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+    "Concurrent Systems/notes/3.md",
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diff --git a/Concurrent Systems/notes/3.md b/Concurrent Systems/notes/3.md
index 45fb2dd..70ae8d5 100644
--- a/Concurrent Systems/notes/3.md	
+++ b/Concurrent Systems/notes/3.md	
@@ -105,5 +105,9 @@ unlock() :=
 	return
 ```
 
->[!info} It is bounded bypass with bound n-1
+>[!note] a>It is bounded bypass with bound n-1>
 
+### Safe registers
+Atomic R/W and specialized HW primitives provide some form of atomicity. But is it possible to enforce MUTEX without atomicity?
+
+A **MRMW Safe register** is a register that provides READ and
\ No newline at end of file