diff --git a/.obsidian/workspace.json b/.obsidian/workspace.json
index dc03cc2..83d1dc2 100644
--- a/.obsidian/workspace.json
+++ b/.obsidian/workspace.json
@@ -242,6 +242,7 @@
   "lastOpenFiles": [
     "Concurrent Systems/slides/class 12.pdf",
     "Concurrent Systems/notes/12 - CCS (che non so cosa voglia dire).md",
+    "Pasted image 20250414173011.png",
     "Pasted image 20250414164549.png",
     "Concurrent Systems/notes/images/Pasted image 20250414082824.png",
     "Concurrent Systems/notes/11 - LTSs and Bisimulation.md",
@@ -253,7 +254,6 @@
     "Concurrent Systems/notes/images/Pasted image 20250414104010.png",
     "Concurrent Systems/notes/images/Pasted image 20250414103800.png",
     "Concurrent Systems/notes/images/Pasted image 20250414102733.png",
-    "Concurrent Systems/notes/images/Pasted image 20250414093017.png",
     "HCIW/notes/3 - Beacons.md",
     "HCIW/slides/Zooming interfaces.pdf",
     "HCIW/slides/Gestural interaction.pdf",
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 8809af1..072ccb2 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	
@@ -153,3 +153,20 @@ 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.
 
+
+### Restriction
+What if we restrict on b?
+
+![](../../Pasted%20image%2020250414173011.png)
+
+$$\frac{a.A' \xrightarrow{a} A' \quad A \triangleq a.A'}{A \xrightarrow{a} A'}
+\quad
+\frac{A \xrightarrow{a} A'}{A \mid B \xrightarrow{a} A' \mid B}
+\quad
+\frac{A \mid B \xrightarrow{a} A' \mid B \quad a \notin \{b, \bar{b}\}}{(A \mid B) \setminus b \xrightarrow{a} (A' \mid B) \setminus b}$$
+$$
+
+
+
+
+$$
\ No newline at end of file
diff --git a/Pasted image 20250414173011.png b/Pasted image 20250414173011.png
new file mode 100644
index 0000000..77d96e4
Binary files /dev/null and b/Pasted image 20250414173011.png differ