diff --git a/models/Alloy/InventoryManagement.als b/models/Alloy/InventoryManagement.als
index dc9271e..19fafcf 100644
--- a/models/Alloy/InventoryManagement.als
+++ b/models/Alloy/InventoryManagement.als
@@ -11,34 +11,30 @@
     no its.itemDB
 }
 
-pred ItemRegistraction[its, its': Inventory, itemId: ItemId, quantity: Int, n: Name ] {	// 商品登録
-	some it: Item |	
-		{
-			no itemId2: ItemId | its.itemDB[itemId2] = it
-    			its'.itemDB = its.itemDB + itemId -> it
-	    		it.name = n
-	 	   	it.count = quantity
-		}
+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
+	}
 }
 
-pred ReceivingOrShipping[its, its': Inventory, itemId: ItemId, quantity: Int ] {  // 出荷と入荷
-	some it': Item |
-		{
-			no itemId2: ItemId | its.itemDB[itemId2] = it'
-			its'.itemDB = its.itemDB ++ itemId -> it'
-			it'.name = its.itemDB[itemId].name
-			plus[its.itemDB[itemId].count, quantity] >= 0 implies it'.count = plus[its.itemDB[itemId].count, quantity]
-				else it'.count = its.itemDB [itemId].count
-		}
+pred receivingOrShipping[its, its': Inventory, itemId: ItemId, quantity: Int] {
+	some it': Item | {
+		no itemId2: ItemId | its.itemDB[itemId2] = it'
+		its'.itemDB = its.itemDB ++ itemId -> it'
+		it'.name = its.itemDB[itemId].name
+		it'.count = plus[its.itemDB[itemId].count, quantity]
+	}
 }
 
 pred execute[] {
-    some disj its, its', its'': Inventory, itemId: ItemId, n: Name |
-		{
-			init[its]
-			ItemRegistraction[its, its', itemId, 100, n]
-			ReceivingOrShipping[its', its'', itemId, -50]
-		}
+    some disj its, its', its'': Inventory, itemId: ItemId, n: Name | {
+		init[its]
+		itemRegistration[its, its', itemId, 100, n]
+		receivingOrShipping[its', its'', itemId, -50]
+	}
 }
 
-run execute for 2 but 3 Inventory, 8 Int
\ No newline at end of file
+run execute for 2 but 3 Inventory, 8 Int