diff --git a/models/Alloy/InventoryManagement.als b/models/Alloy/InventoryManagement.als
index 19fafcf..c450e08 100644
--- a/models/Alloy/InventoryManagement.als
+++ b/models/Alloy/InventoryManagement.als
@@ -1,20 +1,20 @@
 sig ItemId, Name{}
 sig Inventory {
-    itemDB: ItemId lone -> lone Item
+	itemDB: ItemId lone -> lone Item
 }
 sig Item {
-    name : Name,
-    count: Int  
+	name : Name,
+	count: Int
 }
 
 pred init[its: Inventory] {
-    no its.itemDB
+	no its.itemDB
 }
 
 pred itemRegistration[its, its': Inventory, itemId: ItemId, quantity: Int, n: Name] {
 	some it: Item |	{
 		no itemId2: ItemId | its.itemDB[itemId2] = it
-    	its'.itemDB = its.itemDB + itemId -> it
+		its'.itemDB = its.itemDB + itemId -> it
 		it.name = n
 		it.count = quantity
 	}
@@ -30,7 +30,7 @@
 }
 
 pred execute[] {
-    some disj its, its', its'': Inventory, itemId: ItemId, n: Name | {
+	some disj its, its', its'': Inventory, itemId: ItemId, n: Name | {
 		init[its]
 		itemRegistration[its, its', itemId, 100, n]
 		receivingOrShipping[its', its'', itemId, -50]
diff --git a/models/Alloy/InventoryManagementCheckMinus.als b/models/Alloy/InventoryManagementCheckMinus.als
index 1ea8ef3..daced9a 100644
--- a/models/Alloy/InventoryManagementCheckMinus.als
+++ b/models/Alloy/InventoryManagementCheckMinus.als
@@ -1,21 +1,21 @@
 sig ItemId, Name{}
 sig Inventory {
-    itemDB: ItemId lone -> lone Item
+	itemDB: ItemId lone -> lone Item
 }
 sig Item {
-    name : Name,
-    count: Int  
+	name : Name,
+	count: Int
 }
 
 pred init[its: Inventory] {
-    no its.itemDB
+	no its.itemDB
 }
 
 pred itemRegistration[its, its': Inventory, itemId: ItemId, quantity: Int, n: Name] {
 	some it: Item |	{
 		no itemId2: ItemId | its.itemDB[itemId2] = it
-    	its'.itemDB = its.itemDB + itemId -> it
-    	it.name = n
+		its'.itemDB = its.itemDB + itemId -> it
+		it.name = n
 		it.count = quantity
 	}
 }
diff --git a/models/Alloy/InventoryManagementShippingReceiving.als b/models/Alloy/InventoryManagementShippingReceiving.als
index 619d551..3c9f46f 100644
--- a/models/Alloy/InventoryManagementShippingReceiving.als
+++ b/models/Alloy/InventoryManagementShippingReceiving.als
@@ -1,22 +1,22 @@
 sig ItemId, Name{}
 sig Inventory {
-    itemDB: ItemId lone -> lone Item
+	itemDB: ItemId lone -> lone Item
 }
 sig Item {
-    name : Name,
-    count: Int  
+	name : Name,
+	count: Int
 }
 
 pred init[its: Inventory] {
-    no its.itemDB
+	no its.itemDB
 }
 
 pred itemRegistration[its, its': Inventory, itemId: ItemId, quantity: Int, n: Name] {
 	some it: Item |	{
 		no itemId2: ItemId | its.itemDB[itemId2] = it
-    	its'.itemDB = its.itemDB + itemId -> it
-    	it.name = n
-	    it.count = quantity
+		its'.itemDB = its.itemDB + itemId -> it
+		it.name = n
+		it.count = quantity
 	}
 }
 
@@ -39,7 +39,7 @@
 }
 
 pred execute[] {
-    some disj its, its', its'', its''': Inventory, itemId: ItemId, n: Name | {
+	some disj its, its', its'', its''': Inventory, itemId: ItemId, n: Name | {
 		init[its]
 		itemRegistration[its, its', itemId, 100, n]
 		shipping[its', its'', itemId, 50]