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 f0384c5..d61dbf6 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	
@@ -138,4 +138,8 @@ $$\frac{B' \xrightarrow{\bar{c}} B}{A \mid B' \xrightarrow{\bar{c}} A \mid B}$$
 ✅ **Third transition:**
 $$A \mid B' \xrightarrow{\bar{c}} A \mid B$$
 ##### Synchronization
-I
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+In the image above, we can observe a τ-transition due to synchronization between two complementary actions, in fact:
+- A' produces b and becomes A
+- B consumes b and becomes B'
+
+Since $$
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