diff --git a/polytope/datacube/tensor_index_tree.py b/polytope/datacube/tensor_index_tree.py
index 5cb813b9..604aa744 100644
--- a/polytope/datacube/tensor_index_tree.py
+++ b/polytope/datacube/tensor_index_tree.py
@@ -105,6 +105,7 @@ def add_child(self, node):
     def add_value(self, value):
         new_values = list(self.values)
         new_values.append(value)
+        new_values.sort()
         self.values = tuple(new_values)
 
     def create_child(self, axis, value, next_nodes):