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 01c5a98..832f553 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	
@@ -25,8 +25,10 @@ This is similar to local variables in a procedure of an imperative program
 
 The set of CCS processes is defined by the following grammar:
 $$P::=\sum_{i \in I} \alpha _{i}.P_{i} \space |\space A(a_{1}\dots a
-_{n})\space|\space P|Q \space | P$$
-
+_{n})\space|\space P|Q \space | \space P\setminus a$$
+Dove:
+- **$\alpha _{i}.P_{i}$:** the process $P_{i}$ can perform the action $a$ and continue as the process $P_{i}$
+- $A {\triangle \atop =} P$
 ![](images/Pasted%20image%2020250414103800.png)
 
 ![](images/Pasted%20image%2020250414104010.png)