diff --git a/.obsidian/workspace.json b/.obsidian/workspace.json
index f5395f5..e1d54a9 100644
--- a/.obsidian/workspace.json
+++ b/.obsidian/workspace.json
@@ -231,9 +231,9 @@
   },
   "active": "0d64f519fd7f9420",
   "lastOpenFiles": [
-    "Concurrent Systems/notes/7- MUTEX-free concurrency.md",
-    "Concurrent Systems/notes/8 - Enhancing Liveness Properties.md",
     "Concurrent Systems/slides/class 8.pdf",
+    "Concurrent Systems/notes/8 - Enhancing Liveness Properties.md",
+    "Concurrent Systems/notes/7- MUTEX-free concurrency.md",
     "Concurrent Systems/notes/images/Pasted image 20250324091452.png",
     "Concurrent Systems/slides/class 7.pdf",
     "Concurrent Systems/notes/6 - Atomicity.md",
diff --git a/Concurrent Systems/notes/8 - Enhancing Liveness Properties.md b/Concurrent Systems/notes/8 - Enhancing Liveness Properties.md
index aa34482..4212bc1 100644
--- a/Concurrent Systems/notes/8 - Enhancing Liveness Properties.md	
+++ b/Concurrent Systems/notes/8 - Enhancing Liveness Properties.md	
@@ -1,2 +1,9 @@
 Can we take the most basic protocol that satisfies the most basic liveness property (obstruction freedom) and "upgrade" it to bounded wait freedom?
 
+**Contention manager:** is an object that allows progress of processes by providing contention-free periods for completing their invocations. It provides 2 operations:
+- `need_help(i)`: invoked by $p_i$ when it discovers that there is contention
+- `stop_help(i)`: invoked by $p_{i}$ when it terminates its current invocation
+
+**Enriched implementation:** when a process realizes that there is contention, it invokes need_help; when it completes its current operation, it invokes stop_help.
+
+Why is it different from lock/unlock? Because this allows failures, and they can also happen in the contention-free period.
\ No newline at end of file