100644
--- a/Concurrent Systems/notes/12 - CCS (che non so cosa voglia dire).md	
+++ b/Concurrent Systems/notes/12 - CCS (che non so cosa voglia dire).md	
@@ -142,4 +142,14 @@ In the image above, we can observe a τ-transition due to synchronization betwee
 - A' produces b and becomes A
 - B consumes b and becomes B'
 
-Since $$
\ No newline at end of file
+Since $\bar{b}$ and $b$ are complementary actions, they can **synchronize**, resulting in a **silent action** $\tau$ (synchronization rule):
+$$\frac{A' \xrightarrow{\bar{b}} A \quad B \xrightarrow{b} B'}{A' \mid B \xrightarrow{\tau} A \mid B'}$$
+
+### LTS and parallelism
+In the construction of the LTS we loose the consciousness of the parallel
+- it is indeed possible, by having the new set of actions, to obtain the previous LTS through the syntax we considered last class.
+
+The usefulness of the parallel is two-fold:
+- it is the fundamental operator in concurrency theory
+- it allows for a compact and intuitive writing of processes.
+