diff --git a/.obsidian/workspace.json b/.obsidian/workspace.json
index e52fb22..f7a0e79 100644
--- a/.obsidian/workspace.json
+++ b/.obsidian/workspace.json
@@ -34,9 +34,9 @@
               "type": "pdf",
               "state": {
                 "file": "Concurrent Systems/slides/class 5.pdf",
-                "page": 3,
+                "page": 4,
                 "left": -27,
-                "top": 70,
+                "top": 123,
                 "zoom": 0.5754156769596199
               },
               "icon": "lucide-file-text",
diff --git a/Concurrent Systems/notes/5 - Software Transactional Memory.md b/Concurrent Systems/notes/5 - Software Transactional Memory.md
index 01176dd..9eb3feb 100644
--- a/Concurrent Systems/notes/5 - Software Transactional Memory.md	
+++ b/Concurrent Systems/notes/5 - Software Transactional Memory.md	
@@ -46,4 +46,14 @@ We now present an atomic STM system, called *Transactional Locking 2*:
 	- `lc(XX)`: a local copy of the implementation of reg. X
 	- `read_set(T)`: the set of names of all the registers read by T up to that moment
 	- `write_set(T)`: the set of names of all the registers written by T up to that moment
-	- `birthdate(T)`: the value of CLOCK(+1) at the starting of 
\ No newline at end of file
+	- `birthdate(T)`: the value of CLOCK(+1) at the starting of T
+
+**Idea:** commit a transaction if and only if (iff) it could appear as executed at its birthdate time
+**Consistency:**
+- if T reads X, then it must be that `XX.date < birthdate(T)`
+- to commit, all registers accessed by T cannot have been modified after T's birthdate (again, `XX.date < birthdate(T)`)
+
+###### Implementation:
+```
+poi la scrivo giuro
+```