diff --git a/Concurrent Systems/notes/3b - Aravind's algorithm and improvements.md b/Concurrent Systems/notes/3b - Aravind's algorithm and improvements.md
index 302f1d7..c09f8cf 100644
--- a/Concurrent Systems/notes/3b - Aravind's algorithm and improvements.md	
+++ b/Concurrent Systems/notes/3b - Aravind's algorithm and improvements.md	
@@ -80,3 +80,14 @@ unlock(i) :=
 
 Since the LOCK is like before, the revised protocol satisfies MUTEX. Furthermore, you can prove that it satisfies bounded bypass with bound n-1 -> EXERCISE!
 
+Let's remember ourselves how is the locking function defined:
+```
+lock(i) :=
+	FLAG[i] <- up
+	repeat
+		STAGE[i] <- 0
+		wait (foreach j != i, FLAG[j] = down OR DATE[i] < DATE[j])
+		STAGE[i] <- 1
+	until foreach j != i, STAGE[j] = 0
+```
+