diff --git a/.obsidian/workspace.json b/.obsidian/workspace.json
index 70922d9..5cb2bfd 100644
--- a/.obsidian/workspace.json
+++ b/.obsidian/workspace.json
@@ -11,8 +11,12 @@
             "id": "00ae67f71d1252f8",
             "type": "leaf",
             "state": {
-              "type": "empty",
-              "state": {}
+              "type": "markdown",
+              "state": {
+                "file": "Algo/Séminaire/Exercices seminaire.md",
+                "mode": "source",
+                "source": false
+              }
             }
           }
         ]
@@ -81,6 +85,7 @@
             "state": {
               "type": "backlink",
               "state": {
+                "file": "Algo/Séminaire/Exercices seminaire.md",
                 "collapseAll": false,
                 "extraContext": false,
                 "sortOrder": "alphabetical",
@@ -97,6 +102,7 @@
             "state": {
               "type": "outgoing-link",
               "state": {
+                "file": "Algo/Séminaire/Exercices seminaire.md",
                 "linksCollapsed": false,
                 "unlinkedCollapsed": true
               }
@@ -118,7 +124,9 @@
             "type": "leaf",
             "state": {
               "type": "outline",
-              "state": {}
+              "state": {
+                "file": "Algo/Séminaire/Exercices seminaire.md"
+              }
             }
           }
         ]
diff --git a/Algo/Séminaire/Chapter 3 - Case analysis.md b/Algo/Séminaire/Chapter 3 - Case analysis.md
index b2f3ef1..a26b836 100644
--- a/Algo/Séminaire/Chapter 3 - Case analysis.md	
+++ b/Algo/Séminaire/Chapter 3 - Case analysis.md	
@@ -133,6 +133,8 @@ val f : int -> int = <fun>
 # let succ x = x +1;;
 val succ: int -> int = <fun>
 
+(* these two functions are equivalent *)
+
 # let succ = function x -> x + 1;;
 val succ: int -> int = <fun>
 ```
@@ -151,7 +153,7 @@ val avg : int -> int -> int = <fun>
 
 **For the match function**
 ```Ocaml
-# let f x = watch x with 
+# let f x = match x with 
 	| 0 -> 18
 	| 1 -> 24
 	| _ -> x*x ;;
diff --git a/Algo/Séminaire/Exercices seminaire.md b/Algo/Séminaire/Exercices seminaire.md
index cfbc7b5..0949473 100644
--- a/Algo/Séminaire/Exercices seminaire.md	
+++ b/Algo/Séminaire/Exercices seminaire.md	
@@ -1,4 +1,5 @@
-## Exercise 2.2 (Power)
+
+|## Exercise 2.2 (Power)
 
 ```Ocaml
 (*First version ; 6 multiplications*)
@@ -213,5 +214,23 @@ let price w (p1, p2, p3, p4) =
 val price = int -> 'a * 'a * 'a * 'a -> 'a = <fun>
 ```
 
+## Exercise 3.9
+```Ocaml
+let apm = function 
+	| (0, 0) -> 2
+	| (0, y) -> 1
+	| (x, 0) -> 1
+	| (x, y) -> 0
+	| _ -> invalid_arg "Error";;
 
+let strange = function
+	| (0, n) -> 0
+	| (m, 0) -> 2*m
+	| (m, n) -> m*n ;;
+
+let or3 = function
+	| (a, false, false) -> "premier a"
+	| (false, b, false) -> "b"
+	| (false, false, c) -> "c" ;;
+```